Starship Super Heavy booster came within one second of aborting first “catch” landing
ptfrd @ ptfrd @sh.itjust.works Posts 5Comments 99Joined 1 yr. ago
ptfrd @ ptfrd @sh.itjust.works
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Interesting! They're talking about unnecessary aborts, and how they want to do as much analysis as possible of the abort criteria, to prevent them.
This will remain an issue for Flight 6 which, it seems, will happen the moment SpaceX decides it's sufficiently ready. Unlike previous flights ...
"Given this is the first launch in a long time ... well really ever ... that we've not been FAA driven ..."
This would be a nuclear option and, in reality, probably would do more harm than good to SpaceX,
It would probably set back their more ambitious targets by decades. But even Starship is now far enough along to no longer really need Musk's stewardship, and the US government would be happy enough just with control of the Falcon programme. They don't care much / at all about Making Life Multi-Planetary.
So I consider a move like this pretty plausible.
If so, why would SpaceX have so rapidly & aggressively moved to restore Ukraine's communications capabilities in the early days and weeks of the current war, and maintained them ever since?
One of my favourite videos of the catch, because of what happens when the sonic booms arrive!: https://youtu.be/749dRxbSkVU (They're at 6:51.) Also it's a different angle from most of the others, because it's from Mexico.
And a playlist: Starship IFT5 booster catch, original footage only
You heard it on Lemmy first!: https://sh.itjust.works/post/25840892 (very soon after Stich first mentioned it)
Link currently doesn't WFM.
I believe when you create a clip from an ongoing YouTube live stream, it will (at best) only work as long as the footage you selected is still available on the stream. And I believe YouTube only keeps the most recent 12 hours of footage.
(What they should do is create a permanent copy of the relevant footage, assuming the channel owner permits it.)
The fairing looks spotless. I guess they're using a new one, at least partly for reasons of cleanliness? (Planetary protection and all that.)
With boosters we're at the point where "flight proven" is no longer just a euphemism for "second hand". I've felt that way myself for a few years. And NASA basically confirmed they agree a couple of months ago, when the brand new booster intended for Crew-9 was given a Starlink mission first, increasing confidence in it after a minor problem during transport. (IIRC)
But I'm not sure if we're at that point with fairings. Or even if we'll ever be.
I like SpaceX's Sarah Walker, despite (or partly because of?) the fact that she tends not to answer questions from mere mortals (non-SpaceX / non-NASA personnel).
For example, at the Post-Launch News Conference, there was a question about pulsive splashdown (although that term was not used).
She seemed to imply that the capability would have been available for Crew-7 if it wasn't for a problem with one of the GPS sensors. (Was this problem known about well in advance of undocking? Would that be why they didn't announce the new capability at the time?)
She spent most of the time confirming the point I made in my first comment on this post, about taking into account any extra risks that this capability might add, and she said that it had taken "years".
She didn't answer whether it's available if the parachutes fail during a launch abort, nor tell us any of the (non-NASA) missions it has been active for (of which Gerst had said there were "several").
Here's the question: https://www.youtube.com/live/wwhfph1vGdE?t=32m30s (at 32:30)
When composing the title of this post I nearly called this technique 'Propulsive Splashdown', but I didn't remember ever hearing that term used before. (Stitch didn't call it that, did he?)
Later I heard Stephen Clark use that term in his question. And yesterday that term was used during the launch stream. Nail and Cardman spent a minute discussing the capability: https://www.youtube.com/live/SKXtysRx0b4?t=3h29m8s (from 3:29:08)
Apparently they often abbreviate it to "prop splash".
Animation of a 'land landing': https://youtu.be/Cf_-g3UWQ04?t=1m32s
Not really. There's a hover test vid uploaded in 2016 but they cheated. (It's held up by a rope!)
Or you could play the first 17 seconds of the pad abort test in reverse ...
At 52:05, Stephen Clark asked about this. The start of Gerst's answer is:
We've actually flown it on several other dragon flights before this. This is the first time it flies on a NASA mission.
So, perhaps Inspiration 4? Presumably Polaris Dawn? And I guess the Axiom missions are being counted as non-NASA in this context, so some of those?
Before doing something like this I think you should ensure that it reduces the overall risk to the crew. So you'd need to have an estimate of how likely it is that all the parachutes fail, and how likely it is that the SuperDracos could save lives in that situation, but also an estimate of how likely this capability is to go wrong. For example, could there be a bug in the software or in some sensor(s), that causes the SuperDracos to fire when they weren't needed? Would the SuperDracos otherwise be in an inactive state during re-entry, and if so, what are the risks of having them active? Etc..
Those 2 sentences from Gerstenmaier suggest to me that SpaceX had already decided that, on balance, this capability should be enabled. Whereas NASA have only just reached that conclusion.
as far as I’m aware, they’ve done 1 EVA to look at the thing
Don't think so.
They do have access to camera imagery, but as you say, most problems like this probably need much more intrusive investigation.
A landing leg failure, for example, likely could be quickly cleared because it is not used in other phases of flight
I assume SpaceX wouldn't make any big assumptions along these lines though?
I imagine, for example, that a worn component that could fail catastrophically on landing might also be at risk of some kind of failure during max Q, in a way that affects the primary mission.
Of course, there could come a point where you judge that so unlikely as to be not worth wasting any (further) time on.
But as an armchair observer I'm fairly glad to see a pause at this point before Polaris Dawn, even just a couple of days ...
“We’re just focused on recovery weather at this point,” he said after the announcement of the FAA investigation into the booster landing anomaly. “I think that is still gate to our launch.”
Surprising. Does this mean they have good reason to think they'll get a Public Safety Determination in a matter of days? Does the FAA work weekends?
P.S. If a landing leg realistically could, say, pop open at max Q, I guess that further strengthens the argument in favour of rocket 'catchings' rather than rocket landings!
the host says they’re going to higher altitudes than the Apollo program
Ah, yes, well normally that would be my opportunity to remind people of Gell-Mann amnesia.
But this time it’s unfair to the host. Isaacman has made that mistake himself on (I think) multiple occasions. She might have got it from him. (Perhaps indirectly.) Here’s one: https://youtu.be/aASZ2rKdS6I?t=1m2s (He meant “since”, not “than”.)
One source of confusion might be if this crew is planning to be in the highest 'free' orbit of Earth ever occupied by humans. Where I'm using 'free' as a vague way of trying to exclude, for example, the astronauts who were actually on the moon (which is of course orbiting the Earth).
Is that a scientifically/technically legitimate & meaningful distinction? If so, is there a better term for it?
the host says they’re going to higher altitudes than the Apollo program
Ah, yes, well normally that would be my opportunity to remind people of Gell-Mann amnesia.
But this time it's unfair to the host. Isaacman has made that mistake himself on (I think) multiple occasions. She might have got it from him. (Perhaps indirectly.) Here's one: https://youtu.be/aASZ2rKdS6I?t=1m2s (He meant "since", not "than".)
this one doesn’t really have anything that makes it fundamentally unsafe.
You're probably right, but we'll see. The altitude and the spacewalk are the first big new initiatives for SpaceX's human spaceflight work that haven't been done under close NASA supervision. That's probably a good thing but ... I'm nervous.
Talking of the altitude, this is from the article:
The mission is scheduled to launch between 3:30 and 7 a.m. Eastern Aug. 26 in one of three instantaneous launch windows. Isaacman said the launch times were selected by SpaceX to minimize the micrometeoroid and orbital debris impact risk to the mission given its unconventional orbit.
He said it during the event (which is available to watch here), and I don't think any further explanation was given for why certain launch times are better than others for MMOD. Does anyone understand why? Is it obvious? Any resources I could check out to learn more?
Talking of the article, they still haven't fixed the first sentence!:
spacewalk on a is ready
If Jeff or anyone else from Space News is reading this, hire me as your proofreader!
Interesting title on the video about this, just uploaded to YT by CBS News: SpaceX sending private citizens on risky mission that includes spacewalk attempt
I find myself agreeing with the sentiment. I'm fairly nervous about this mission.
Don't get me wrong, I'd jump at the chance to join it. I'd choose it over a routine trip on Starliner, but not for the reason you might be thinking. ... I can't help wondering if Polaris Dawn is both higher risk and reward than a routine trip on Starliner.
No, that's this one, funded by a crypto billionaire, announced a week ago and launching in ~4 months.
Polaris Dawn is funded by a payments processing billionaire, announced 2.5 years ago, and launching this month.
That has to be a requirement regardless I guess since a depressurization could happen on any flight.
Yes, this has been pointed out by the crew (IIRC) in an interview about the mission. (Not to suggest that no work was needed on the issue, just less work than people might expect. Obviously it can be the case that taking an unlikely contingency scenario and making it a deliberate part of a mission, raises the level of assurance needed.)
For the "ship envelope expansion", do you think they will/should do an in-space engine relight test? Or are the seemingly successful flip-landing maneuvers on flights 4 and 5 sufficient? (Has this been covered elsewhere?)