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SpaceX Starship - IFT-3 - Starbase TX - Pre-Launch Preparations Thread
- Thread starter VIKING26
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Well that was unexpected. But what exactly will a “propellant transfer demonstration” include? There will only be one vehicle involved with IFT-3, obviously.
SpaceX is under a lot of pressure from NASA to make progress on the HLS. I hope they are not rushing this “demonstration”. They have yet to get Starship to orbit…
SpaceX is under a lot of pressure from NASA to make progress on the HLS. I hope they are not rushing this “demonstration”. They have yet to get Starship to orbit…
How about this? Move propellant from the main tanks to the header tanks.
The idea is that if you fire your engines in microgravity, you need to use the header tanks, which always start full. But if you do that, then turn the engines off again, you have partially-depleted header tanks and you can't relight your engines. So the demonstration could be a way of firing the engines using the header tanks, which seats the propellant in the main tanks, which allows you switch back to the main tanks. Then you stop using the header tanks, pump from the main tanks to the header tanks to top them off again, and you're ready for another microgravity engine restart.
If that is what will happen then SpaceX needs to actually get to orbit instead of "almost orbit?" Unless NASA will consider it a success in an almost orbit situation. One full orbit around the planet before the landing near Hawaii. The reality is that once you're there it isn't much more to get an extra orbit in.
Edit: Or how about this: The Starship does a propellant transfer with something already in orbit launched from a Falcon 9!
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60 minutes of orbiting is long enough to show the transfer works. Risky to rely on a deorbit burn.
Interestingly, in this Ars article, "Don’t count on NASA to return humans to the Moon in 2025 or 2026, GAO says", it does say that SpaceX's delays with Starship, and Axiom's delays with the suits, may cause schedule slip for the moon mission, so there is some pressure.
That having been said, I suspect SpaceX would have done this regardless. If, based on data from your last flight, you have reason to believe you've identified and corrected issues that will allow you to reach your next milestone, why not do something while there?
Kind of like hot staging... they decided to test that with IFT-2 when they couldn't even keep all the booster engines lit on IFT-1. But they knew they had fixed things, and would likely get to stage separation, so they went for it. And they got opportunity to test and validate a lot more stuff.
They seem to work under the idea that every test flight should end up with something that has maybe only a 50/50 chance of working...each flight practically guarantees they'll learn from a failure. And they make extremely rapid progress as a result.
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While the booster and Starship are guaranteed losses, they should definitely be trying out the stuff that is most risky to the vehicles. Once they have vehicle landing worked out, they're going to need to have all the risky stuff locked down.
Internal, of course
As part of the NASA Tipping Point Award outlined in this Spaceflight Now article: NASA selects proposals to demonstrate in-space refueling and propellant depot tech
Thanks, that seems pretty clear that the propellant transfer test will be intra-vehicle.
But what would be learned from a test like that? The objective is a transfer between two Starships that are docked together. Would such a test be about the pump system’s operation in microgravity?
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Thrust and/ or pump based transfer testing for feasibility and performance. The docking system is a thing, but from a fluids point of view, it's 'just' more plumbing.
Booster 10 has received a hot staging ring. It looks to be the same design as the last one.
I never checked the mass of LOX in the header tank. It's about 21 tons when full, so they could definitely play with the header tank and hit the 10 ton test goal. For the curious, there's a bit under 7 tons in a full CH4 header tank.
Edit: Bonus content. Worth a read. It goes into other propellant-related projects as well as the fact that the data from these tests will not be made public.
arstechnica.com
Edit: Bonus content. Worth a read. It goes into other propellant-related projects as well as the fact that the data from these tests will not be made public.
NASA says SpaceX’s next Starship flight could test refueling tech
SpaceX appears on track for at least a preliminary propellant transfer test next year.
arstechnica.com
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I kinda feel like the design points most likely to be changed for the HSR's would be (in descending order of likelihood):
1- The heatshield dome (subject to most extreme conditions & hard to test on the ground, hence none known)
2- The vent "slots" (also hard to test, but maybe easier to model?, probably subject to less intense conditions)
3- Structural compression strength (ground tested with can crusher)
I'll be interested to see if we can determine they made any changes to the dome that we can't see yet...
I just want to see the video. Surely they had cameras inside the base of the Starship engine bay to record what happened at hot staging. Maybe there was nothing to see, given all the gasses being thrown around.
In truth, it would be nice if they released any onboard footage.
Yes..
It's rather interesting that at this point we haven't seen any on-board video. Or Elon hasn't tweeted about what failed.
Not that SpaceX is obligated to share any of that, but they've never hesitated to do that in the past (unless contractually obligated not too).
Maybe they don't know at this point, but I'd be surprised if so... they have to have instrumented the snot out of Starship.
I kinda expected a tweet form Elon a week ago saying something...
He may have been preoccupied with the Cybertruck delivery event since the launch. I hear that he has a rather busy life. Or the SpaceX folks are looking over all that wonderful data to understand it themselves. It's only been two and a half weeks.
I wish that Elon would focus his addiction for attention on the people who appreciate his statements. He makes social commentary and gets crucified by haters, but if he talks technical, he gets adored by fans. Perhaps his upbringing just pushes him to stoke the haters. If he'd just let us know, I'm sure we could get some technical folks to call him stupid on a regular basis.
Yeah maybe, although it's gonna be the SpaceX folks poring over the telemetry... I'm sure once the root cause is ID'd he could find 30 seconds to Xpress while sitting on the pot...
I suspect that Elon being "on the spectrum" plays into this. Engineering and technical folks tend to not be terribly emotional/excitable, and that stuff is simply much more objective... math don't lie. People, however, do. And in social/political/business areas, there's tons more subjectivity, even with people acting in "good faith". Then there's Elon's opponents who aren't afraid to use those avenues to cast whatever negative light they can on him & his endeavors.
Whereas many folks will hold back in expressing themselves fully in what they think/believe to be true in some situations, in order to avoid giving their enemies ammunition, I think Elon has a hard time with that. He wants to state things as he truly sees them, h8ters be damned. And he seems willing to take the heat for it... but it's cost him more than once.
I personally find it refreshing, I'd much rather have a straight (but unpolished) shooter, than some slick CEO salesdroid. But I know many people who don't seem to be able to take it in context, and they get worked up.
(Definitely taking this thread off track. We can probably find a better home for this if we want to discuss further)
Not sure if this is the right place, but it is specific to preparations for IFT-3; sling adapters have been installed on B10 (the booster planned to be used for this launch) and the chopsticks were tested, both actions presumably getting ready for placing B10 on the OLM for its first static fire.
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