I try to follow news about space everyday, especially about the SLS/Orion development, but it seems I cannot follow it unless I am a member of the SLS team!
I was reading about the progress on the upper stage of the SLS and it was mentioned that it is using the J-2X motor. I thought they changed over to using four RL-10 engines? I see other websites also showing either the J-2X or the RL-10. Are they using the J-2X for the first launch of the 70 ton version and using the RL-10 for the 130 ton version?
SM
