I'm not a professional, so I cannot evaluate any particular technical risk as you asked. However, I feel that NASA should mitigate the programmatic risk of a failure by being more forthright about the possibility of a failure. The current message as understood by the public is "Artemis I will succeed". It should be made more clear that Artemis I is a test and it might go boom. The public would accept that. In fact the public likes things that have a risk of going boom, like stock car races, as long as the risk is stated in advance.One specific example is the SRB pull date. NASA should be explicit here, and state that the SRBs are past due. They will almost certainly work, but NASA has chosen to accept the risk because it's cheaper to lose the mission (and thereby gain valuable information) than it would be to scrub the mission and de-stack. I think the public will accept this if it is publicized before the mission.
The long stack time of the SRBs is really the only glaring thing that seems to be an obvious potential problem right now, and I think that's attributable to NASA being willing to take more risks on an uncrewed test flight than they would with people on board.
Quote from: whitelancer64 on 05/03/2022 03:52 pmThe long stack time of the SRBs is really the only glaring thing that seems to be an obvious potential problem right now, and I think that's attributable to NASA being willing to take more risks on an uncrewed test flight than they would with people on board. My uninformed guess agrees with your professional opinion. Why don't they say so?
Vibrations, electronics, solder joints and trace continuity. The Orion program has a history with cracked traces in vibration testing. The SLS #4 engine controller that stopped working was attributed to a solder joint. If I were to guess why Artemis-1 might go badly wrong during ascent, it would be something like that. It's a particularly violent ride on the SRBs for untold millions of tiny electrical conductors.
Comparing Starship failure rates to SLS is like comparing two completely different systems. Starship may turn out to have the highest failure rate of any launch vehicle of all time. Chances Starship fails on the next flight are very very high. In fact, makes you wonder if Starship is just designed to fail - as if to say, if we couldnít make our stuff work, then the other stuff surely wouldnít work. Seen this play out as a marketing trick in the industry during the 90s.But SLS has tremendous heritage. It will be highly successful.
I would say 50-50 for the inaugural flight, including all possible "launch vehicle failures" during ascent, including orbit shortfalls, etc.
I think the most likely failure cause for Artemis I is flight software. It is brand new and as I understand it Boeing was responsible for its definition, creation, and verification. Several years ago the development of SLS core stage flight software was reportedly in disarray and behind schedule. Of course Boeing's failings with CST-100 software is well known. I think the odds of LOV is about 10% and LOM is about 20%.