/sci/ - Science & Math

>>11763404
They add too much complexity for too little gain in efficiency. Could work as both engines and heat shields though.

>>11763404
Everyday numale Astronaut did a full documentary on it. The consensus is modern rocket engines are quite high in efficiency and gains from Aerospikes isn't worth the R/D work needed to build a SSTO engine.

>>11763410
What do you mean it can work as a heat shield?

>>11763465
Not him, but they way I understand it, their operational temperatures and maybe the shape make them plausible to be used as heat shields during reentry. You would orientate the spacecraft retrograde and the engine would substitute a traditional thermal or ablative heat shield.

>>11763481
Ah I see thanks

>>11763404
Wouldn't work in space. For the same reason rockets don't work in space.

>>11763404
bell shaped are optimized for a certain air pressure, one that works well on the ground does not work as good in space, you need to use rocket stages, aerospikes can adjust and you could build better single stage spaceships

>>11763404
RDE is the new sexy.
Get this hag out of here.

>>11763404
They would be better than bell nozzles if they had the same amount of R&D but it will never happen

>>11763404
They're a good jack-of-all-trades engine. But they're not really "great" at any specific altitude. They're just okay. As such they are good for SSTOs, but remember that SSTOs are horribly impractical.

>Delta Clipper was a vertical landing/takeoff SSTO
>Mass of 36 Metric tons when dry, held 434 tons of propellant
>Only put FOUR tons of payload into LEO alone!

However

>Stack a Delta Clipper onto a stage with the exact same propellant mass/dry mass
>Put landing legs on the first stage, make it able to land as well
>100% reusable vehicle
>Can put 20 tons into LEO!

SSTOs are cool but they are impractical given that Two-Stage-Reusable vehicles can just put a payload several times larger into orbit, while only increasing the vehicle size by a factor of at most two or three.

As such, there's no need for an aerospace engine, as you do not have to optimize your impulse for all altitudes. You can just put a vacuum engine on the second stage, and a sea level one on the first.

Technical challenges aside, aerospikes just are impractical.

>>11764146
Maybe they could be useful for single stage to martian orbit transportation.

>>11764147
Maybe but if you want "practical" SSTO on mars you might as well just go nuclear.

Robert Zubrin had a design for a Mars-Specific SSTO called NIMF which used Carbon Monoxide and a nuclear reactor which allowed the vehicle to hop around and orbit mars without even needing ISRU. Plus mars is already an irridated hellhole.

>>11764146
Wouldn't SSTOs be good for human transportation to orbit? Seems better than a rocket launch every time.

>>11763465
Project ROMBUS would have used a circular aerospike with transpirational cooling because it would also be part of the main tankage. This aerospike would naturally function as a heatshield for reentry operations.