That's what they call compartmentalization that's why your right hand never knows what your left hand is going to do with it and neither does anyone in it Bingo Homeland Security
I was on The Hill digging through a warehouse , probably ETEC, for some directed energy stuff and I look under a tarp.... HOLY CRAP a flippin linear aerospike just sitting there! Amazing. I climbed on top of it and poked around a bit, why not. I wonder where it went when everything was hauled off.
I was fine with developing the aerospike engine but the X-33/Venturestar was about developing far too many technologies in one demonstrator to expect success during the limited period of government financial support. It was too many eggs in one basket, they should've done something like the Delta Clipper with the option of a ring aerospike but designed for a conventional engine. The goal of establishing a crew launch vehicle should've been the main consideration given the complexities of the Shuttle and the obvious need to replace it.
You guys did some good work. I supported X-33 here and there in the 90’s a little. Too bad Lockheed tried to implement too many technology jumps in X-33. Being a shuttle tile engineer, i found it interesting LM was moving toward metallic TPS. Funny though, even LM abandoned the idea and are using ceramic tiles on their Orion capsule. Sierra Nevada is using ceramic tiles as well, and we hear Elon is moving toward ceramic TPS too. It would appear there isn’t anything better than the 60’s technology ceramic insulation for use on entry vehicles.
true,that leads also in using just one aerospike engine instead of multiple engines in different stages,so also less weight for additional engines without also having the problem of dealing with returning stages.
@@Wrongway346 it is the very basis of rocket science: at the ignition the engine must lift all the rocket including all the fuel, so the consomption is higher. If you need to go at 200 km orbit for example, you need a powerfull enough engine, but now you need the fuel to feed it, and now you need a more powerfull engine, and more fuel, etc. The result is massive rockets with a mass/power ratio making posdible to reach the wanted orbit. So, an engine more efficient is extremely interesting, because less fuel means a big down sizing for the same purpose
also single stage spacecraft would mean no complex staging and less travel planning. You just need to actually pilot the ship towards your destination without timing every stage operation
@BRRP Yeah, I think it's easy for people to second guess what's being said. It sounds like the efficiency to mass savings calculation was already done. The engine probably isn't 40% more efficient, but even a marginal increase in efficiency rapidly pays dividends in rocketry.
After graduation (BS, MS engineering), I landed a job that partly fulfilled my dream to be an astronaut. Rocketdyne was then a division of Boeing. I went straight to advanced programs as a member of the XRS-2200 Engine, which is the Aerospike engine we see featured in this video. The X-33 faced a problem. The fuel tanks would not withstand the required fuel pressurization. Benefit to cost issues also started to make NASA lose interest. Yet, as the premier liquid engine propulsion in the World, Rocketdyne delivered. I had already jumped to Atlas and Delta propulsion, then the Space Shuttle Main Engine when I visited the test stand (B1, if I recall well) being set up for test at SSC. Extensive data was collected, and improvements in performance were noticed. These data will someday be helpful for an entity that is serious about the Aerospike. By the way, we need to encourage the newer generations to study science and engineering to keep the edge. God bless.
Unfortunately, with the break-down in society (specifically the highest, by-far, divorce rates in the world) kid's in the US no-longer have the schooling & home discipline, or even desire to pursue the hard sciences as they once did in your generation...Most military personnel in high command now consider this to be a national security concern 😰
Check out the movie "Unacknowledged", might give you all a hint to what's actually going on. Indeed money is important, but only because money = power to rule.
@Justin Rowe that's true. Even Elon musk is having to follow the most proven methods for space travel. Due to cost and profit. Regardless of how much he wants to develop new tech. He's still locked in the economic system.
There is a big Achilles Heel with the aerospike nozzle that is not talked about much in the technical literature...but is fundamental to fluid mechanics... It has to do with the surface to volume ratio of any heat engine or nozzle...a big engine will always be more efficient than a small engine, all else being equal, due to the fact that internal surface area increases only by the square, while volume increases by the cube... The surface area is where viscous losses occur [friction losses in the boundary layer of the flowing fluid at the wall]...while the volume is what determines mass flow, which determines power... If you increase engine [or nozzle] size you decrease the surface to volume ratio which means less fluid comes in contact with the wall [in proportion to the mass flow], and your boundary layer is small compared to the volume and mass of fluid you are moving... With the aerospike design you greatly increase the surface area for any given mass flow, compared to the standard bell [de Laval] nozzle... You can see this by by looking at the two respective geometries...on a bell nozzle the sonic throat surface area is much smaller than on an aerospike 'toroidal' [axisymmetric] design...where the flow has to go around a donut-shaped center body in the middle of the flow...[also you now have two surfaces, an inner and outer, as opposed to just the outer surface of a de Laval sonic throat] The result is that viscous losses will be much greater in the aerospike...thus increasing pressure loss through the nozzle...as more of the fluid has to 'scrub' against the donut surface... Nozzle efficiency is directly a function of pressure loss...so you want to have as little pressure loss as possible...we recall from basic thermo that only pressure energy can be converted directly to work energy in a heat engine...so pressure is the 'coin of the realm' in any heat engine... The 'linear' [2-D nozzle] aerospike concept is similarly bad in that respect, perhaps worse...you can see that you have, in effect, a whole bunch of little 'nozzles' lined up next to each other and directing the flow against the central 'spike'... This is like having a whole bunch of tiny little nozzles, as opposed to one big nozzle...one big nozzle will always be more efficient for a given mass flow than a number of smaller nozzles...again for the fundamental principle of surface to volume and the resultant effect on viscous losses... This is one of the reasons why the F1 engine was so effective...it had one huge nozzle...even though it had relatively low chamber pressure [about 1,000 psi...barely a quarter of what Russian high pressure engines achieve] The difference in surface to volume ratio of an aerospike engine compared to a conventional nozzle would be at least an order of magnitude if not more... That is one of the reasons we have not seen continued interest in the aerospike...it is fighting the laws of physics... Another aspect that is not mentioned is chamber pressure...an engine with higher chamber pressure will be less sensitive to the losses that occur as a result of a flow that is not perfectly expanded at all flight regimes [ie altitudes]... This is due to the fact that higher chamber pressure requires a larger nozzle area ratio...[the ratio of the exit area at the base of the bell to the sonic throat upstream]... The higher your pressure, the longer the bell and the bigger its exit area...which means that the compromise at off-design ambient pressures will be less severe...ie you can select a bell length that can perform well [although not optimum] at varying altitude... We saw this in the design of the hydrogen-fueled Shuttle main engines [RS25] which needed to work from launch to space...the engine achieves a chamber pressure of ~3,000 psi...using a fairly complex two-stage turbopump... With the high pressure the nozzle was able to be sized as a good compromise at all altitudes and ambient pressures...from SL to space... This is one of the reasons that Nasa concluded in the early 1980s that high pressure kerosene-fueled engines need to be developed...something the Soviets had already done in the 1960s with the NK33... See Nasa technical report 19820002372 'Fuel/oxidizer-rich high-pressure preburners [staged-combustion rocket engine]' However this has not happened...high pressure engines are not practical on the simple gas generator cycle which dumps the exhaust used to drive the turbopumps overboard...a staged combustion cycle is required...[as on the RS25 and all the Russian high pressure engines] This, in turn, requires advanced turbopump capability...supposedly the BE4 engine in development now will use a staged cycle [with projected chamber pressure about half that of the Russian engines]...but SpaceX engines use the gas generator cycle and the company does not even make its own turbopumps [which are made by Barber-Nichols]... Another issue with this video is that the single stage to orbit concept is tied in with the aerospike engine...which are really two independent ideas... There are many different schemes and concepts for SSTO and the issue of nozzle performance is not even the major factor here...it is about the mass ratio... We see this in the Tsiolkovsky rocket equation where delta v = specific impulse * gravity * natural log of mass ratio... So we see from this relation that at a given engine ISP it's all about the mass ratio..ie the fundamental problem is still how to get enough fuel and oxidizer on board to get you to orbit in a single stage... Even if you could make the nozzle more efficient by addressing the altitude problem it does not follow that you have solved the mass ratio problem... Another point that is overlooked here is that any bell nozzle could conceivably achieve perfect expansion at any altitude IF the chamber pressure is somehow able to be varied...this gives the same result as changing the nozzle geometry to compensate for altitude... For instance at SL launch we can use a lower chamber pressure to prevent overexpansion and increase pressure as we climb out to prevent underexpansion... Of course this would be quite tricky for the turbopump as turbomachinery is also designed to have an optimum performance at a particular rotation speed and mass flow etc... But the bottom line is that the aerospike is really a non-starter due to the viscous loss issue...and second, aerospike [or more broadly perfect nozzle expansion throughout the flight regime, however it is achieved] is in no way a 'solution' to the SSTO challenge...
Jet Guy - Cool read. Thanks for that. That's always the issue I had with the aerospike is that the expanding gas has too much to do before it actually generates thrust. So much lost energy through all the complexity. Bells for the win! I mean hell the aerospike doesn't even have the greatest isp. Jack of all trades master of none.
Jet Guy, Forty-five years after seeing that first photo of an aerospike on a test stand I've still never seen a proof-of-concept ballistic flight powered by an aerospike. The ground tests are so visually appealing that hard-boiled aerospace companies give the concept third chances. _Thanks for stating the flaw in the concept._ I'll still be on the lookout for that launch but more and more it looks like the flight realm may be confined to imagination.
Jet Guy - SSTO rockets must lift a lot of dead weight all the way to orbit, that multi stage rockets jettison after the fuel is consumed, improving the mass to thrust ratio each time a stage is jettisoned. Your very informative write-up indirectly states this, but for clarity, I state it directly.
Interesting thanks, food for thought, I am guessing there is a way around some of this within so called conventional physics, will be sleeping on this - many thought experiments as prelude to 'provoked' lucid dream states ;-) Thanks again for your effort in describing this in good detail, hope you don't mind questions later on, cheers
Isn't it that you have more pressure at sea level and under expansion is the problem, with less at higher altitudes where overexpansion is the problem? Otherwise seemed very quite correct and obviously correct.
AwesomeBlackDude can't you read? I meant you being a Flat Earther! because you are questioning how it was done that the van Allen belt was discovered. It is called mathematics!
People are pointing that out a lot in the comments and it would have been nice if Droid mentioned that in the video. That's less fuel needed plus you only use one engine means a much lighter vehicle. I don't know if it's enough to offset development costs, but it sounds worth looking into. That being said, these companies employ a lot of very smart people so it probably has been looked into and something about it doesn't look good enough to go after.
You also have to factor in mission flexibility of SSTO on a reusable craft. Faster turnaround and you can potentially land anywhere with a long enough runway.
with NASA funding being less than a fraction of US gdp, I bet that aint the issue... There's too much rich people spending money in useless luxury instead of funding useful science, useless wars and excessive expending, too much corporate lobbying... whatever. given the US government snail pace at funding space, it'll probably be private corporations to keep things going on, and other countries governments.
What makes you think it’s not still being used for current research and development? Just because NASA doesn’t show the public doesn’t mean they’re not still building spacecraft.
LazicStefan Welfare? Really? That's what is sucking the money out of NASA? Couldn't possibly be the fact that our annual military budget is over $500 billion dollars.
Aerospike can still be used for non-SSTO rockets. With SpaceX they can use it on the 1st stage part of the rocket and if the 2nd stage is needed to land then they can use the Aerospike on it as well. Some crazy reusable rocket that lands in different atmospheres as part of a mission to multiple bodies in one trip, Aerospike is the way to go.
your manner of speaking is pleasant and easy to listen to. you do show your face, which i normally find super annoying when other presenters do so, but you dont hog the camera with ego and you only demand our attention long enough to get across the desired relevant info; never stopping to attempt comedy or worthless sideshow spectacle . great work, thank you.
The primary reason for multistage rockets is not to allow for different engine nozzle sizes, it's to shed huge amounts of weight allowing for a far greater payload to orbit. An aero spike is less efficient in a multistage rocket, as it's worse at both sea level and in vacuum. Once above the atmosphere you don't need the same thrust you needed at sea level to get off the ground, you just need very efficient continued thrust to build up your orbital speed. An SSTO rocket is by design an inefficient way of getting to space, and with full booster reusability just a year or two down the road, SSTO can finally be put to rest.
Yes, that is very true. We seem very biased to thinking of one-part vehicles. So we imagine hopping in our rocket and scooting into orbit 'cause that's like our everyday experience. With chemical reactions, mutli-stage is the only practical choice. Nuclear propulsion is a different matter, but then we have other concerns... Also, you might find this link interesting - jim-cantrell.squarespace.com/blog/2016/11/8/failure-is-the-seed-of-growth-for-success-lessons-learned-from-developing-and-testing-aerospike-rocket-engines In particular, Jim states: "The point behind all this is that, while aerospike engines can provide performance advantages. The larger number of parts and components means that they are usually heavier than their regular bell-nozzle counterparts (in terms of thrust-to-weight) and, more importantly, require very high component reliability." Consider a linear aerospike engine with 8 combustion chambers along each side -- that's 16 combustion chambers with attendant injectors, valves, controllers, ignitors, perhaps propellant pumps, and piping. Compare to a single chamber bell-nozzle design. Yes, the engine is more efficient at turning chemical energy into motion; however, the overall vehicle performance is worse.
You might want to look at the Linear aerospike stats. It was more efficient at sea level than a lot of standard boosters and as it rose became even more efficient and powerful when in orbit. There are some exceptions to this and they come from long term testing and design tweaking. If the linear aerospike had been in operation for all the same years I promise you it would have been improved to incredible levels by now.
Is this just a hobby to you, or some way to eventually commercialize yourself that I haven't figured out yet? Will we eventually see Justin Y comments with "this comment was brought to you by Brilliant dot org. Sign up today with promo code Justin to....."
It disgusts me that companies are too concerned with having maximum profits to make progress. That's all any business today cares about is maximum profit, getting every single penny they can squeeze out of something.
@@NaeroSpace corporations can afford it. They choose not to invest because they are only concerned with making *maximum* profit. If a huge profit can't be made they aren't interested and I find it gross.
yeh i thought that was a stupid argument. Fuel efficiency doesn't mean you use less fuel, it means you use the same amount but get way more delta-V and therefor payload
Yes- weight is much less critical for the lower stages since they only undergo about a third of the acceleration. Fortunately the lower stages are the big, expensive ones and the easiest to recover. A reusable first stage is the low-hanging fruit, so it's nice to see SpaceX succeed at this.
I think the main benefit of fuel efficiency isn't saving cost on fuel, but using that to have a higher payload rather than having to carry that much more weight in fuel, and at the end of the day the payload is what makes you money. If you can save several tons of fuel that is several tons of satellite you can send up.
Yes. Also if you need same mass delivered - less fuel means smaller fuel tanks, smaller rocket and less weight in general (which means it's easier to construct) and so on.
It's all about the mass fraction savings. SSTO isn't possible without improved efficiency. SpaceX is betting that the operational complexity of a fully recoverable TSTO solution will be "good enough" to truly open the skies. If they can hit their aspirational cost numbers, they'll be right... probably igniting an SSTO race to do to SpaceX what SpaceX is doing to ULA .
i was nder the impression stages were additionally used to dispose of empty weight, being able to drop 75% of the fuel tank weight seemed like a good tradeoff to make
That's the major reason for staging, but you'd need a lot more fuel if you use an engine bell not optimized for the atmospheric pressure you're flying in. This is why when they fly Delta IIs with 9 boosters, only six are ignited at launch. The remaining three have engine bells optimized for higher altitudes, and are ignited later in flight. I'd assume that if they used aerospike engines (not that they'd work with solid propellant, but for the sake of the argument), they could get better efficiency out of each engine, and could afford to burn them longer with better average thrust across the entire flight, reducing the total weight and fuel required to get to orbit.
well said @thebigitchy, but they do work with solid propellants, at 9:15 of the video I mention the NASA test of a solid fuel toroidal aerospike, they should work on any chemical fuel engine that currently run on bell nozzles.
Had this video been made just ten years ago then there would have been a lot of head scratching about why nobody had taken the aero spike engine development further. However the latter part of this video introduces the commercial component to rocket launching. If the cost of development of the aero spike engine cannot be recouped against the backdrop of reusable traditional bell housing rocket engines then they will remain a ‘what might have been technology’; making them part of the X33 SSTO program put too many eggs in one basket. The linear aero spike engine does have desirable attributes from an operational and manufacturing view point due to its being essentially modular. Small repetitive combustion chambers are ideal candidates for mass production. The overall engine thrust is scaleable by simply varying the number of chambers. Cutting ignition to individual chambers effectively throttles the entire engine allowing reduction in thrust at max Q and booster landing. In many ways the annular arrangement of multiple engines as envisaged for SpaceX’ BFR booster creates a virtual aero spike.
I think that's an important point - especially if you're recovering your stages, staging counters most of the argument for areospikes. Yes, they are more efficient at a variety of altitudes, but they are less efficient at any one altitude. So, if you're staging *anyway*, there's less need to use an areospike. You can build your stages so that the loss of efficiency is minimal, getting most of the effect of areospikes without switching to an untested technology. Areospikes are brilliant for single-stage-to-orbit designs - but there's lots of reasons not to use those designs in the first place, which areospikes don't counter.
@ Daniel Staal The aerospike is the optimal engine for the first stage where the atmospheric pressure drops fast but for space work vacuum optimized bell engines are better.
Most people do not know, but to prevent the 'Bell' nozzles from melting, the nozzles have thin pipes in them, and the liquid fuel is vaporized as it goes through causing a refrigerant effect before the gas is sent into the nozzle to be burnt for thrust. This is the main reason we do not have thrust vectored engines like on the F22 Raptor, yet, as the mechanics required for vectoring, cooling and safety is very complicated, heavy and very expensive.
The Saturn V had thrust vectoring on the first stages, with regenerative cooling of the upper bell. The four outer engines all had thrust vectoring and that was in the mid-60s
The main reason that we use multiple stages on rockets is weight, not engine performance. An empty fuel tank is just dead weight, so you can as well just drop it. Using multi stage rockets saves a ton of fuel and also reduces the size of these things significantly.
Deus EXmachiA I think the other part of why staging is used is because the engine attached to the empty fuel tank has a significant mass as well. If the engine wastes less fuel on an inefficient nozzle design, that might mean the rocket needs less fuel to go to the same altitude. That probably lowers the size and weight of the fuel tank, reducing the need to drop separate stages.
In old Soviet books on rockets I saw an interesting design where the rocket worked as a syringe. As it burned it got shorter and shorter and the excess tank walls just got burned or gradually dropped. This could be the next evolutionary step because it allows to go from a number of discrete stages to a continuous single stage. It also saves on engine weight. Now add to this a variable shape nozzle and you got yourself an ideal chemical rocket.
+Ivan Bulanov That sounds fantastic in both senses of the word. It sounds like it could be amazing if done right... ...but it also sounds like a fantasy concept that would be impossible to implement. I mean, if someone does find a way to make it work? Great! But I'm unconvinced that it can be done.
Damn the cost! Nasa needs to bring back the Venture Star program, re-vamped, with Space X as a partner. We need a shuttle replacement that works well!!
That should be the title of your video : "Nasa's Big Mistake" Or maybe a Future Video?? I even built a hybrid electric/rocket plane, and called it "Future Star". here is a link: th-cam.com/video/J7f8hf8kgfg/w-d-xo.html
the space shuttle design is retardedly complicated compare to the design of the BFR. Plus NASA does not get the infinite cold war funding it had. The tech space x uses was already available but NASA does not have the capability to exploit it due to its retarded structure. Space x also has few competitor on the same level because of the Business mentality of "if it works, it's good enough". SSTO like in science fiction wont happen until we make powerful and efficient energy sources and extremely efficient engines. Yet most of the planet is still fucking around with combustion engines and wind or inefficient solar energy like solar pannels
I saw the partially assembled X-33 in its abandoned hanger back in 2004. Crazy to see such a high tech machine abandoned and covered in owl shit. Making the fuel tanks in the shape necessary for that lifting body platform is just too complicated, and materials haven't changed much since then. It'd be interesting to see a conventional cylindrical rocket using them though.
Nope, NASA dodged a bullet. First, the contract that NASA had with LockMart was a "prove it' contract, they got a fixed one billion dollar contract, if they exceeded that amount, LockMart had to eat it. They exceeded the billion dollars, LockMart had the nerve to ask NASA for more money and NASA said "Did you read the contract you signed?" By that time, LockMart wasn't going to do so and they stopped all work on the X-33, then a year later tried to hand it off to the USAF and they got laughed at. Why? Because... Second, the X-33 was attempting to use technologies that had never been used for spacecraft, including composite laminate fuel tanks to save weight; and here's when things got ugly; during a tanking test of the X-33, when they were refilling the tanks with liquid nitrogen, one of the two tanks proceeded to split like an overcooked hot dog. This caused LockMart to consider adding metal fuel tanks to replace the composite laminate, which led to the issue that killed it. Adding metal fuel tanks increased the weight of the X-33 to where it could not launch from the pad, it would have been too heavy-and that's when LockMart went to NASA and started begging, with NASA telling them to stick it and the USAF running away as fast as they could. And mind you, the X-33 was a quarter scale prototype, not a full scale one. Don't blame NASA, blame LockMart.
I think multi stage rockets are the better way to go. As he said, bell nozzles are more efficient for specific atmosphere. But the big advantage of multi stage is that it sheds vehicle weight as you climb. Less weight, the better. Why do you want to continue to carry all that mass all the way into orbit if you don't need it? Also, once in orbit, you have to re-enter the atmosphere, and that is when you really want the smallest and lightest vehicle. Smaller re-entry vehicle means less shielding, and less weight means easier to land.
Bro, when you take away all those stages away, how much less fuel do you need? Those stages are literally just engines and fuel tanks, anything without stages is going weigh less, fact. I am not saying aerospikes are the way to go, I am saying your logic is flawed
I did a highschool report on the Venturestar/X-33 program. Got in touch with people at Lockheed Martin in the program and alot of cool goodies including a very detailed wood model. 😎 I was crushed when it was cancelled.😕
I was there at Lockheed Martin. We had just merged with Lockheed, I started at Martin Marietta. We were all excited about VentureStar, and I hoped to be able to test the flight software in my test lab. I was also crushed when it got canceled. The X-33 was the 53% scaled prototype that they actually built. But it had LOTS of problems - too many for one video. I thought it was the coolest thing ever. They would have built it if they still had the courage that they did in the 1950s and 1960s. But we weren't competing against the Russians anymore, and NASA had become a bunch of misers, too cheap to actually build anything. Notice that there still isn't a replacement for the space shuttle, even today. They were planning on using Russian rockets because they were supposedly cheaper - how would that even work now.with Russia invading Ukraine? Then they wanted to strap Boeing Starliner on top of Russian rockets, and look how terribly the Starliner program is going - NASA doesn't want to pay for any mistakes or setbacks. You can say it's about cost, but it's really about NASA not willing to spend money that they used to. Right now, America is willing to sit back and let China and India take over dominion of space. Until we find gold in space or have another space race, American leadership is space is ending.
I think that the problem with aero spike engines in order for them to be successfully profitable is the size of the engines themselves. In all of the canceled projects that were using the engine (and all of the canceled uses of the engine in projects that were otherwise approved), your video shows that the aero spike engine that is being tested is HUGE in comparison to the engineers doing the testing. Bigger doesn't always mean better. Using multiple smaller sized aero spike engines instead of one big engine would probably prove to be more effective and more profitable. It might also prove to be safer if one of engines fails during testing, but the other engines keep working, the failed engine could be isolated and shut off until the test is over so that the engine could be examined afterwards to determine the cause of the failure. This would then help to minimize (if not prevent) disaster level accidents from occurring due to engine failure.
The aerospike was the only thing I liked about the Venturestar/X-33 project. I thought choosing that project was betting on too many high risk technologies at one time and they would've been better off focusing on proven technologies to get back into space which eventually is what we're doing now. My choice would've been the Delta Clipper just to get back into space then work on the technology demonstrators.
I've been fatally sick for 4 days clingy to life after being poisoned and your page helped me stay calm and get through it. I didn't even know I liked space. Thank you man just Thank you. I was so scared
@emma harrington thank you I was suicidal and on drugs. I am no 3 months sober on 5/16/19. With out this his videos to keep my call I never would have made it to get the help I needed to get better.
Also ditching fuel tank weight as they empty kinda encourages multi-stage designs anyway. That reduces the range of altitudes an engine needs to work over.
Steven Clark That's a good point. Until this video, I'd thought it was dropping the empty weight, and making landing/recovery easier, that were the main reasons for multi-stage heavy lifters.
Steven Clark This is true, but dropping pieces of the rocket into the ocean means the rocket has to be rebuilt if used again. If the rocket is one piece and can be landed safely all you have to do is refuel it.
syaondri That sounds like it would work, although it would probably complicate other things. _Sounds_ _Like_ _It_ _Would_ _Work:_ The USAF and USN have used detachable external fuel tanks on their fighters for decades. Even better, there's a certain type that bolts onto the airframe directly, called "conformal fuel tanks" because they're not the more traditional cigar-shaped pod hanging off the underside. My understanding is these CFT's are the best bet for extending a fighter's range, because not only do they let it carry more fuel, but they don't cause a lot of extra drag the way a more standard external tank does. _Would_ _Probably_ _Complicate_ _Other_ _Things:_ The disadvantage of CFT's is they can't be dropped to shed weight and improve the plane's aerodynamics. Once they're on, they're on until the ground crew disconnects them. The reason is, the tanks are wired into the plane's fuel system, rather than keeping the internal fuel tank topped off like external fuel pods do. I'd imagine trying to shear off something that long and close to the fuselage - the CFT's on the F-15 are something like 20 feet long - would make flying really tricky, too, but that's mostly speculation. Either way, it would change the plane's balance and handling very suddenly, and rockets' failure rates are scary enough without adding more things that could suddenly decide to go squirrelly. _Why_ _Consider_ _CFT's_ _At_ _All,_ _Then?_ Because big external tanks impose a _lot_ of extra drag. That means you need a bigger engine to toss the whole contraption into space, which means you need _more_ fuel, which means an *even* *bigger* engine, which means... And so on. Tsiolkovsy's rocket equation isn't complicated, as rocket science goes, but it is absolutely merciless. All that said, I would not be surprised at all to learn that a group like SpaceX is working out the math so they can add extra fuel tanks that A) aren't also the engines themselves, like the STS and multi-stage rockets use, B) conform to the main rocket body such that they don't add horrible amounts of extra drag, and C) can be safely shed once they're empty. It's an engineering challenge, and rocket scientists are pretty good at that kind of thing. Here's hoping!
Internally-stored, ejectable fuel tanks? I had not thought of that, that's clever! Ditching the empties would change the center of gravity, but then, so does dropping the large external tanks, booster rockets, and empty stages currently in use, so that would happen either way. Yeah, the more I think of it, the more I like that idea. And space guns! An engineer by the name of Gerald Bull was working on the idea of shooting payloads into orbit in the 1970's/80's, until the Israelis decided his practice of building cruise missiles and gigantic cannons for the Iraqi Hussein regime probably wasn't going to end well, and had him whacked. (...Well, we don't _know_ it was the Israelis: they certainly had a motive to bump off a weapons designer in Saddam's employ, but so did a lot of other people, like the Syrians, Iranians, South Africans, CIA, MI6, and a bunch of others. I guess building weapons is a dangerous job, for some reason.) At the time, the big problem with Dr. Bull's design was that the shock of firing would be immediately lethal for any astronauts. A railgun's ability to spread the acceleration out beyond the immediate impulse seems like it could solve that, if you made the launch facility long enough. And, of course, an orbital elevator would solve all these problems to the point of triviality. We just need to find or make something strong enough to reach that far under tension.
I very much wish to compliment you on the fine work that you do. Coming from a family whose dad was one of the early engineers in the early days of the space and missile programs for the United States, I very seldom see any presentations that are more than conjecture with little fact based. You are an outstanding representative of what a presentation should be, and have done your research quite well with the ability to throw out the gossip and rumor mail base facts and purely discuss and present the real scientific based evidence on every program you present
@2:35 Whilst it's true that we have evolved to live at (more or less) one standard atmosphere, and we can't survive for too long if that poressure is reduced to about half that, that is not the reason we don't feel atmospheric pressure. If we truly did have a net pressure of 14.5 pounds bearing down on every square inch of our body, then trust me, we would really, really feel that. That actual reason why we don't feel atmospheric pressure, is that our bodies are permeable. That is there is 14.5 PSI pushing outwards which makes the net pressure on any point of our body zero. That's also how commercials divers have descended to 500 metres where the pressure can reach 700 PSI. That's not so say that there aren't physiological issues due to the differences in partial pressure of gases. Those who are diving to considerable depths have to use special mixes of gases to avoid the toxic effects of normal gas mixes at high pressure, but they don't actually "feel" the pressure due to that internal and external equalisation.
Yep. That's the real reason. It allows us to use better optimized engines, but that's not the real reason. The rocket equation necessitates enormous mass ratios to get high changes in velocity, especially for orbit. There are limits, however, to how light a fuel tank can be. To circumvent this, we can put a separate fuel tank on top, with its own engines. This lets us cheat and get a higher effective mass ratio.
Well, the initial stage is fully capable to lift the entire mass of the rocket, but at a plain acceleration ratio, to increase the TWR (thrust/weight ratio) the rocket needs to loose mass while accelerating. So, both are the reasons for staging. Try it with Kerbal Space Program game hehehhe
I think this is perhaps the best description of how atmospheric pressure affects rocket engines. Thank you for helping me to understand this. When you mentioned that it was "quite simple" I thought "I'm sure not going to understand it now", however you explained it very well so that even I could understand it.
We stage mainly because of the mass ratio. Staging reduces the required mass ratio to achieve orbit to something that is buildable with our current materials. Therefore, though the bell is less efficient, it is good enough. Additionally the dual bell, which is almost as good as an aero spike, is preferable for an SSTO as it is easier to build and better understood.
According to Reaction Engines, "the SABRE will fly in 5 years." They said this just last year, 2017. . They also said this, verbatim, in 2011 . They also said this, with same meaning slightly different phrasing, in 1982 (they were also named differently then, but same people, same concept)
ahh yes, but i was just using the metric equivalent of 1 inch, 2.54cm, i used the sq to cut down on the text instead of saying 1 inch x 1 inch (2.54cm x 2.54cm ), although you are right and it could be stated as 6.45 cm sq
I hope someday Aerospikes are used for at least booster stages of rockets, they're design is awesome and I believe that if they are proven, going for a typical bell shape instead of a spike will be a thing of the past. Great video!
In vacuum, the spike doesn't really do anything for you that a lighter, more easily-cooled nozzle doesn't. An aerospike is good for a _sustainer_ stage like Atlas I's centre engine, though, or a single stage like VentureStar.
Quinsey Fritz No, no, no, the Aerospike should be used for upper stages and the bell nozzle used for the booster that gets the craft off the ground (sea level) till it reaches transonic speeds at high atlititude, then use aerospike enigines. That will make these engines practical application in the near future viable?
Again very well done. Your explanation is not only correct but moreover easy to understand by layman. You are also exactly correct in your assessment of why the aerospike engines havent caught on. I would recommend your videos to any college aerospace engineering students
I kind of miss the vocal call out to the video's shirt. Having a little text blurb just isn't the same as a science video audibly talking about rocket nozzle designs as well as the shirt the host is wearing.
Problem is that when I put things at the end of the video and I start the wind up most people leave and don't see them so moving the credits to the beginning might not be so dramatic but more people see it.
AJD OLD CHANNEL ARCHIVE The problem for me is I have dyslexia, i can read and write but I'm slow at it. Hearing things just help me. It would have been nice if my school could have been arsed helping me.
Aspect Sorry, mate, but that’s plain wrong. A square centimetre (cm^2) is, by definition, a square with sides of 1cm. A square with sides 2.54cm is 2.54^2cm^2 = 6.4516cm^2. You could, logically, call such a square a “2.54 centimetre square” but that is not the same thing as “2.54 square centimetres” and it’s probably not a good idea because of the potential for just this sort of confusion.
A point of disagreement. The reason for multi-stage rockets was not engine efficiency. It was weight reduction. They changed the shape of the output nozzle, but that was never reason for multiple stage rockets.
You just briefly touched on one aspect of the aerospike's disadvantage. The spike is heavy and long when properly designed, especially in the linear version. It's essentially a more manageable version of the vacuum bell nozzle's need to be infinitely long reducing the thrust/weight ratio. So they truncate it. But then you wind up with a low pressure zone past the squared off spike, reducing thrust. So you need to burn fuel there to fill in the gap, reducing max Isp.
Can foresee that 3D printing & design will eventually decrease the weight plus greatly improve efficiency, cooling & cost, just as it's making some improvements in conventional rocket design!
The J-2S engine (not the original J-2), which the aerospike engines talked about in this video were based on, used a tap-off cycle. Some of the combustion gases from the main chamber are tapped off to drive the turbopump. In the aerospike version, the gas that drives the pump is what's fed to the base of the spike, after it's done its work. No additional waste over the original engine: actually, you get some added benefit.
Just truncating the aerospike is a bad shape for the spike. To avoid a low pressure region they should have used a convex curvy ending. This harnesses the Coanda effect. en.wikipedia.org/wiki/Coanda_effect This might also avoid sharp edges. Usually sharp edges are bad for rocket engines.
John Bash-on-ger MrWombatty Sharp corners in airflows create turbulence, and turbulence leads to unstable flow - very bad for hypersonic rocket exhaust. 3D printing has a ways to go before recreating high-performance metal composite alloys, largely because there's no way to recreate the electronic structure required just by depositing atoms in a certain ratio. Forging, annealing, tempering, and quenching are centuries-old methods that accomplish this. I once worked a temp job at an alloy fabrication facility; look up Electronic Beam Deposition. That would be the starting point for a metal alloy 3D Printer.
HuntingTarg, , "3D printing" chemical structures has been used in electronics for decades with things like GaS devices. Making alloys of large-scale devices like rocket engine parts is likely something else.
Basicaly they make engine go soft enough to not waste power pushing through air, like walking gently enough on ice lake surface to provide propellent, but not too hard that your foot smashes through ice & then you start falling down.... & with different levels of surface strength depending on atmosphere pressure/height, just like different levels of lake ice surface strength depending on how thick its ice sheet is/depth. You know it's be easier if they just had a very big broad afterburner engine to ensure maximum softness/useful working thrust, & then just add a squeezing mechanism to close opening & increase thrust power if necessary...
This is brilliant. I never thought to ask why the exhaust plume widens out when the rocket is much higher (I think I thought it was because of fuel running out in that stage, or because the old lower stage took a while to separate). But thanks to your wonderful explanation it explains it fully, clearly, and logically.
Hidden until now, original voice recording from the launch of the Enterprise NCC-1701 as it reached the outer layer of the atmosphere: "Cap'n, she's breakin oop. We're loosin thrust man." "There's no time to lose Scotty. Engage the Aerospike"
I've heard that the biggest problem with aerospike engines is that they overheat very quickly. I think running cryogenic fuel through the surface like on the Space Shuttle would be a decent fix. I don't think anyones created an expander cycle aerospike engine yet, that would be interesting.
A single rocket is nice but most of the weight of a rocket is fuel and you need large tanks to hold that fuel. If you've burned out the fuel why do you continue to carry the large and heavy tanks. That's what staging is, dumping extra weight drastically increasing your fuel to acceleration ratio.
In a word im betting its cost. Its likely cheaper to build a bigger tank holding more fuel using a single or set of engines then it is to use many smaller tanks and engines as well as the equipment to eject them even considering the cost if fuel. Thats my guess anyway. I mean if 1 large tank and engine with extra fuel is $10,000 but requires 40% more fuel then the staged design which costs $30,000 even though its more efficent and uses less fuel then they will build the single large design. Another posibilty is reliability. When you seperate a rocket a lot can go wrong, a single engine and tank has fewer points it can fail vs say a 3 stage rocket. Indont know enough about rockets to say for sure but thats my best guesses
You're all forgetting the space shuttle. And someday we'll build another one.. this time one that isnt a huge boondoggle (the shuttle didnt meet its design goals, was more expensive to use than standard rockets etc etc)
Yes Paul, l’d like to see that too. Come on all you rocket boffins out there, show us the money, or is 50 million+ a day for NASA still not enough? Also, I’d like to see footage of one of these contraptions moving at the earth escape velocity of 17500 k/ph. All I’ve seen so far is them going at a very pedestrian pace out to sea.
You answered the question as to whether or not it'll be used in future yourself: Aerospikes will be used once the fuel becomes the biggest cost, just like modern aviation. We aren't there yet, but companies like Blue Origin and SpaceX are definitely going to get there, if all goes well.
I heard a rumor that the X-33 was absorbed by the DoD and was perfected. Supposedly, it launches out of Dugway test range, UT. It would not surprise me if there is a hybrid jet/rocket system used on the 'perfected' generations.
Not really, DOD was planning something called "Space Plane" if I recall. It was a small one-person vehicle that they could launch into LEO. Then, the pilot could observe, same as the Blackbird, but higher. They got further than VentureStar, being built around the same time, and had some similarities. Lifting body design. But I think DOD realized it was much cheaper to just use satellites for photos. That program eventually became X-37, which is purely robotic, no manned missions. It just serves as a testbed for testing new DOD toys in space. They still launch them once in a while.
there is one test atmospheric test flight using a cyclotron to create something that would have function similar to effect of an aerospike, Nokia tested an even dozen propulsion systems in bare hulls. The controls were too limited and used the control logic from a pin ball machine paddle controller, and spin up and spin down for Left Primary, Right Primary rotating in toward the center, three up and three down to control flow of hot gas. They use methane from liquid O2 and liquid H2 mixing in a combustion chamber, then the resulting water flows into a chamber with liquid N2, which is mixed with Ethanol liquid, to create liquid Methane about minus 180 c. They flew off the launch cradles and landed about twenty miles away. More like skied down the slope of the mountain when they came back towards the ground. So there has been large scale test, and it got ignored because all the satellites were on the 2004 summer Olympics in Russia. Finland being a very small population just buried the X37A under an avalanche, so no one would bother Finland for technology in case it was too advanced. A graduation class worth of MIT students and they build cell phones for everyone. I am looking forward to a working demonstrated F37B. The X37B was tested at cape canaveral this year. Though due to design I would not expect it to be a civilian space ship any time soon.
@@remliqa yep during the Olympics in Russia in 2004, they were trying to develop more commercial exports and the results of test got buried under the snow in an avalanche. the propulsion systems are likely still not a dead end just maybe not near mountains that are heavy with spring snow.
Hey moon, remember how we used to have a space shuttle program, and then during the bush years, that went away? Any excuse republicans have to make us dependent on the russians... /watch?v=NvS351QKFV4
I’ve seen so many benign videos downvoted that the only solution I can think of is that it’s bots and/or troll farms. Oh, and regular trolls too. Nothing like a video of a baby, puppy, and kitten with 400 downvotes. 🙄
Read the book The Moon Is A Harsh Mistress - Robert Heinlein. The Earth sits at the bottom of an 11 Km/s gravity well. the ultimate weapon system is being able to throw stones into it. An asteroid with very high metal content, measuring around 30 - 50 meters in diameter would hit the ground releasing the energy of a 20 megaton nuclear warhead, without radiation. A big stone in space shoved correctly on purpose, or by accident, could take out a city of millions years later. Who'd know who done it, or when it was pushed? We've seen space experts drop the ball and kill astronauts. We don't need these so called experts pushing stones around space and putting us all at risk. Especially responsibility shirking mining / drilling / energy corporations who's only interest is making money and pleasing shareholders. Who's going to set the rules, what nations will abide by them? who's going to make sure the rules are enforced? just how do you enforce them? who decides who can and who cannot mine, and who owns what asteroid? how do you claim an asteroid as yours? this is the stuff that starts wars.
@@climatechangefanclub7100 All those questions will get answered as they are faced by mankind. Asteroid mining is the financial incentive needed to turn humanity into a space-faring species.
I've always been fascinated by pulse detonation engines. Research was hindered because the materials required had simply not been invented yet, and of course computers were in their infancy so modelling wasn't possible. Still it would be quite incredible if someone developed a working engine based upon this principle.
Cameron Dufton - He didn't mention what fuel his hypothetical car uses. If your plug-in rechargeable electric car is charged from the solar energy, microhydroelectic, windmill plant that you own, the cost of fuel would be the depreciation and maintenance on your plant plus whatever the money would have done if you invested it instead of socking it into your home power plant, divided by the number of miles/kms your car goes before your plant is completely depreciated.
@@pnartg Except it goes beyond that and into the realm of hoarding. Any expense is considered unacceptable, regardless of the long-term benefits, financial or otherwise.
Right now the rocket itself is by far the most expensive part. Cutting the cost of the rocket is far more important than making a rocket more efficient. That is why SpaceX is trying to reuse rockets. It makes financial sense.
@@BXJ-mi9mm It makes financial sense in the long term, but your average bean counter believes that the only thing that matters is short-term quarterly gains. They don't believe in spending money in the short term to save money in the long term. That's why the average bean counter sucks at actually running businesses.
@@VestedUTuber Yes, that is true, but you need to focus on the most cost effective solutions first. Companies like SpaceX can't risk investing in completely new engines that may just slightly cut costs. By far the largest cost is the rocket itself. Companies like Boeing just want to make money off the government…
ARCA's project is a joke. They don't actually have an aerospike design and they're playing with peroxide as a fuel ... which I seriously doubt can generate the Isp to reach orbit. What surprises me is that you never mentioned Firefly Space Systems. Before abruptly loosing investor funding and going bankrupt in 2016, this company had a functioning toroidal aerospike engine on their test stand, which they were intending to use in a line of small-sat launchers. That engine used conventional LOX/RP-1 propellants.
lol you can reach orbit on peroxide as fuel......but it would results in a giant rocket with little payload and so, so many stages (I had to spec. one out once).
Great Video... I used to track the X33 program a long while ago, and always hoped the Aerospike engine technology would have lasted and been reused. Too bad it didn't make it (yet) into a new funded program. Thanks for the article as it explains the "why".
They were going to use an aerospike but went bust and the company which took over the assets dropped the aerospike and is going with conventional bell nozzles engines.
There's no point in a SSTO when/if you can land&reuse the rocket parts. That's really the only application where a spike engine really makes sense. But a SSTO is not efficient or low cost in itself. On the contrary. Next fail is that the thrust and thrust efficiency of a spike engine is limited by the cross section area. It's a better idea to have a small area for low drag and cover that end area with bell engines. Final fail is that many small engines are much lighter than a big engine, including a big spike engine (and many small spike engines nullify their supposed altitude adaption property through interference). And if you land the first stage, using thrustback, re-entry burn and landing burn, the weight saving on these rocket parts, through use of many small engines, end up being more fuel efficient than a spike engine anyway. And many small engines means you can mass produce them, which makes them much cheaper and more reliable. ...so...
Here is a good point for them. It makes us THINK about rockets and why we use what we have. The chance that something will work better makes us think, ponder, and calculate. Basically, I feel they exist for the discourse such as what we are having in this comment section. On second though, that is a rubbish point... My personal research is limited, as I have interests elsewhere (thank you TH-cam for the random video recommendation), but I see your points and believe them to be accurate.
Well SSTO means much simple and probably much cheaper design and on top of that will be fully reusable. Imagine a SSTO with aerospike engine launched from a platform hanging on giant balloons 35 km (or more) it'll deliver payload to low earth orbit almost 1:1 with the weight of the SSTO and of course it can land back to the platform.
The VentureStar was going to have _seven_ engines, not just one. The most ingenious part of its design was that it had a single structural fuel tank, because building one big fuel tank really is more efficient than building several smaller ones. The bigger the tank, the smaller the ratio of its empty weight to its internal volume. The VentureStar was essentially a flying fuel tank with engines, a payload bay, and a metallic heat shield for skin. Its mass ratio would have been insanely good if it hadn't been for the limits of early '90s material science.
So, could you theoretically apply the same sort of design criteria to ICE exhaust systems to make them as efficient as possible? I know some use a design extremely similar to current rocket exhausts, with the convergent point and the same expanded cone on the exit of that point. They have a name for it but I can't recall it currently.
@Curoius Droid - Why not launch a shuttle or other vehicle with wings instead of brute force against the air with a rocket ? And why not launch off the back of another larger vehicle like the X-1 did ? Is one way more efficient ? If the x-15 rocket plane went to the edge of space then how much further does it need to be for orbit ? Please do an episode on these things since I know many people wonder the same thing. Could the aerospike be working on some black project ? Or something BETTER ?
Don't even need a carrier aircraft when we have helium to take it to the tip of the atmosphere. Do you realize how much fuel it takes to lift the thing an inch off of the ground? Try picking it up an inch. You'll hurt your back.
I agree with you that using balloons would be the most cost & fuel efficient way to get spacecraft up to the edge of the atmosphere so they could be launched directly into space . Launches would cease to be the big media events that they can be afterward as they'd be fairly slow & probably take days to reach their altitude. However its still a good idea & makes me wonder why the aerospace industry haven't looked into this mode to getting vehicles into orbit
Helium can only take you to 30km above the Earth's surface or so. Some record altitude flights got to 50km. Low earth orbit is minimum 160km. Geostationary orbit is over 35,000km. For comparison's sake, here's an article between a helium balloon ride to space and a rocket ride to space for rich people. The helium balloon costs $75,000 per seat (6 seats so $450,000 to get a 10,000lbs (~4500kg) capsule to 30km). The more expensive rocket ride is $250,000 per seat (6 seats so $1.5M to get to 100km and probably much more mass given fuel density), while the less expensive rocket ride is $150,000 for a one seater. www.space.com/30750-world-view-space-tourism-balloon-flights.html Small satellites are over 1000kg, so If I use the carry capacity of that commercial helium balloon we only have 3500kg of mass left to build a rocket that can get our satellite from ~30km to LEO which I'm not convinced is particularly feasible. The use profile for helium balloons just isn't compatible with what rockets are used for. But that doesn't mean there aren't good use cases for them. You just need to use them for smaller things which won't go as high up.
@@ebrentprice9651 @Percy Barbarossa th-cam.com/video/dc8_AuzeYKE/w-d-xo.html th-cam.com/video/KerG4ILWEa4/w-d-xo.html Key concepts: Altitude isn't the primary energy constraint on getting into orbit; it's _getting up to orbital speed._ Balloons would reduce the weight requirements quite a bit, but in the end, you need a rocket to propel something into orbit even near the Karman line; you can't just lift a satellite up to an orbital altitude; it'll drop right back down to earth. Mass drivers (and Launch Loops, check out that video also: th-cam.com/video/J1MAg0UAAHg/w-d-xo.html ) reduce the weight requirements even further by imparting horizontal velocity, not simply altitude. "The same amount of rocket fuel, that will get you from the surface into Low Earth Orbit, will take you from Earth Orbit, almost anywhere in the Solar System." -Issac Arthur
@@VividBoricua The immediate problem with balloons are that they are stationary. The whole point of being in orbit is going fast enough at the particular altitude so that you're vehicle is falling at exact equivalent of the Earth's curve. If anything in orbit were to magically stop moving, it'd fall immediately. Gravity doesn't disappear a couple hundred miles above Earth. LEO requires a velocity of ~17,500 MPH to fall at the rate the Earth curves out from under you. It's not zero gravity. It's called micro-gravity and what looks like weightlessness is actually a freefall that just goes on and on. A balloon bringing a satellite as high as it could get would release it and watch it fall, probably break the sound barrier until the thickening atmosphere at lower altitudes slowed it down with friction a bit before it hit the ground like a angry little meteorite. Be cool to see though!
does the linear aerospike exhaust still provide high efficiency WITHOUT COMBUSTION?! I'm hoping that burning a fuel is not a requirement for the high efficiency. This does reduce the temperature of the assembly, and would be really useful for a project I'm researching. Honestly I can't find the answer to this question.
Wow this is really cool! Now I have an technology to use in my sci-fi universe that allows linear shaped propulsion engines instead of the classic circular shape. Thank you for this video. I hope real world companys will start to use the aerospike engine design, due to its efficiency. Also I mean it looks legit amazing.
When I was employed at Rocketdyne I worked on the design of this beautiful rocket engine!
That's what they call compartmentalization that's why your right hand never knows what your left hand is going to do with it and neither does anyone in it Bingo Homeland Security
I was on The Hill digging through a warehouse , probably ETEC, for some directed energy stuff and I look under a tarp.... HOLY CRAP a flippin linear aerospike just sitting there! Amazing. I climbed on top of it and poked around a bit, why not. I wonder where it went when everything was hauled off.
I was fine with developing the aerospike engine but the X-33/Venturestar was about developing far too many technologies in one demonstrator to expect success during the limited period of government financial support. It was too many eggs in one basket, they should've done something like the Delta Clipper with the option of a ring aerospike but designed for a conventional engine. The goal of establishing a crew launch vehicle should've been the main consideration given the complexities of the Shuttle and the obvious need to replace it.
You guys did some good work. I supported X-33 here and there in the 90’s a little. Too bad Lockheed tried to implement too many technology jumps in X-33. Being a shuttle tile engineer, i found it interesting LM was moving toward metallic TPS. Funny though, even LM abandoned the idea and are using ceramic tiles on their Orion capsule. Sierra Nevada is using ceramic tiles as well, and we hear Elon is moving toward ceramic TPS too. It would appear there isn’t anything better than the 60’s technology ceramic insulation for use on entry vehicles.
When i was employed with Skynet... we had bigger plans!
40% fuel saved does not means only fuel cost saved, it means less mass, nearly 40% less mass, so much more deltaV, much more utility mass.
true,that leads also in using just one aerospike engine instead of multiple engines in different stages,so also less weight for additional engines without also having the problem of dealing with returning stages.
Are you an engineer ?
@@Wrongway346 it is the very basis of rocket science: at the ignition the engine must lift all the rocket including all the fuel, so the consomption is higher. If you need to go at 200 km orbit for example, you need a powerfull enough engine, but now you need the fuel to feed it, and now you need a more powerfull engine, and more fuel, etc. The result is massive rockets with a mass/power ratio making posdible to reach the wanted orbit. So, an engine more efficient is extremely interesting, because less fuel means a big down sizing for the same purpose
also single stage spacecraft would mean no complex staging and less travel planning. You just need to actually pilot the ship towards your destination without timing every stage operation
@BRRP Yeah, I think it's easy for people to second guess what's being said. It sounds like the efficiency to mass savings calculation was already done. The engine probably isn't 40% more efficient, but even a marginal increase in efficiency rapidly pays dividends in rocketry.
After graduation (BS, MS engineering), I landed a job that partly fulfilled my dream to be an astronaut. Rocketdyne was then a division of Boeing. I went straight to advanced programs as a member of the XRS-2200 Engine, which is the Aerospike engine we see featured in this video. The X-33 faced a problem. The fuel tanks would not withstand the required fuel pressurization. Benefit to cost issues also started to make NASA lose interest. Yet, as the premier liquid engine propulsion in the World, Rocketdyne delivered. I had already jumped to Atlas and Delta propulsion, then the Space Shuttle Main Engine when I visited the test stand (B1, if I recall well) being set up for test at SSC. Extensive data was collected, and improvements in performance were noticed. These data will someday be helpful for an entity that is serious about the Aerospike. By the way, we need to encourage the newer generations to study science and engineering to keep the edge. God bless.
Thank you for not only your excellent work, but also your faith to give your upmost as an engineer to the Most High!
Unfortunately, with the break-down in society (specifically the highest, by-far, divorce rates in the world) kid's in the US no-longer have the schooling & home discipline, or even desire to pursue the hard sciences as they once did in your generation...Most military personnel in high command now consider this to be a national security concern 😰
@@gregsayles9253 Oh stop whining, Greg. Nobody wants to hear you complain.
Why is every problem related to flying engines is always "the developer went over budget"?
Because the people funding the projects care about cost and bottom lines, instead of science.
@Justin Rowe depends on why im investing. For profit sure. For the advancement of tech and our species, that shouldn't have a limit.
Check out the movie "Unacknowledged", might give you all a hint to what's actually going on.
Indeed money is important, but only because money = power to rule.
@@cpthindsight1894 that's obvious, it's a monetary system designed for class suppression. Debt is indentured servitude.
@Justin Rowe that's true. Even Elon musk is having to follow the most proven methods for space travel. Due to cost and profit. Regardless of how much he wants to develop new tech. He's still locked in the economic system.
There is a big Achilles Heel with the aerospike nozzle that is not talked about much in the technical literature...but is fundamental to fluid mechanics...
It has to do with the surface to volume ratio of any heat engine or nozzle...a big engine will always be more efficient than a small engine, all else being equal, due to the fact that internal surface area increases only by the square, while volume increases by the cube...
The surface area is where viscous losses occur [friction losses in the boundary layer of the flowing fluid at the wall]...while the volume is what determines mass flow, which determines power...
If you increase engine [or nozzle] size you decrease the surface to volume ratio which means less fluid comes in contact with the wall [in proportion to the mass flow], and your boundary layer is small compared to the volume and mass of fluid you are moving...
With the aerospike design you greatly increase the surface area for any given mass flow, compared to the standard bell [de Laval] nozzle...
You can see this by by looking at the two respective geometries...on a bell nozzle the sonic throat surface area is much smaller than on an aerospike 'toroidal' [axisymmetric] design...where the flow has to go around a donut-shaped center body in the middle of the flow...[also you now have two surfaces, an inner and outer, as opposed to just the outer surface of a de Laval sonic throat]
The result is that viscous losses will be much greater in the aerospike...thus increasing pressure loss through the nozzle...as more of the fluid has to 'scrub' against the donut surface...
Nozzle efficiency is directly a function of pressure loss...so you want to have as little pressure loss as possible...we recall from basic thermo that only pressure energy can be converted directly to work energy in a heat engine...so pressure is the 'coin of the realm' in any heat engine...
The 'linear' [2-D nozzle] aerospike concept is similarly bad in that respect, perhaps worse...you can see that you have, in effect, a whole bunch of little 'nozzles' lined up next to each other and directing the flow against the central 'spike'...
This is like having a whole bunch of tiny little nozzles, as opposed to one big nozzle...one big nozzle will always be more efficient for a given mass flow than a number of smaller nozzles...again for the fundamental principle of surface to volume and the resultant effect on viscous losses...
This is one of the reasons why the F1 engine was so effective...it had one huge nozzle...even though it had relatively low chamber pressure [about 1,000 psi...barely a quarter of what Russian high pressure engines achieve]
The difference in surface to volume ratio of an aerospike engine compared to a conventional nozzle would be at least an order of magnitude if not more...
That is one of the reasons we have not seen continued interest in the aerospike...it is fighting the laws of physics...
Another aspect that is not mentioned is chamber pressure...an engine with higher chamber pressure will be less sensitive to the losses that occur as a result of a flow that is not perfectly expanded at all flight regimes [ie altitudes]...
This is due to the fact that higher chamber pressure requires a larger nozzle area ratio...[the ratio of the exit area at the base of the bell to the sonic throat upstream]...
The higher your pressure, the longer the bell and the bigger its exit area...which means that the compromise at off-design ambient pressures will be less severe...ie you can select a bell length that can perform well [although not optimum] at varying altitude...
We saw this in the design of the hydrogen-fueled Shuttle main engines [RS25] which needed to work from launch to space...the engine achieves a chamber pressure of ~3,000 psi...using a fairly complex two-stage turbopump...
With the high pressure the nozzle was able to be sized as a good compromise at all altitudes and ambient pressures...from SL to space...
This is one of the reasons that Nasa concluded in the early 1980s that high pressure kerosene-fueled engines need to be developed...something the Soviets had already done in the 1960s with the NK33...
See Nasa technical report 19820002372
'Fuel/oxidizer-rich high-pressure preburners [staged-combustion rocket engine]'
However this has not happened...high pressure engines are not practical on the simple gas generator cycle which dumps the exhaust used to drive the turbopumps overboard...a staged combustion cycle is required...[as on the RS25 and all the Russian high pressure engines]
This, in turn, requires advanced turbopump capability...supposedly the BE4 engine in development now will use a staged cycle [with projected chamber pressure about half that of the Russian engines]...but SpaceX engines use the gas generator cycle and the company does not even make its own turbopumps [which are made by Barber-Nichols]...
Another issue with this video is that the single stage to orbit concept is tied in with the aerospike engine...which are really two independent ideas...
There are many different schemes and concepts for SSTO and the issue of nozzle performance is not even the major factor here...it is about the mass ratio...
We see this in the Tsiolkovsky rocket equation where delta v = specific impulse * gravity * natural log of mass ratio...
So we see from this relation that at a given engine ISP it's all about the mass ratio..ie the fundamental problem is still how to get enough fuel and oxidizer on board to get you to orbit in a single stage...
Even if you could make the nozzle more efficient by addressing the altitude problem it does not follow that you have solved the mass ratio problem...
Another point that is overlooked here is that any bell nozzle could conceivably achieve perfect expansion at any altitude IF the chamber pressure is somehow able to be varied...this gives the same result as changing the nozzle geometry to compensate for altitude...
For instance at SL launch we can use a lower chamber pressure to prevent overexpansion and increase pressure as we climb out to prevent underexpansion...
Of course this would be quite tricky for the turbopump as turbomachinery is also designed to have an optimum performance at a particular rotation speed and mass flow etc...
But the bottom line is that the aerospike is really a non-starter due to the viscous loss issue...and second, aerospike [or more broadly perfect nozzle expansion throughout the flight regime, however it is achieved] is in no way a 'solution' to the SSTO challenge...
Jet Guy - Cool read. Thanks for that. That's always the issue I had with the aerospike is that the expanding gas has too much to do before it actually generates thrust. So much lost energy through all the complexity. Bells for the win! I mean hell the aerospike doesn't even have the greatest isp. Jack of all trades master of none.
Jet Guy, Forty-five years after seeing that first photo of an aerospike on a test stand I've still never seen a proof-of-concept ballistic flight powered by an aerospike. The ground tests are so visually appealing that hard-boiled aerospace companies give the concept third chances. _Thanks for stating the flaw in the concept._ I'll still be on the lookout for that launch but more and more it looks like the flight realm may be confined to imagination.
Jet Guy - SSTO rockets must lift a lot of dead weight all the way to orbit, that multi stage rockets jettison after the fuel is consumed, improving the mass to thrust ratio each time a stage is jettisoned. Your very informative write-up indirectly states this, but for clarity, I state it directly.
Interesting thanks, food for thought, I am guessing there is a way around some of this within so called conventional physics, will be sleeping on this - many thought experiments as prelude to 'provoked' lucid dream states ;-)
Thanks again for your effort in describing this in good detail, hope you don't mind questions later on, cheers
Isn't it that you have more pressure at sea level and under expansion is the problem, with less at higher altitudes where overexpansion is the problem? Otherwise seemed very quite correct and obviously correct.
I love the way you present it, it looks like a mix of history class with engineering class
jordan couldn't have said it better! he beats all the network TV shows related to those topic's!
Good music too, nice to hear and not to distracting.
AwesomeBlackDude Flat Earther its called Mathematics!
AwesomeBlackDude can't you read? I meant you being a Flat Earther! because you are questioning how it was done that the van Allen belt was discovered. It is called mathematics!
Engineering history is best history!
Sometimes the internet gives you a random video and then you stumble upon this gem. Very informative, very clear explanation. Thank you, Sir!
It is good for near orbit.
if save 40% fuel w/ aerospike, doesn't that mean more payload?
People are pointing that out a lot in the comments and it would have been nice if Droid mentioned that in the video. That's less fuel needed plus you only use one engine means a much lighter vehicle. I don't know if it's enough to offset development costs, but it sounds worth looking into. That being said, these companies employ a lot of very smart people so it probably has been looked into and something about it doesn't look good enough to go after.
You also have to factor in mission flexibility of SSTO on a reusable craft. Faster turnaround and you can potentially land anywhere with a long enough runway.
much, much more payload. Weight of propelant is biggest issue with rocket
Doesnt necessarily mean more payload, it does mean that more of the mass the rocket launches with can be something other than fuel such as payload.
From a spy to a science presenter, you impress me Lord Varys.
You beat me to it...
Lmaoo
SPY MASTER!
He was a spy?
@@rimple1158 he is a eunuch
Black blackground is far more relaxing for eyes than white. Great change.
I 100% agree
Green screen reflection...
All that aside... Great mix of history and engineering...
russian bias confirmed
That depends on whether or not the white on the screen is reflective or emissive.
Subtle, aren't you?
It’s sad to think about how much aerospace technology was developed decades ago and not used since due to lack of financing.
with NASA funding being less than a fraction of US gdp, I bet that aint the issue... There's too much rich people spending money in useless luxury instead of funding useful science, useless wars and excessive expending, too much corporate lobbying... whatever. given the US government snail pace at funding space, it'll probably be private corporations to keep things going on, and other countries governments.
What makes you think it’s not still being used for current research and development? Just because NASA doesn’t show the public doesn’t mean they’re not still building spacecraft.
LazicStefan Man, you're fucking stupid.
FutureNow instead they waste money on gender studies because we dont know whos female and whos male.
LazicStefan Welfare? Really? That's what is sucking the money out of NASA? Couldn't possibly be the fact that our annual military budget is over $500 billion dollars.
Aerospike can still be used for non-SSTO rockets.
With SpaceX they can use it on the 1st stage part of the rocket and if the 2nd stage is needed to land then they can use the Aerospike on it as well.
Some crazy reusable rocket that lands in different atmospheres as part of a mission to multiple bodies in one trip, Aerospike is the way to go.
your manner of speaking is pleasant and easy to listen to.
you do show your face, which i normally find super annoying when other presenters do so, but you dont hog the camera with ego and you only demand our attention long enough to get across the desired relevant info; never stopping to attempt comedy or worthless sideshow spectacle .
great work, thank you.
I feel the same.
The primary reason for multistage rockets is not to allow for different engine nozzle sizes, it's to shed huge amounts of weight allowing for a far greater payload to orbit. An aero spike is less efficient in a multistage rocket, as it's worse at both sea level and in vacuum. Once above the atmosphere you don't need the same thrust you needed at sea level to get off the ground, you just need very efficient continued thrust to build up your orbital speed. An SSTO rocket is by design an inefficient way of getting to space, and with full booster reusability just a year or two down the road, SSTO can finally be put to rest.
PortlandPhil or both
Here's a video by Everyday Astronaut on why SSTOs suck: th-cam.com/video/Sfc2Jg1gkKA/w-d-xo.html
Where's my space elevator? Get it together, Elon!
Yes, that is very true.
We seem very biased to thinking of one-part vehicles. So we imagine hopping in our rocket and scooting into orbit 'cause that's like our everyday experience.
With chemical reactions, mutli-stage is the only practical choice. Nuclear propulsion is a different matter, but then we have other concerns...
Also, you might find this link interesting - jim-cantrell.squarespace.com/blog/2016/11/8/failure-is-the-seed-of-growth-for-success-lessons-learned-from-developing-and-testing-aerospike-rocket-engines
In particular, Jim states: "The point behind all this is that, while aerospike engines can provide performance advantages. The larger number of parts and components means that they are usually heavier than their regular bell-nozzle counterparts (in terms of thrust-to-weight) and, more importantly, require very high component reliability."
Consider a linear aerospike engine with 8 combustion chambers along each side -- that's 16 combustion chambers with attendant injectors, valves, controllers, ignitors, perhaps propellant pumps, and piping. Compare to a single chamber bell-nozzle design. Yes, the engine is more efficient at turning chemical energy into motion; however, the overall vehicle performance is worse.
You might want to look at the Linear aerospike stats. It was more efficient at sea level than a lot of standard boosters and as it rose became even more efficient and powerful when in orbit. There are some exceptions to this and they come from long term testing and design tweaking. If the linear aerospike had been in operation for all the same years I promise you it would have been improved to incredible levels by now.
Well I definitely use them in KSP to make SSTO's
This is one of the videos I would not expect you to be on. :) It always feels like an easter egg seeing you somewhere.
Also KSP = 💯
Is this just a hobby to you, or some way to eventually commercialize yourself that I haven't figured out yet? Will we eventually see Justin Y comments with "this comment was brought to you by Brilliant dot org. Sign up today with promo code Justin to....."
Thanks, but i'll stick to RAPIERs & Nervs
Muscle Hank would just throw things into orbit
So the answer is: Money
And bureaucracy
@@Ali-kp7bh no, I mean bureaucracy
It disgusts me that companies are too concerned with having maximum profits to make progress. That's all any business today cares about is maximum profit, getting every single penny they can squeeze out of something.
@@roselockecottage6486 not that simple. how you gonna fund your next launch? rockets are expensive, friend.
@@NaeroSpace corporations can afford it. They choose not to invest because they are only concerned with making *maximum* profit. If a huge profit can't be made they aren't interested and I find it gross.
Why looking at the price of fuel, when a kilo of fuel saved in efficiency, is a kilo gained payload?
Yes very true and that would be worth a lot more.
Troels Fischer Thomsen a kilo of fuel savings doesn't equate to an extra kilo of payload. It's not a 1:1 ratio
I think the more important factor is the rocket equation, fuel saving is really more than money, it's delta V
yeh i thought that was a stupid argument. Fuel efficiency doesn't mean you use less fuel, it means you use the same amount but get way more delta-V and therefor payload
Yes- weight is much less critical for the lower stages since they only undergo about a third of the acceleration. Fortunately the lower stages are the big, expensive ones and the easiest to recover. A reusable first stage is the low-hanging fruit, so it's nice to see SpaceX succeed at this.
Linear aerospike arrays look a lot like the Millennium Falcon's main engine...
George Lucas predicted it all !
Yeah lol ikr
Maybe Solo should learn what a parsec is.
The torodial aerospike engine looks like a naboo starfighter
@@nonamesupplied1875
See 'Solo - A Star-Wars Story' where parsecs are distance.
I think the main benefit of fuel efficiency isn't saving cost on fuel, but using that to have a higher payload rather than having to carry that much more weight in fuel, and at the end of the day the payload is what makes you money. If you can save several tons of fuel that is several tons of satellite you can send up.
Yes. Also if you need same mass delivered - less fuel means smaller fuel tanks, smaller rocket and less weight in general (which means it's easier to construct) and so on.
Bingo. All of that space/mass saved in fuel can be devoted to extra cargo.
crisray6789
Alqubier- Fronin spacecraft is the future of space craft technology, anything else is just spinning our wheels.
It's all about the mass fraction savings. SSTO isn't possible without improved efficiency. SpaceX is betting that the operational complexity of a fully recoverable TSTO solution will be "good enough" to truly open the skies. If they can hit their aspirational cost numbers, they'll be right... probably igniting an SSTO race to do to SpaceX what SpaceX is doing to ULA .
Google trends shows aerospike at 100 percent at October 1 after everyday astronaut's interview with Elon.
Actual science. Subscribed.
nice
i was nder the impression stages were additionally used to dispose of empty weight, being able to drop 75% of the fuel tank weight seemed like a good tradeoff to make
That's the major reason for staging, but you'd need a lot more fuel if you use an engine bell not optimized for the atmospheric pressure you're flying in. This is why when they fly Delta IIs with 9 boosters, only six are ignited at launch. The remaining three have engine bells optimized for higher altitudes, and are ignited later in flight. I'd assume that if they used aerospike engines (not that they'd work with solid propellant, but for the sake of the argument), they could get better efficiency out of each engine, and could afford to burn them longer with better average thrust across the entire flight, reducing the total weight and fuel required to get to orbit.
well said @thebigitchy, but they do work with solid propellants, at 9:15 of the video I mention the NASA test of a solid fuel toroidal aerospike, they should work on any chemical fuel engine that currently run on bell nozzles.
Had this video been made just ten years ago then there would have been a lot of head scratching about why nobody had taken the aero spike engine development further. However the latter part of this video introduces the commercial component to rocket launching. If the cost of development of the aero spike engine cannot be recouped against the backdrop of reusable traditional bell housing rocket engines then they will remain a ‘what might have been technology’; making them part of the X33 SSTO program put too many eggs in one basket. The linear aero spike engine does have desirable attributes from an operational and manufacturing view point due to its being essentially modular. Small repetitive combustion chambers are ideal candidates for mass production. The overall engine thrust is scaleable by simply varying the number of chambers. Cutting ignition to individual chambers effectively throttles the entire engine allowing reduction in thrust at max Q and booster landing. In many ways the annular arrangement of multiple engines as envisaged for SpaceX’ BFR booster creates a virtual aero spike.
I think that's an important point - especially if you're recovering your stages, staging counters most of the argument for areospikes. Yes, they are more efficient at a variety of altitudes, but they are less efficient at any one altitude. So, if you're staging *anyway*, there's less need to use an areospike. You can build your stages so that the loss of efficiency is minimal, getting most of the effect of areospikes without switching to an untested technology.
Areospikes are brilliant for single-stage-to-orbit designs - but there's lots of reasons not to use those designs in the first place, which areospikes don't counter.
@ Daniel Staal
The aerospike is the optimal engine for the first stage where the atmospheric pressure drops fast but for space work vacuum optimized bell engines are better.
Most people do not know, but to prevent the 'Bell' nozzles from melting, the nozzles have thin pipes in them, and the liquid fuel is vaporized as it goes through causing a refrigerant effect before the gas is sent into the nozzle to be burnt for thrust. This is the main reason we do not have thrust vectored engines like on the F22 Raptor, yet, as the mechanics required for vectoring, cooling and safety is very complicated, heavy and very expensive.
As they always say, referring to rocket engines, 'there is a million ways for it to go wrong and one way for it to go right'.
2D only. Then how does Russia have 3d thrust vectoring on the more reliable and cheaper su-35 in service for years? Seems they have this figured out.
@@tnix80 Are you really comparing an after burner engine that is on for a few seconds to a Rocket engine that is massively hotter and on non stop?
The Saturn V had thrust vectoring on the first stages, with regenerative cooling of the upper bell. The four outer engines all had thrust vectoring and that was in the mid-60s
@@Cheradanine Saturn V had gimbling, not even remotely close to true thrust vectoring.
There's just something mesmerizing about this guy's shirt on the jet black background. I can't tear my eyes away.
Great to see you and those shirts in colour again :)
RumpelForeskin color*
Christian Colour is the British spelling and so is correct.
Colour is correct. It’s English, us English invented the language.
Indeed!
Darren Bailey Actually it originally comes from the French.
The main reason that we use multiple stages on rockets is weight, not engine performance. An empty fuel tank is just dead weight, so you can as well just drop it. Using multi stage rockets saves a ton of fuel and also reduces the size of these things significantly.
Deus EXmachiA I think the other part of why staging is used is because the engine attached to the empty fuel tank has a significant mass as well.
If the engine wastes less fuel on an inefficient nozzle design, that might mean the rocket needs less fuel to go to the same altitude. That probably lowers the size and weight of the fuel tank, reducing the need to drop separate stages.
In old Soviet books on rockets I saw an interesting design where the rocket worked as a syringe. As it burned it got shorter and shorter and the excess tank walls just got burned or gradually dropped. This could be the next evolutionary step because it allows to go from a number of discrete stages to a continuous single stage. It also saves on engine weight.
Now add to this a variable shape nozzle and you got yourself an ideal chemical rocket.
+Ivan Bulanov
That sounds fantastic in both senses of the word.
It sounds like it could be amazing if done right...
...but it also sounds like a fantasy concept that would be impossible to implement.
I mean, if someone does find a way to make it work? Great! But I'm unconvinced that it can be done.
Damn the cost! Nasa needs to bring back the Venture Star program, re-vamped, with Space X as a partner. We need a shuttle replacement that works well!!
That was NASA's big mistake
That should be the title of your video : "Nasa's Big Mistake" Or maybe a Future Video??
I even built a hybrid electric/rocket plane, and called it "Future Star".
here is a link:
th-cam.com/video/J7f8hf8kgfg/w-d-xo.html
the space shuttle design is retardedly complicated compare to the design of the BFR. Plus NASA does not get the infinite cold war funding it had. The tech space x uses was already available but NASA does not have the capability to exploit it due to its retarded structure. Space x also has few competitor on the same level because of the Business mentality of "if it works, it's good enough".
SSTO like in science fiction wont happen until we make powerful and efficient energy sources and extremely efficient engines. Yet most of the planet is still fucking around with combustion engines and wind or inefficient solar energy like solar pannels
I saw the partially assembled X-33 in its abandoned hanger back in 2004. Crazy to see such a high tech machine abandoned and covered in owl shit. Making the fuel tanks in the shape necessary for that lifting body platform is just too complicated, and materials haven't changed much since then. It'd be interesting to see a conventional cylindrical rocket using them though.
Nope, NASA dodged a bullet.
First, the contract that NASA had with LockMart was a "prove it' contract, they got a fixed one billion dollar contract, if they exceeded that amount, LockMart had to eat it. They exceeded the billion dollars, LockMart had the nerve to ask NASA for more money and NASA said "Did you read the contract you signed?" By that time, LockMart wasn't going to do so and they stopped all work on the X-33, then a year later tried to hand it off to the USAF and they got laughed at. Why? Because...
Second, the X-33 was attempting to use technologies that had never been used for spacecraft, including composite laminate fuel tanks to save weight; and here's when things got ugly; during a tanking test of the X-33, when they were refilling the tanks with liquid nitrogen, one of the two tanks proceeded to split like an overcooked hot dog. This caused LockMart to consider adding metal fuel tanks to replace the composite laminate, which led to the issue that killed it.
Adding metal fuel tanks increased the weight of the X-33 to where it could not launch from the pad, it would have been too heavy-and that's when LockMart went to NASA and started begging, with NASA telling them to stick it and the USAF running away as fast as they could. And mind you, the X-33 was a quarter scale prototype, not a full scale one.
Don't blame NASA, blame LockMart.
I think multi stage rockets are the better way to go. As he said, bell nozzles are more efficient for specific atmosphere. But the big advantage of multi stage is that it sheds vehicle weight as you climb. Less weight, the better. Why do you want to continue to carry all that mass all the way into orbit if you don't need it? Also, once in orbit, you have to re-enter the atmosphere, and that is when you really want the smallest and lightest vehicle. Smaller re-entry vehicle means less shielding, and less weight means easier to land.
Bro, when you take away all those stages away, how much less fuel do you need? Those stages are literally just engines and fuel tanks, anything without stages is going weigh less, fact. I am not saying aerospikes are the way to go, I am saying your logic is flawed
I did a highschool report on the Venturestar/X-33 program. Got in touch with people at Lockheed Martin in the program and alot of cool goodies including a very detailed wood model. 😎
I was crushed when it was cancelled.😕
I was there at Lockheed Martin. We had just merged with Lockheed, I started at Martin Marietta. We were all excited about VentureStar, and I hoped to be able to test the flight software in my test lab. I was also crushed when it got canceled. The X-33 was the 53% scaled prototype that they actually built. But it had LOTS of problems - too many for one video.
I thought it was the coolest thing ever. They would have built it if they still had the courage that they did in the 1950s and 1960s. But we weren't competing against the Russians anymore, and NASA had become a bunch of misers, too cheap to actually build anything. Notice that there still isn't a replacement for the space shuttle, even today. They were planning on using Russian rockets because they were supposedly cheaper - how would that even work now.with Russia invading Ukraine? Then they wanted to strap Boeing Starliner on top of Russian rockets, and look how terribly the Starliner program is going - NASA doesn't want to pay for any mistakes or setbacks.
You can say it's about cost, but it's really about NASA not willing to spend money that they used to. Right now, America is willing to sit back and let China and India take over dominion of space. Until we find gold in space or have another space race, American leadership is space is ending.
That was unexpectedly informative. I don't know why this was recommended to me, but it was definitely worth my time.
word
It"s our common experience (that we just don't get how it ended up in our recommended video list) :)
Just a quick correction regarding 2:27: 1in² equals 6.45cm² (2.54² cm²).
2.54 centi-metres, 50 kilo-metres PLEASE! There is NO decimal prefix called a "ki-lom" and there is NO unit of length called an "etre"
How many decibels in a bushel again?
I wish I knew math lol
I think that the problem with aero spike engines in order for them to be successfully profitable is the size of the engines themselves. In all of the canceled projects that were using the engine (and all of the canceled uses of the engine in projects that were otherwise approved), your video shows that the aero spike engine that is being tested is HUGE in comparison to the engineers doing the testing. Bigger doesn't always mean better. Using multiple smaller sized aero spike engines instead of one big engine would probably prove to be more effective and more profitable. It might also prove to be safer if one of engines fails during testing, but the other engines keep working, the failed engine could be isolated and shut off until the test is over so that the engine could be examined afterwards to determine the cause of the failure. This would then help to minimize (if not prevent) disaster level accidents from occurring due to engine failure.
The aerospike was the only thing I liked about the Venturestar/X-33 project. I thought choosing that project was betting on too many high risk technologies at one time and they would've been better off focusing on proven technologies to get back into space which eventually is what we're doing now. My choice would've been the Delta Clipper just to get back into space then work on the technology demonstrators.
I've been fatally sick for 4 days clingy to life after being poisoned and your page helped me stay calm and get through it. I didn't even know I liked space. Thank you man just Thank you. I was so scared
Hey thanks guys I got out of the hospital and I am alive!
@emma harrington thank you I was suicidal and on drugs. I am no 3 months sober on 5/16/19. With out this his videos to keep my call I never would have made it to get the help I needed to get better.
Also ditching fuel tank weight as they empty kinda encourages multi-stage designs anyway. That reduces the range of altitudes an engine needs to work over.
Steven Clark That's a good point. Until this video, I'd thought it was dropping the empty weight, and making landing/recovery easier, that were the main reasons for multi-stage heavy lifters.
Steven Clark This is true, but dropping pieces of the rocket into the ocean means the rocket has to be rebuilt if used again. If the rocket is one piece and can be landed safely all you have to do is refuel it.
syaondri That sounds like it would work, although it would probably complicate other things.
_Sounds_ _Like_ _It_ _Would_ _Work:_ The USAF and USN have used detachable external fuel tanks on their fighters for decades. Even better, there's a certain type that bolts onto the airframe directly, called "conformal fuel tanks" because they're not the more traditional cigar-shaped pod hanging off the underside. My understanding is these CFT's are the best bet for extending a fighter's range, because not only do they let it carry more fuel, but they don't cause a lot of extra drag the way a more standard external tank does.
_Would_ _Probably_ _Complicate_ _Other_ _Things:_ The disadvantage of CFT's is they can't be dropped to shed weight and improve the plane's aerodynamics. Once they're on, they're on until the ground crew disconnects them. The reason is, the tanks are wired into the plane's fuel system, rather than keeping the internal fuel tank topped off like external fuel pods do. I'd imagine trying to shear off something that long and close to the fuselage - the CFT's on the F-15 are something like 20 feet long - would make flying really tricky, too, but that's mostly speculation. Either way, it would change the plane's balance and handling very suddenly, and rockets' failure rates are scary enough without adding more things that could suddenly decide to go squirrelly.
_Why_ _Consider_ _CFT's_ _At_ _All,_ _Then?_ Because big external tanks impose a _lot_ of extra drag. That means you need a bigger engine to toss the whole contraption into space, which means you need _more_ fuel, which means an *even* *bigger* engine, which means... And so on. Tsiolkovsy's rocket equation isn't complicated, as rocket science goes, but it is absolutely merciless.
All that said, I would not be surprised at all to learn that a group like SpaceX is working out the math so they can add extra fuel tanks that A) aren't also the engines themselves, like the STS and multi-stage rockets use, B) conform to the main rocket body such that they don't add horrible amounts of extra drag, and C) can be safely shed once they're empty. It's an engineering challenge, and rocket scientists are pretty good at that kind of thing. Here's hoping!
Internally-stored, ejectable fuel tanks? I had not thought of that, that's clever! Ditching the empties would change the center of gravity, but then, so does dropping the large external tanks, booster rockets, and empty stages currently in use, so that would happen either way. Yeah, the more I think of it, the more I like that idea.
And space guns! An engineer by the name of Gerald Bull was working on the idea of shooting payloads into orbit in the 1970's/80's, until the Israelis decided his practice of building cruise missiles and gigantic cannons for the Iraqi Hussein regime probably wasn't going to end well, and had him whacked. (...Well, we don't _know_ it was the Israelis: they certainly had a motive to bump off a weapons designer in Saddam's employ, but so did a lot of other people, like the Syrians, Iranians, South Africans, CIA, MI6, and a bunch of others. I guess building weapons is a dangerous job, for some reason.)
At the time, the big problem with Dr. Bull's design was that the shock of firing would be immediately lethal for any astronauts. A railgun's ability to spread the acceleration out beyond the immediate impulse seems like it could solve that, if you made the launch facility long enough.
And, of course, an orbital elevator would solve all these problems to the point of triviality. We just need to find or make something strong enough to reach that far under tension.
I very much wish to compliment you on the fine work that you do. Coming from a family whose dad was one of the early engineers in the early days of the space and missile programs for the United States, I very seldom see any presentations that are more than conjecture with little fact based. You are an outstanding representative of what a presentation should be, and have done your research quite well with the ability to throw out the gossip and rumor mail base facts and purely discuss and present the real scientific based evidence on every program you present
TH-cam recommendations finally got it right. Great video.
yeah, much better as "Pussy-Shaving/Waxing"!
It's kind of depressing in its way
@@MrP71 wut
I remember reading about these in the late 60's I think. Always wondered why I never heard about them again.
My first impression of your videos was, "This looks and sounds professional." You just got a new subscriber!
I don't know who this guy is but like his shirts, his vlogs are really entertaining , fresh and new. Hats off!
so this is rocket science
I'm not surprised if I don't understand
@2:35 Whilst it's true that we have evolved to live at (more or less) one standard atmosphere, and we can't survive for too long if that poressure is reduced to about half that, that is not the reason we don't feel atmospheric pressure. If we truly did have a net pressure of 14.5 pounds bearing down on every square inch of our body, then trust me, we would really, really feel that.
That actual reason why we don't feel atmospheric pressure, is that our bodies are permeable. That is there is 14.5 PSI pushing outwards which makes the net pressure on any point of our body zero. That's also how commercials divers have descended to 500 metres where the pressure can reach 700 PSI.
That's not so say that there aren't physiological issues due to the differences in partial pressure of gases. Those who are diving to considerable depths have to use special mixes of gases to avoid the toxic effects of normal gas mixes at high pressure, but they don't actually "feel" the pressure due to that internal and external equalisation.
I thought we use staged rocket design because of the weight issue
Yep. That's the real reason. It allows us to use better optimized engines, but that's not the real reason. The rocket equation necessitates enormous mass ratios to get high changes in velocity, especially for orbit. There are limits, however, to how light a fuel tank can be. To circumvent this, we can put a separate fuel tank on top, with its own engines. This lets us cheat and get a higher effective mass ratio.
Thats one of the reasons
5wwweeedxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx za q za
You could have a segmented fuel tank that ejects it's empty components, which parachute down and can be reused.
Well, the initial stage is fully capable to lift the entire mass of the rocket, but at a plain acceleration ratio, to increase the TWR (thrust/weight ratio) the rocket needs to loose mass while accelerating. So, both are the reasons for staging. Try it with Kerbal Space Program game hehehhe
I think this is perhaps the best description of how atmospheric pressure affects rocket engines.
Thank you for helping me to understand this.
When you mentioned that it was "quite simple" I thought "I'm sure not going to understand it now", however you explained it very well so that even I could understand it.
We stage mainly because of the mass ratio. Staging reduces the required mass ratio to achieve orbit to something that is buildable with our current materials. Therefore, though the bell is less efficient, it is good enough. Additionally the dual bell, which is almost as good as an aero spike, is preferable for an SSTO as it is easier to build and better understood.
Hopefully SABREs will be an option within the next decade as well.
According to Reaction Engines, "the SABRE will fly in 5 years."
They said this just last year, 2017.
.
They also said this, verbatim, in 2011
.
They also said this, with same meaning slightly different phrasing, in 1982
(they were also named differently then, but same people, same concept)
1sq inch is actually 6.4516 cm² or 2.54² cm²
ahh yes, but i was just using the metric equivalent of 1 inch, 2.54cm, i used the sq to cut down on the text instead of saying 1 inch x 1 inch (2.54cm x 2.54cm ), although you are right and it could be stated as 6.45 cm sq
As ihsan said we are happy for the videos you make. I just wanted to point of the small mistake. No blame no flame.
Curious Droid just put a correction. Everyone makes mistakes, not everyone fixes them.
We're also the major players. How's your space program going?
Ricardo's country's space program is a tall ladder
I hope someday Aerospikes are used for at least booster stages of rockets, they're design is awesome and I believe that if they are proven, going for a typical bell shape instead of a spike will be a thing of the past.
Great video!
arca space is building a aerospike rocket
www.arcaspace.com/
In vacuum, the spike doesn't really do anything for you that a lighter, more easily-cooled nozzle doesn't. An aerospike is good for a _sustainer_ stage like Atlas I's centre engine, though, or a single stage like VentureStar.
Quinsey Fritz No, no, no, the Aerospike should be used for upper stages and the bell nozzle used for the booster that gets the craft off the ground (sea level) till it reaches transonic speeds at high atlititude, then use aerospike enigines. That will make these engines practical application in the near future viable?
Corey Taylor. www.AdamtheWoo.com , has in his travels across the USA, explored an old factory that was trying to build these aerospike rocket engines.
Arca looks like total vaporware and seems pretty unlikely to ever fly.
Again very well done. Your explanation is not only correct but moreover easy to understand by layman. You are also exactly correct in your assessment of why the aerospike engines havent caught on. I would recommend your videos to any college aerospace engineering students
I kind of miss the vocal call out to the video's shirt. Having a little text blurb just isn't the same as a science video audibly talking about rocket nozzle designs as well as the shirt the host is wearing.
Problem is that when I put things at the end of the video and I start the wind up most people leave and don't see them so moving the credits to the beginning might not be so dramatic but more people see it.
jodudeit I totally agree.
Wow... some people have some pretty incredible priorities in life!
AJD OLD CHANNEL ARCHIVE The problem for me is I have dyslexia, i can read and write but I'm slow at it. Hearing things just help me. It would have been nice if my school could have been arsed helping me.
2:25 "1 square inch, or 2.54 square cm". 1 square inch is 6.4516 square centimeters.
2.54 squared is 6.4516
You would sad 2.54 square cm for the area of square with the side length of 2.54cm. You wouldn't actually use the squared value of 2.54
@@aspct. A square by definition is all equal sides, so squaring the value is accurate for this example. You are correct, my good sir!
@@aspct. If you say make a square of 3x3 inches it is 9 square inches. If you make a square of 2.54x2.54 cm it is 6.4516 square cm ....
Aspect
Sorry, mate, but that’s plain wrong. A square centimetre (cm^2) is, by definition, a square with sides of 1cm.
A square with sides 2.54cm is 2.54^2cm^2 = 6.4516cm^2.
You could, logically, call such a square a “2.54 centimetre square” but that is not the same thing as “2.54 square centimetres” and it’s probably not a good idea because of the potential for just this sort of confusion.
A point of disagreement. The reason for multi-stage rockets was not engine efficiency. It was weight reduction. They changed the shape of the output nozzle, but that was never reason for multiple stage rockets.
He knows that he said it was ONE of the major reasons
dont see how thrust is vectored, how additional thrust is obtained or how heat is moved away from the exhaust. nice name, though
"Aye, that'll give 'er thrust!"
-- _Chicken Run_
Dan Black yes
Love that movie... :)
spoken by a true inventor
Got me to chuckle!
Thrrrruuuuusssst
They look like something straight out of a sci-fi film. I prefer the linear versions, they look awesome.
The linear aero spike engine seems so like the next step that should be taken.
Glad you’re feeling better, miss your videos mate, I hope you keep it up, this video is very good
You just briefly touched on one aspect of the aerospike's disadvantage. The spike is heavy and long when properly designed, especially in the linear version. It's essentially a more manageable version of the vacuum bell nozzle's need to be infinitely long reducing the thrust/weight ratio. So they truncate it. But then you wind up with a low pressure zone past the squared off spike, reducing thrust. So you need to burn fuel there to fill in the gap, reducing max Isp.
Can foresee that 3D printing & design will eventually decrease the weight plus greatly improve efficiency, cooling & cost, just as it's making some improvements in conventional rocket design!
The J-2S engine (not the original J-2), which the aerospike engines talked about in this video were based on, used a tap-off cycle. Some of the combustion gases from the main chamber are tapped off to drive the turbopump. In the aerospike version, the gas that drives the pump is what's fed to the base of the spike, after it's done its work. No additional waste over the original engine: actually, you get some added benefit.
Just truncating the aerospike is a bad shape for the spike.
To avoid a low pressure region they should have used a convex curvy ending.
This harnesses the Coanda effect.
en.wikipedia.org/wiki/Coanda_effect
This might also avoid sharp edges. Usually sharp edges are bad for rocket engines.
John Bash-on-ger
MrWombatty
Sharp corners in airflows create turbulence, and turbulence leads to unstable flow - very bad for hypersonic rocket exhaust.
3D printing has a ways to go before recreating high-performance metal composite alloys, largely because there's no way to recreate the electronic structure required just by depositing atoms in a certain ratio. Forging, annealing, tempering, and quenching are centuries-old methods that accomplish this.
I once worked a temp job at an alloy fabrication facility; look up Electronic Beam Deposition. That would be the starting point for a metal alloy 3D Printer.
HuntingTarg, , "3D printing" chemical structures has been used in electronics for decades with things like GaS devices. Making alloys of large-scale devices like rocket engine parts is likely something else.
Only KSP players know the Kerbodyne
vive la ks-25 vector engines
It’s my 3rd stage
Long live jeb's junkyard!!!
Just strap on more boosters and don't forget the space tape! Remember to take your poodle with you for kerbin system orbit and transfers.
@@christopherpittman8054 meh, I prefer the wolfhound
Basicaly they make engine go soft enough to not waste power pushing through air, like walking gently enough on ice lake surface to provide propellent, but not too hard that your foot smashes through ice & then you start falling down....
& with different levels of surface strength depending on atmosphere pressure/height, just like different levels of lake ice surface strength depending on how thick its ice sheet is/depth.
You know it's be easier if they just had a very big broad afterburner engine to ensure maximum softness/useful working thrust, & then just add a squeezing mechanism to close opening & increase thrust power if necessary...
This is brilliant. I never thought to ask why the exhaust plume widens out when the rocket is much higher (I think I thought it was because of fuel running out in that stage, or because the old lower stage took a while to separate). But thanks to your wonderful explanation it explains it fully, clearly, and logically.
Everyday astronaut is talking all the time about his upcoming video about this and now this one gets recommended
daniel_960_ It’s really odd , i only clicked on this video because of his mention about aero spike engines during the new Starship presentation
When someone says 'It's not rocket science' in aerodynamics 101, and everyone gives them the death stare.
WHOOOSH!
but it is not rocket science....
Hidden until now, original voice recording from the launch of the Enterprise NCC-1701 as it reached the outer layer of the atmosphere:
"Cap'n, she's breakin oop. We're loosin thrust man."
"There's no time to lose Scotty. Engage the Aerospike"
I've heard that the biggest problem with aerospike engines is that they overheat very quickly. I think running cryogenic fuel through the surface like on the Space Shuttle would be a decent fix. I don't think anyones created an expander cycle aerospike engine yet, that would be interesting.
I suppose with the SpaceX business model, with the reusable first stage.
This reduces / eliminates the need for a one engine for all
Uncle Fester knows his rocket science!
And has a great tailor!
Nah man he's the man from Who's Line is it Anyways. Lol
Damn!!! That shirt is louder then a rocket engine.
my favourite youtube channel. It always feels like listen to bedtime stories for adults with an interest for science
A single rocket is nice but most of the weight of a rocket is fuel and you need large tanks to hold that fuel. If you've burned out the fuel why do you continue to carry the large and heavy tanks. That's what staging is, dumping extra weight drastically increasing your fuel to acceleration ratio.
In a word im betting its cost. Its likely cheaper to build a bigger tank holding more fuel using a single or set of engines then it is to use many smaller tanks and engines as well as the equipment to eject them even considering the cost if fuel.
Thats my guess anyway. I mean if 1 large tank and engine with extra fuel is $10,000 but requires 40% more fuel then the staged design which costs $30,000 even though its more efficent and uses less fuel then they will build the single large design.
Another posibilty is reliability. When you seperate a rocket a lot can go wrong, a single engine and tank has fewer points it can fail vs say a 3 stage rocket. Indont know enough about rockets to say for sure but thats my best guesses
@@arcticfox5118 Don't forget the cost to retrofit all of your existing flight vehicles to accommodate it.
@@arcticfox5118 the problem is weight. You need to discard useless masses as soon as possible. So, aero-spike ends in an useless concept.
Fuel is cheap, hardware isn't.
You're all forgetting the space shuttle. And someday we'll build another one.. this time one that isnt a huge boondoggle (the shuttle didnt meet its design goals, was more expensive to use than standard rockets etc etc)
Show me just 1 x of any rocket motor in a 10x -7 vacuum, any link? Any vacuum testing of any rocket motor? Thanks.
Yes Paul, l’d like to see that too. Come on all you rocket boffins out there, show us the money, or is 50 million+ a day for NASA still not enough? Also, I’d like to see footage of one of these contraptions moving at the earth escape velocity of 17500 k/ph. All I’ve seen so far is them going at a very pedestrian pace out to sea.
You answered the question as to whether or not it'll be used in future yourself: Aerospikes will be used once the fuel becomes the biggest cost, just like modern aviation. We aren't there yet, but companies like Blue Origin and SpaceX are definitely going to get there, if all goes well.
1980s = new technology...
Who would have thought that the space industry was the most outdated..
It's not lol, it's just under cover while the rest of us worry about a fake virus.
@@SuperDirtPig
You deserved a like for being woke
@@SuperDirtPig what are you smoking? I want some.
very well presented/hosted/narrated---brilliant video!
Well done per usual
I heard a rumor that the X-33 was absorbed by the DoD and was perfected. Supposedly, it launches out of Dugway test range, UT. It would not surprise me if there is a hybrid jet/rocket system used on the 'perfected' generations.
Not really, DOD was planning something called "Space Plane" if I recall. It was a small one-person vehicle that they could launch into LEO. Then, the pilot could observe, same as the Blackbird, but higher. They got further than VentureStar, being built around the same time, and had some similarities. Lifting body design. But I think DOD realized it was much cheaper to just use satellites for photos.
That program eventually became X-37, which is purely robotic, no manned missions. It just serves as a testbed for testing new DOD toys in space. They still launch them once in a while.
there is one test atmospheric test flight using a cyclotron to create something that would have function similar to effect of an aerospike, Nokia tested an even dozen propulsion systems in bare hulls. The controls were too limited and used the control logic from a pin ball machine paddle controller, and spin up and spin down for Left Primary, Right Primary rotating in toward the center, three
up and three down to control flow of hot gas. They use methane from liquid O2 and liquid H2 mixing in a combustion chamber, then the resulting water flows into a chamber with liquid N2, which is mixed with Ethanol liquid, to create liquid Methane about minus 180 c. They flew off the launch cradles and landed about twenty miles away. More like skied down the slope of the mountain when they came back towards the ground. So there has been large scale test, and it got ignored because all the satellites were on the 2004 summer Olympics in Russia. Finland being a very small population just buried the X37A under an avalanche, so no one would bother Finland for technology in case it was too advanced. A graduation class worth of MIT students and they build cell phones for everyone. I am looking forward to a working demonstrated F37B. The X37B was tested at cape canaveral this year. Though due to design I would not expect it to be a civilian space ship any time soon.
Wait.. Nokia tested rocket engines?
@@remliqa yep during the Olympics in Russia in 2004, they were trying to develop more commercial exports and the results of test got buried under the snow in an avalanche. the propulsion systems are likely still not a dead end just maybe not near mountains that are heavy with spring snow.
Watching this to prepare for everyday astronaut's vid coming soon lol, great video
Same here.
How can you dislike a video like this???
Vincent GR cus muh Holy book says so👽=😈 LoL
Flat earthers
M.r. Moon
Dude, stop it with the political opinions on an informational video!
Hey moon, remember how we used to have a space shuttle program, and then during the bush years, that went away? Any excuse republicans have to make us dependent on the russians... /watch?v=NvS351QKFV4
I’ve seen so many benign videos downvoted that the only solution I can think of is that it’s bots and/or troll farms. Oh, and regular trolls too. Nothing like a video of a baby, puppy, and kitten with 400 downvotes. 🙄
BTW, even Leonardo Da Vinchi drew hypothetical diagrams of bell engines. He was ahead of his time in many ways.
Little mistake: 1 square inch is 6.45 square cm. You misstook length conversion for square measure conversion.
not so little mistake when talking about space. Remember Mars Climate Orbiter ? Crashed because of a conversion error
This guy is great, education in such an entertaining way
He should cover statistics, calculus and topology.
Would love to see one by you folks on asteroid prospecting and harvesting/mining.
Read the book The Moon Is A Harsh Mistress - Robert Heinlein. The Earth sits at the bottom of an 11 Km/s gravity well. the ultimate weapon system is being able to throw stones into it. An asteroid with very high metal content, measuring around 30 - 50 meters in diameter would hit the ground releasing the energy of a 20 megaton nuclear warhead, without radiation. A big stone in space shoved correctly on purpose, or by accident, could take out a city of millions years later. Who'd know who done it, or when it was pushed? We've seen space experts drop the ball and kill astronauts. We don't need these so called experts pushing stones around space and putting us all at risk. Especially responsibility shirking mining / drilling / energy corporations who's only interest is making money and pleasing shareholders. Who's going to set the rules, what nations will abide by them? who's going to make sure the rules are enforced? just how do you enforce them? who decides who can and who cannot mine, and who owns what asteroid? how do you claim an asteroid as yours? this is the stuff that starts wars.
@@climatechangefanclub7100 All those questions will get answered as they are faced by mankind. Asteroid mining is the financial incentive needed to turn humanity into a space-faring species.
I've always been fascinated by pulse detonation engines. Research was hindered because the materials required had simply not been invented yet, and of course computers were in their infancy so modelling wasn't possible. Still it would be quite incredible if someone developed a working engine based upon this principle.
You look like the 'outstanding move' guy.
Yes he does
Perfect presentation. congrats and thank you!
Yep which is more expensive buying a car or refueling it?
Depends on the price of the car, the price of fuel, the fuel efficiency of the car and the cost of maintaining the car.
jojo Smith if cars still need run on oil based fuel
Cameron Dufton - He didn't mention what fuel his hypothetical car uses.
If your plug-in rechargeable electric car is charged from the solar energy, microhydroelectic, windmill plant that you own, the cost of fuel would be the depreciation and maintenance on your plant plus whatever the money would have done if you invested it instead of socking it into your home power plant, divided by the number of miles/kms your car goes before your plant is completely depreciated.
Cameron Dufton - Maintenance cost is not part of the purchase cost of a car unless the purchase cost includes a lifetime maintenance contract.
Al Grayson maintenance is optional, just like refueling. They are both costs that need to be factored in if you want to do a realistic comparison.
Damn... this would have been so cool and futuristic looking. Hoping someone brings it to fruition.
Another shinning example were in an outstanding idea was not followed up on due to "Bean Counter".
If you only have so many beans in your budget somebody better be counting them to make sure you don't run out before you get to launch.
@@pnartg
Except it goes beyond that and into the realm of hoarding. Any expense is considered unacceptable, regardless of the long-term benefits, financial or otherwise.
Right now the rocket itself is by far the most expensive part. Cutting the cost of the rocket is far more important than making a rocket more efficient. That is why SpaceX is trying to reuse rockets. It makes financial sense.
@@BXJ-mi9mm
It makes financial sense in the long term, but your average bean counter believes that the only thing that matters is short-term quarterly gains. They don't believe in spending money in the short term to save money in the long term.
That's why the average bean counter sucks at actually running businesses.
@@VestedUTuber Yes, that is true, but you need to focus on the most cost effective solutions first. Companies like SpaceX can't risk investing in completely new engines that may just slightly cut costs. By far the largest cost is the rocket itself.
Companies like Boeing just want to make money off the government…
ARCA's project is a joke. They don't actually have an aerospike design and they're playing with peroxide as a fuel ... which I seriously doubt can generate the Isp to reach orbit.
What surprises me is that you never mentioned Firefly Space Systems. Before abruptly loosing investor funding and going bankrupt in 2016, this company had a functioning toroidal aerospike engine on their test stand, which they were intending to use in a line of small-sat launchers. That engine used conventional LOX/RP-1 propellants.
lol you can reach orbit on peroxide as fuel......but it would results in a giant rocket with little payload and so, so many stages (I had to spec. one out once).
@@DanielScutt more like makes sense for a student project with a very over protective safety department
Never under estimate the power of farts as propellant
Good Video dude. Your very good and explaining complex subject matter.
@joe santo there were a lot of holes....
Great Video... I used to track the X33 program a long while ago, and always hoped the Aerospike engine technology would have lasted and been reused. Too bad it didn't make it (yet) into a new funded program. Thanks for the article as it explains the "why".
9:01 can not be unseen...
What, you mean the giant aluminum scrotum?
jjohnston94 yes dem ballz ⚽
Isn't Firefly rocket's first stare using an aerospike?
They were going to use an aerospike but went bust and the company which took over the assets dropped the aerospike and is going with conventional bell nozzles engines.
Curious Droid Don't say it's true :( They were close!
There's no point in a SSTO when/if you can land&reuse the rocket parts. That's really the only application where a spike engine really makes sense. But a SSTO is not efficient or low cost in itself. On the contrary. Next fail is that the thrust and thrust efficiency of a spike engine is limited by the cross section area. It's a better idea to have a small area for low drag and cover that end area with bell engines. Final fail is that many small engines are much lighter than a big engine, including a big spike engine (and many small spike engines nullify their supposed altitude adaption property through interference). And if you land the first stage, using thrustback, re-entry burn and landing burn, the weight saving on these rocket parts, through use of many small engines, end up being more fuel efficient than a spike engine anyway. And many small engines means you can mass produce them, which makes them much cheaper and more reliable. ...so...
Here is a good point for them. It makes us THINK about rockets and why we use what we have. The chance that something will work better makes us think, ponder, and calculate. Basically, I feel they exist for the discourse such as what we are having in this comment section. On second though, that is a rubbish point...
My personal research is limited, as I have interests elsewhere (thank you TH-cam for the random video recommendation), but I see your points and believe them to be accurate.
Well SSTO means much simple and probably much cheaper design and on top of that will be fully reusable. Imagine a SSTO with aerospike engine launched from a platform hanging on giant balloons 35 km (or more) it'll deliver payload to low earth orbit almost 1:1 with the weight of the SSTO and of course it can land back to the platform.
The VentureStar was going to have _seven_ engines, not just one. The most ingenious part of its design was that it had a single structural fuel tank, because building one big fuel tank really is more efficient than building several smaller ones. The bigger the tank, the smaller the ratio of its empty weight to its internal volume. The VentureStar was essentially a flying fuel tank with engines, a payload bay, and a metallic heat shield for skin. Its mass ratio would have been insanely good if it hadn't been for the limits of early '90s material science.
So, could you theoretically apply the same sort of design criteria to ICE exhaust systems to make them as efficient as possible? I know some use a design extremely similar to current rocket exhausts, with the convergent point and the same expanded cone on the exit of that point. They have a name for it but I can't recall it currently.
@Curoius Droid - Why not launch a shuttle or other vehicle with wings instead of brute force against the air with a rocket ? And why not launch off the back of another larger vehicle like the X-1 did ?
Is one way more efficient ?
If the x-15 rocket plane went to the edge of space then how much further does it need to be for orbit ?
Please do an episode on these things since I know many people wonder the same thing.
Could the aerospike be working on some black project ? Or something BETTER ?
Don't even need a carrier aircraft when we have helium to take it to the tip of the atmosphere. Do you realize how much fuel it takes to lift the thing an inch off of the ground? Try picking it up an inch. You'll hurt your back.
I agree with you that using balloons would be the most cost & fuel efficient way to get spacecraft up to the edge of the atmosphere so they could be launched directly into space . Launches would cease to be the big media events that they can be afterward as they'd be fairly slow & probably take days to reach their altitude. However its still a good idea & makes me wonder why the aerospace industry haven't looked into this mode to getting vehicles into orbit
Helium can only take you to 30km above the Earth's surface or so. Some record altitude flights got to 50km. Low earth orbit is minimum 160km. Geostationary orbit is over 35,000km.
For comparison's sake, here's an article between a helium balloon ride to space and a rocket ride to space for rich people. The helium balloon costs $75,000 per seat (6 seats so $450,000 to get a 10,000lbs (~4500kg) capsule to 30km). The more expensive rocket ride is $250,000 per seat (6 seats so $1.5M to get to 100km and probably much more mass given fuel density), while the less expensive rocket ride is $150,000 for a one seater.
www.space.com/30750-world-view-space-tourism-balloon-flights.html
Small satellites are over 1000kg, so If I use the carry capacity of that commercial helium balloon we only have 3500kg of mass left to build a rocket that can get our satellite from ~30km to LEO which I'm not convinced is particularly feasible.
The use profile for helium balloons just isn't compatible with what rockets are used for. But that doesn't mean there aren't good use cases for them. You just need to use them for smaller things which won't go as high up.
@@ebrentprice9651 @Percy Barbarossa
th-cam.com/video/dc8_AuzeYKE/w-d-xo.html
th-cam.com/video/KerG4ILWEa4/w-d-xo.html
Key concepts:
Altitude isn't the primary energy constraint on getting into orbit; it's _getting up to orbital speed._ Balloons would reduce the weight requirements quite a bit, but in the end, you need a rocket to propel something into orbit even near the Karman line; you can't just lift a satellite up to an orbital altitude; it'll drop right back down to earth.
Mass drivers (and Launch Loops, check out that video also: th-cam.com/video/J1MAg0UAAHg/w-d-xo.html ) reduce the weight requirements even further by imparting horizontal velocity, not simply altitude.
"The same amount of rocket fuel, that will get you from the surface into Low Earth Orbit, will take you from Earth Orbit, almost anywhere in the Solar System." -Issac Arthur
@@VividBoricua The immediate problem with balloons are that they are stationary. The whole point of being in orbit is going fast enough at the particular altitude so that you're vehicle is falling at exact equivalent of the Earth's curve. If anything in orbit were to magically stop moving, it'd fall immediately. Gravity doesn't disappear a couple hundred miles above Earth. LEO requires a velocity of ~17,500 MPH to fall at the rate the Earth curves out from under you. It's not zero gravity. It's called micro-gravity and what looks like weightlessness is actually a freefall that just goes on and on. A balloon bringing a satellite as high as it could get would release it and watch it fall, probably break the sound barrier until the thickening atmosphere at lower altitudes slowed it down with friction a bit before it hit the ground like a angry little meteorite. Be cool to see though!
@Curious Droid Just out of curiosity, have you ever played Kerbal Space Program?
white forest whitaker really knows what he's talking about
does the linear aerospike exhaust still provide high efficiency WITHOUT COMBUSTION?! I'm hoping that burning a fuel is not a requirement for the high efficiency. This does reduce the temperature of the assembly, and would be really useful for a project I'm researching. Honestly I can't find the answer to this question.
Wow this is really cool! Now I have an technology to use in my sci-fi universe that allows linear shaped propulsion engines instead of the classic circular shape. Thank you for this video. I hope real world companys will start to use the aerospike engine design, due to its efficiency. Also I mean it looks legit amazing.