Common Extensible Cryogenic Engine

The reason water ice is generated at the nozzle exit is due to three factors: First, the major combustion byproduct of LOX and LH2 is water, H20. Secondly, The large area ratio of the nozzle, which is optimized for vacuum conditions, actually results in drastic cooling of the exhaust gases. Finally, the use of propellant for nozzle cooling results in a exceptionally cold nozzle wall, where ice can form.

awesome blue streak!!!

Seems kind of silly to use this engine for a lunar landing. For anything going to or from the lunar surface you want absolute reliability which is something that H2/LOX engines do not provide. In Apollo they used a hyperglycolic engine and right for doing so because the fuels react on contact. Imagine how horrible it would have been if Neil and Buzz were stranded on the moon because they used a cryo engine that failed to ignite. It would have killed the space program.

Safest underground in the bunker...

H ** 2 and O ** 2 give the maximum specific impulse at minimum weight among chemical rockets.

That can be justified by reliability and safety analysis. But double the critical function s will increase the weight...

The hypergollic OME from the shuttle is probably a better choice as far as reliability followed by the pressure fed Kero LOX Kestrel off Falcon 1.
Though the hydrogen engine is in the LSAM for two reasons one Ares I can't do it's job so LOI is moved to Altair and they think someday they could refuel the lander via ISRU.
Though by the time you got ISRU on the level to refuel a spacecraft you would not be flying Altair or Orion any more as both vehicles would have long since been retired.

Thanks for explaining this! I saw this video and I always wondered "How the heck is this engine creating ice? Isn't the exhaust thousands of degrees?"

Excellent work NASA. Glad to hear they've created a more powerful engine with lighter fuel.

They didn't "create" a new engine. It's just a RL-10 with deep throttle capabilities below 10% of it's rated thrust as needed for the new lunar lander.

Yes, that was a bad word for me to use. I already know about this engine, what I meant to say is that it's good they've created a new variation of this engine that is useful for landing.

yeah, I have one of those in my shed, I don't use it a lot though. But so once in a while I take it out for a spin.