Bridenstine Reiterates December Launch to ISS on Track, and Other Space Council Tidbits Space Policy Online
Bridenstine: “‘We have a really, really good idea of what the issue is’ and there will be a ‘number of Soyuz launches in the next month and a half’ before a launch with a crew. He called it the ‘most successful failed launch we could have imagined.‘”
Marc’s note: Are the Russians about to pull a rabbit out of their hat and make a human return to flight in December? Between now and then there will be two Soyuz launches, one cargo resupply to the space station and the other a satellite.
Will Russia Launch Astronauts to the ISS in December?
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If they can’t quite meet the December deadline I wonder if they will try and get a waiver to the on-orbit limit for the capsule that is currently at the station, especially if they just need a few more weeks. The preference is that the outgoing crew is still on station for a week or so after the new crew arrives. Even with all of their training, I think it would be difficult for a new crew to arrive to an empty station and have to immediately jump into all of the activities without the previous crew there to help them.
Maybe an extension isn’t possible, but it could also be that they aren’t going to even float the idea unless it starts to look like they might not be able to get the new crew up there in December.
The time limit is due to decomposition of the hydrogen peroxide monopropellant which is used in the descent module’s reaction control system. I’m not sure you can grant a waiver for a chemical reaction that’s out of your control.
Actually, a waiver doesn’t strike me as unrealistic. The decomposition is temperature-dependent. I know it also depends on UV exposure (which should be a nonissue in an opaque tank) so it’s probably also affected by radiation (e.g. X rays from bremsstrahlung.) Oh, and impurities can catalyze decomposition. Who knows what else? Also estimating the amount of propellent in a spacecraft’s tanks is harder than most people realize.
All that means there is uncertainty in how much usable hydrogen peroxide is still in the tanks after 200 days in orbit. The normal way of dealing with that sort of uncertainty is to add margin. I’m fairly sure that’s the Russian approach as well. And how much margin you need is a judgement call, not a chemical rate constant. If a 200 day limit is based on 99% confidence that enough propellent will remain, someone could waive the 99% requirement, say 98% is good enough, and allow more time in orbit.
Marc asks “Will Russia Launch Astronauts to the ISS in December?”
Michael asks: “Would YOU strap that sucker on for a ride in December?”
Was the launch last night a Soyuz? Sounds like it was successful.
It was a Soyuz 2 (not to be confused with the Soyuz 2 mission in 1968… I really wish the Russians would stop overloading names.) That’s the next generation version of the Soyuz launch vehicle. Whether or not that qualifies as a successful Soyuz flight isn’t clear. It depends on what caused the previous failure and how similar Soyuz and Soyuz 2 are in that respect. (Or, as more cautious people in the field might feel, it doesn’t because the two are different. Period, end of sentence. Even if the relevant components are similar, the launch loads and stresses wouldn’t be.)
I think I was one of the people who complained about NASA grounding an entire type of launch vehicle while investigating a failure (as opposed to the FAA approach to aircraft operations.) So I guess I can’t complain about the Russians putting Soyuz back in service by December. But I can wonder if NASA’s risk posture is consistent.
What if, at some point, there were a Falcon 9/Dragon 2 launch failure, with the crew surviving an in-flight abort? Would NASA be satisfied with three months to investigate and fix the problem, in parallel with three unmanned flights (including flights which did not include the fix?) Or would they want an investigation which lasted as long as necessary, fixes for any other concerns the investigation board had, and six unmanned, post-fix unmanned flights? I’m not debating what NASA’s risk posture should be (at least not here and now), I’m wondering if NASA is uniformly applying that to all crew vehicles in a consistent manner.
IMHO they’re not applying any consistency to crewed launch vehicles. How many flights of Atlas V will we see with the re-introduced dual engine Centaur before it flies a crew on board? And how many flights of SLS are required before crew flies on it? Compare both of those to how many flights they want to see of Falcon 9 Block 5 with the new COPV tanks (even though there hasn’t been a single failure of the old COPV since SpaceX tweaked the helium and LOX loading procedures).
When it comes to Russia, NASA likes to portray itself like it has proper oversight and influence over the Soyuz launch vehicle. They don’t. So they’ll take whatever Russia says they’re going to do and spin it so it sounds positive.
My guess is that even after commercial crew is flying, we’ll still see US astronauts fly on Soyuz as well as Russians flying on commercial crew. This is despite the fact that Russian launch vehicles and crewed Soyuz appear to be declining in reliability and NASA has little to no influence on that decline.
The data for the Soyuz 2 launch vehicle is dismal (about 8% failure rate), and that’s the newest, most sophisticated, version of Soyuz that Russia has.
Why should there be consistency in assessing these vehicles?
Sure, the pointy end is up, and the fiery end is down, but that’s about where the similarity ends. Take for instance the issue of when to fuel the vehicle. Or where to place O2 or H2 or kerosene tanks WRT each other. Type of fuel(s). Type of oxidizer(s). Presence or absence of solids. Method of insuring that the stack is structurally sound. Etc.
There’s also track record. And even with little history when an issue is clearly the cause of a problem, resolving that particular issue means return to flight (SX managed to bump the second stage with the first, for instance).
[DISCLAIMER: I am not a rocket scientist. Just an interested citizen who can easily point out major differences in these launch systems. OTOH I could be full of sh*t.]
The different rockets are certainly different. But I think the rules for acceptable risk and recovery from a launch failure should be the same. At least at a relatively high level. For example, does changing the design require recertification? I think that should be the same for Soyuz and Falcon 9. What recertification involves might be different, but that’s a lower level requirement.
Try this analogy. To register a car, it has to pass an inspection and that inspection included demonstrating that its emissions are below some limit. All cars have to do that (I think.) But if it’s an electric car, no test is necessary. So this is a trivially easy requirement to satisfy. But the requirement is still there. (And, in the case of an electric car made by VW, we might still want a test.)
The difficulty is that a certification process, at least for the US, tends to be a) lengthy and b) administrative in nature, so while it may provide a sense of assurance for management it is not clear that it affects reliability and it may actually delay the introduction of design changes which will enhance reliabillity. The improved O-ring design for the Shuutle SRB is a case in point; leakage was apparent fromt he early flights and a design change was in the works but had not been certified at the time of the Challanger loss. On the other hand, at least one and preferably several unmanned launches when a design change is made do provide at least a preliminary bound on reliability/
The Soyuz-2.x failures have been all third stage/payload interface issues, as far as I can see. No issues with the first/second stage, and no issues with the new first/second stage flight control system, which is the major difference from Soyuz-U/FG as I understand it. So the first/second stage performance seems solid at least (74 from 74 for Soyuz-2.x, on top of 64 from 65 for Soyuz-FG) so “dismal” is a bit harsh, although applicable to third stage performance.
FWIW, in the event of improper stage separation, I think it is unlikely that the Soyuz-2.x would have performed any better than the Soyuz-FG. It’s not clear yet from the available information whether the improper stage separation would be more or less likely to occur in the first place with the Soyuz-2.x.
The first Soyuz-MS launch on a Soyuz-2.1a is not due until Sept 2019. Not sure what’s driving that timeline – using Soyuz-FG stock?
Of course the Russians will launch, they are risk takers and will gamble on it being successful. Since the failure was probably a manufacturing defect of one of the components the odds are in their favor it will be successful. The real question is if NASA wants to risk an astronaut on it.
Based on what the Administrator said, it looks like NASA will risk an astronaut on that flight. I think the real question is why NASA is willing to accept that level of risk on a Russian launch, but (apparently) not on an American launch.
Yes, they seem to have a double standard.
This has been true for many years, i.e. the lack of immediate ground egress which is required for US launches. The unspoken rationale has been the relaively long track record of the Soyuz but of course a reliable design does not protect against a deficit in quality control.
Iâm more concerned about the reliability, safety, and cost of commercial crew. That being said we should have tested out an unmanned ISS and unmanned Soyuz launch and return long ago. Should have also let china in on ISS. ISS needs to be the worldâs space station.