FWIW, it should be remembered that SpaceX's Raptor is currently blueprints at most, and would be manufactured by a company with no prior hydrolox experience. Naturally, no non-US engine would even be considered for a 'flagship' like SLS.So, I'm afraid something PWR or Aerojet is pretty much the only game in town right now.
The goal is to design the core only once, qualify it and fly it until SLS itself is replaced 40 years from now. Follow the Soyuz model; build it once - fly it forever. Let all subsequent development be in the upper stage(s).
Quote from: Ben the Space Brit on 10/20/2010 12:16 pmFWIW, it should be remembered that SpaceX's Raptor is currently blueprints at most, and would be manufactured by a company with no prior hydrolox experience. Naturally, no non-US engine would even be considered for a 'flagship' like SLS.So, I'm afraid something PWR or Aerojet is pretty much the only game in town right now.They didn't have any RP-1 experience before 2002. If this upper stage is anything like 8 years away, like if we fly the HLV without an US for LEO work initially, Raptor may be right there waiting.