The Atlas is a system, not a particular launcher. From the 401 to the triple core Heavy, it is all the same system.....The human-rating is already happening to Atlas. It's not setting in place a human flight LV, it is using one that is already set in place and being developed for CCDev regardless,...
Already knew this part.
The Heavy version needs to be qualified, but the design work was done as part of the Atlas V program already....while qualifying the Heavy version already developed (to PDR last time I checked).
Being a teacher (Bio., Chem., Physics, and now elem.) who's passionate about space, but not a rocket scientist, I understand a good deal of the info. in these threads, but not the highly specialized engineering. If I am following you correctly, once the single core Atlas V is man rated, it is not that much more difficult to rate the CCB Heavy. With AV already being man rated for commercial crew, the 552 could carry the lighter Orion to LEO/EOR, and then it would not be too much more difficult to man rate the Heavy for the heavier Orion. It would be necessary to qualify a configuration of AV that has never been built. I am guessing that the pad situation may be more of an issue than qualifying the Heavy for manned flight. Am I following correctly and drawing the right conclusions?
You got it, although the 552 can carry the full Orion, but with reduced capability due to the use of the SM engine for final orbital burn. (good way to do a full test however) You can also carry the full Orion, without a crew (hence no LAS) without use of the SM for orbital burn. Handy for a reboost/crew rescue mission to the ISS.
This begs a bit of an interesting question.
Assuming NASA wanted to send Orion to ISS for a crew rotation, because of some delay/issue with Commercial Crew. But they don’t really want to use full SLS. Let’s say it’s 2018, Orion’s checked out and ready, and AV is man-rated and ready for Commercial crew to be ready.
Are there any options for sending Orion to ISS on single stick AV? (with SRB’s if they will be man-rated as part of the program. That I didn’t know).
Meaning, could Orion be sent up without the SM, but with some trunk instead with the ECLSS system? Does the capsule have enough battery power to get to the ISS and dock?
(thus would be running off ISS power I assume while docked?)
Can Centaur get the Orion Capsule by itself to the ISS? I think the capsule is around 8mt by itself? Maybe with a little heatshield protecting trunk? Then Orion uses it’s RCS to depart the ISS and do reentry? Not sure how heavy the LAS is, but the whole Orion/SM/LAS stack masses around 22mt, right? SO if the SM is removed, and just a light trunk installed, that should reduce the mass down to where an AV-551 or something could get Orion with a crew to the ISS, I’d think.
Or, as a different option, could Full Orion be sent on an AV, and have the SMME do the 2nd stage and circ burn? Dunno if it could, just curious if it could if it was only pushing the CM to orbit. So AV wouldn’t be pushing the weight of Centaur, and the SM acted as the 2nd stage, maybe it could get Orion to the ISS? When would the LAS be jettisoned compared to when the core would separate? I think the SM having to push the LAS would be an additional problem.
I’d think the first option would be more likely due to the better isp and fuel capacity of Centaur vs. the Service Module. But I don’t know. This just got me thinking about some options. Basically, if just going to the ISS, the capsule doesn’t need much. I don’t think CST-100 even has solar panels in the trunk, or much else other than the pusher LAS. And thus has to get to the ISS shortly after launch. Could something like that be done with Orion, in a pinch?