Aerospike Engines - Why Aren't We Using them Now?

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This is a very fascinating subject, but apathy reigns as per usual on JPP.

[Frank Apisa]

Maybe if you included some content in your OP...rather than asking people to watch 15 minutes of tape that might be nothing but bullshit...

...you'd get better reaction.

You've watched the tape. Tell us what you've got to say. Otherwise sit here and talk to yourself. (Hope my comment gives your thread a boost.)

[cancel2 2022]

Maybe if you included some content in your OP...rather than asking people to watch 15 minutes of tape that might be nothing but bullshit...

...you'd get better reaction.

You've watched the tape. Tell us what you've got to say. Otherwise sit here and talk to yourself. (Hope my comment gives your thread a boost.)

Oh dear, so you have to watch a video ffs!

[floridafan]

Oh dear, so you have to watch a video ffs!

maybe you need to watch also, honey bunny, but it may be just a bit technical for you. Best you go back and make some cookies.

[Frank Apisa]

Oh dear, so you have to watch a video ffs!

No I do not, actually.

Haven't...and won't.

I seldom do when someone is so lazy they just post a video without a reasonable OP accompanying.

My guess is lots of people do that.

Why not stop being lazy...if you have a point you think is worth making?

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No I do not, actually.

Haven't...and won't.

I seldom do when someone is so lazy they just post a video without a reasonable OP accompanying.

My guess is lots of people do that.

Why not stop being lazy...if you have a point you think is worth making?

If you don't want to watch it, then up to you! I know about them already, you don't.

[cancel2 2022]

maybe you need to watch also, honey bunny, but it may be just a bit technical for you. Best you go back and make some cookies.

This from the fool that thought the video about palm oil was made in Iceland ffs!!

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If you don't want to watch it, then up to you! I know about them already, you don't.

I'll just say this, aerospike engines are far more efficient than rocket engines with conical nozzles. They were intended to be used to power single stage to orbit craft after the Space Shuttle, but are in a state of hiatus at present.

[FUCK THE POLICE]

Aerospikes are generalist engines. But staging usually makes more sense, you can use engines that are more efficient in space, and launcher engines that are more effective in atmospheric conditions. Aerospikes would mainly be useful for an SSTO, because they'd remain recently efficient at all altitudes. but an SSTO in general has been sort of the white whale of the space industry. Also it's kind of pointless now that we have reusable staged rockets.

[FUCK THE POLICE]

He kind of brushed over the x-33. The problem with SSTO's is that it's just marginally possible for them to fly themselves into space and carry any useful amount of cargo. It hurts a great deal to have to carry around a tank at all times. The X-33 tried to develop a novel new lightweight tank, but ultimately it still weighed so much that it couldn't carry any cargo into orbit, it would've only barely been able to lift itself into orbit empty and return. Clearly that is entirely useless. And that's what winds up happening with most SSTO's.

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Aerospikes are generalist engines. But staging usually makes more sense, you can use engines that are more efficient in space, and launcher engines that are more effective in atmospheric conditions. Aerospikes would mainly be useful for an SSTO, because they'd remain recently efficient at all altitudes. but an SSTO in general has been sort of the white whale of the space industry. Also it's kind of pointless now that we have reusable staged rockets.

There is nothing to stop multi-stage vehicles from using aerospike engines, at least for the first stage. In general a space vehicle fitted with an aerospike engine uses 25–30% less fuel at low altitudes. The Space Shuttle was going to use aerospike engines but was decided against reasons that are still clouded in mystery.

ARCA is carrying on the good work.

http://www.arcaspace.com/

[FUCK THE POLICE]

The first stage is the part of the rocket where efficiency actually matters *least* though, in terms of delta v (the total ability of the rocket to change its velocity). Like they intentionally use low isp, high thrust engines based on kerosene in the lower stage just to save on volume in most cases (which is much denser, but less efficient, than the hydrogen often used at higher stages). I can totally see why they wouldn't want to bother with an aerospike there, if it was just a little bit more unreliable or produced less thrust it likely wouldn't be worth it.

Whereas in the upper stage, efficiency increasingly becomes totally critical. Once in orbit you have all the time in the world to change your velocity, so you don't care as much about thrust. But every tiny little bit of extra fuel, requires many times that amount of fuel in the lower stages just to carry it into space.

The extreme version of this of course is the ion engine. Which provides about as much thrust as the force of a piece of paper falling on your hand, but has an isp like 10x anything you can get via chemical means. So it can send things very far out into space given enough time. Unfortunately if it were carrying humans the mass would be too much, it would take years and years to get anywhere and we simply can't wait that much time.

Aerospikes are definitely they are a cool technology though.

[Fentoine Lum]

This is a very fascinating subject, but apathy reigns as per usual on JPP.

You draw that out in people.

[FUCK THE POLICE]

Tbh mainly all I know about aerospikes is that when I designed rockets with them in Kerbal Space Program, and calculated the delta-v of the resulting vehicle, it never helped out. Almost always there were better alternatives. I did once design an SSTO, but I went for SABRE type engines for that (which are *much* more efficient than aerospikes *while there's enough oxygen in the air for them to combust*), as well as an airplane type liftoff. Maybe I'll try again with an aerospike design.