BFR Developments

[Yazata]

Moving and poignant Starship short film by Christian Debney. Very well done.

https://www.youtube-nocookie.com/embed/Ywggi3-u4SA

[Yazata]

SpaceX has announced that they are recycling towards a second try on Thursday April 20, with a window that opens at 8:28AM CDT and closes 9:30AM that morning.

https://twitter.com/SpaceX/status/1648092752893313024

https://www.spacex.com/launches/mission/...light-test

[Yazata]

Here's where Thursday's SpaceX livestream will be.

https://www.youtube-nocookie.com/embed/-1wcilQ58hI

[Yazata]

Photo by Melissa Cavanaugh of Elon at the top of the High Bay at Starbase

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And after a day of frantic work, by more workers than anyone has ever seen on the OLM at any one time, they seem to have fixed whatever caused the scrub on Monday. It appears to have been something to do with the TVC (thrust vector control) hydraulics and the HPU (hydraulic power unit).

The workers know about the live-stream cameras and after they were finished, some of them assembled atop the BQD (booster quick disconnect) to wave at the cameras!

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And here's a couple of workers making a heart with their arms!

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The workers love what they are doing and they love their fans!

[Yazata]

They are already purging the booster and ship tanks with gaseous nitrogen. The build site is being evacuated as I write this.

And the photographers are ready. In Texas, cameras sprout from the soil like weeds.

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[Yazata]

Roughly T - 3 hours - the tank farm is coming alive, preparing to prechill the lines from the tank farm to the pad, so that cryofluids don't boil trying to flow through them.

Roughly T - 1 hour, 50 minutes - go for propellant load - the WB 57 is taking off from Houston

Roughly T - 1 hour - the WB 57 is on station

T - 33 minutes - countdown proceeding

T - 12 minutes - no significant issues

T - 7 minutes - closing out loading of all 10 million pounds of propellant

Launch looked good, it cleared the tower and passed through max-q, but appeared to have lost several engines. Then it appeared to be having trouble with pitch and yaw control, stack started to tumble and FTS may have been activated at that point. Vehicle broke up.

https://twitter.com/elonmusk/status/1649052609590992901

Back at the launch site, lots of debris thrown around. First photos of the OLM show what appears to be significant damage, including what might be a crater underneath it.

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Full SpaceX video from launch to flight termination - shows booster losing control late in its ascent

https://twitter.com/CollinRugg/status/16...3747011584

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Photo from SpaceX stream showing as many as six engines out.

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[C C]

[...] Back at the launch site, lots of debris thrown around. First photos of the OLM show what appears to be significant damage, including what might be a crater underneath it.

https://pbs.twimg.com/media/FuKl3PcWwAIj...name=small

Not wholly surprised. It seemed to take so long to lift off the pad that I started to wonder if it was going to blow up then and there. What was underneath probably received some prolonged abuse.

[Yazata]

Video of nasaspaceflight.com's live-stream camera car getting obliterated yesterday.

It's the white car on the right in the camera-garden photo in a post above. The video was taken by LabPadre's live-stream camera car, the dark SUV to the left in that photo. (Lab's car and its gear survived with minor damage.)

This is why there was the extensive keep-out zone around the launch. SpaceX allowed photographers to put remotely-operated cameras in selected places in the zone, but the photographers had to sign waivers saying they were putting their gear in there of their own volition and absolving SpaceX of any damages.

https://twitter.com/JerryPikePhoto/statu...2698784771

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[...] Back at the launch site, lots of debris thrown around. First photos of the OLM show what appears to be significant damage, including what might be a crater underneath it.

https://pbs.twimg.com/media/FuKl3PcWwAIj...name=small

Not wholly surprised. It seemed to take so long to lift off the pad that I started to wonder if it was going to blow up then and there. What was underneath probably received some prolonged abuse.

Yeah CC, I was thinking that too.

Starship is said to have a rather hefty 1.5/1 thrust to weight ratio, which should get it off the pad very quickly. (Like those solid-fueled repurposed-ICBMs that just leap off the pad into the sky.)

But if they had it throttled back to 90% which I believe it was, that would be 1.35/1, which still isn't bad.

And... if those six dead raptors in the photo weren't operating at the beginning, that would be 1.11/1. It would still rise off the pad, but much more slowly. As you say, that would have subjected the pad to abuse for longer than expected.

On the plus side, I suspect that when it lifted off, as few as 3 engines were out, which at 90% throttle would have given them 1.23 to 1.

On the minus side, if all 3 of the failed engines were on one side, the flight computer very likely throttled engines down on the opposite side to balance the thrust. That would have effectively increased the loss of thrust back to 6 engines worth and 1.11/1.

Edit - I should add that I'm increasingly skeptical of that photo of the crater under the launch mount I posted above. I'm starting to suspect it's a fake.

[Yazata]

Twitter is alive with theories and speculations. (That's one reason why I love it.)

Of particular interest are some photos that are said to have been circulated inside SpaceX to employees, then leaked.

This one seems to show Ship 24 with the top dome section of Booster 7 still attached to it. What may or may not be the rest of the booster might be visible in the distance in the lower right.

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A theory that is said to have accompanied this photo (supposedly) from inside SpaceX says that pad debris from the launch disabled the hydraulic power units (HPUs). This froze the hydraulic actuated clamps that hold the stages together, so they couldn't separate. The observed booster tumbling was thus said to be the booster trying to do its boostback flip, with the second stage still attached.

Some outside observers (including me) don't think that theory is entirely plausible. The tumbling appears to have begun some time (as much as 20 seconds) before main engine cutoff (MECO), the booster engines were still running when it happened, and it seems to have been proceeded by erratic flight by the booster.

My theory is that the HPUs were indeed damaged at takeoff. (Or before, they were having trouble with them which scrubbed Monday's flight.) A hydraulic leak gradually took out the booster's thrust vector control (TVC) that wiggles the engines to steer. Unable to steer properly, the booster lost pitch/yaw control which accounts for its increasingly erratic flight and eventual tumbling. The clamps holding the stages together may have been jammed by that. Unclear if the booster's flight termination system was activated at that time, which would account for the booster breaking up. The ship's FTS was activated subsequently.

Of course I don't know and most of those on Twitter don't know. But that doesn't prevent us from speculating.

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This is kind of cool. Mexican space nuts gathered at the southern mouth of the Rio Grande, to watch Starship launch. This is probably the closest place people were allowed to get, since the SpaceX exclusion zone was only on the US side.

https://twitter.com/FronteraSpacial/stat...2531131392

Their video really captures the incredible rocket launch noise. There's an interesting bright flash on the way up that they exclaim about. It might have been another engine failing or perhaps the poor suffering HPU, spraying hydraulic fluid into the exhaust plume.

Another video from the Mexican side

https://twitter.com/TechSpatiales/status...0457118722

[Yazata]

From the Daily Hopper

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