rocket landing off of Hawaii

[leilanidude]

"... rocket was supposed to flip 180, separate, then the booster would go do "it's thing" for touchdown..."
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I don't think flipping 180 to point straight back down, was what it was supposed to do? Maybe a 45 or a 90 or something in-between?

[Obie]

I think it was supposed to separate while it was at max velocity of 1300 mph. The orbiter was supposed to light off and continue to orbit. The booster was supposed to coast down to a slower speed and then do a flip to head back for landing.

[TomK]

Sorry if I wasn't clear. The rocket was supposed to flip 180, separate, then the booster would go do "it's thing" for touchdown. I didn't mean the booster was going to stop and reverse it's already well established velocity. Inertia's a bitch.

If SpaceX has outlined their plans, I haven't read them. I'm just reading into what I saw and my rudimentary understanding of physics. I'd guess the booster was supposed to get clear, then slow itself down using the main engines so it'd descend back into atmosphere on a lower trajectory, then use the last of it's fuel to allow it to touchdown in a controlled fashion.

Yes, that's closer to what was planned but I don't think the 180-degree flip before separation was ever planned. Normally, the first stage stops when it runs out of fuel and the second stage then detaches leaving the first stage behind. The first stage will maneuver after this separation and start falling back toward earth and fire its engines again at some point to slow it down. It then shuts them off and free-falls back down to the Earth's surface, allowing the thickening atmosphere to slow it down. It's only when it's close to hitting the ground it will fire its rockets again to slow it down so much that it can land softly.

I suggest watching the following video to follow what I'm saying - it's a SpaceX launch with booster (1st stage) recovery.

https://www.youtube.com/live/iS9cT0vz3ng?feature=share&t=546

[dobanion]

Yeah, TomK, that's how it's historically worked. You just drop the booster as garbage behind you and say goodbye to it. Saturn V, and so many others. SpaceX is trying to bring the booster back and have it touchdown, so it needs to manuver AND preserve enough fuel to do so and retro burn into a soft touchdown. No small feat. I think at this point the exact details of how that ending alters the typical separation step, is conjecture, and I'm guilty of quite a bit of that.

In any case, the story has now shifted to two other things, which going forward are going to be more important for the future of this program.

1. The launch pad is wrecked. Not damaged, pretty much destroyed. Nothing blew up. The power of this rocket was enough to effectively disintegeate the concrete base of the pad in the 2-3 seconds it was burning before it cleared the tower. Seems NASA had the right idea 60 years ago when they had a diversion system for the rocket exhaust, along with a water dousing system.
2. The FAA is seriously pissed about everything that came back down after the rocket blew up (or self destructed, who cares).

[TomK]

Yeah, TomK, that's how it's historically worked. You just drop the booster as garbage behind you and say goodbye to it.

That's not what I wrote. They planned to recover the booster, it's just that they didn't plan to do the flip maneuver until the first stage had stopped firing its engines and had released the second stage, as they have done in most of their launches. The plan was always to recover the booster. The video I linked to shows the whole process.

[dobanion]

Ok, gotcha. Sorry for the confusion.

[HereOnThePrimalEdge]

October 25, 2023

Latest update on this launch and Hawaii splashdown is that its ready to go, pending FAA & Fish and Wildlife permits:

https://x.com/spacex/status/1716979479845953646?s=61

[TomK]

For whatever reason that video is silent. I unmuted it, everything else I'm using has sound but that doesn't. I don't use X/twitter so maybe there's a problem there but I can't think what it might be.

[terracore]

Looks like drone footage which would be silent and they didn't feel the need to add music or narration to it.

My wife wanted me to add music to some drone footage I shot and I was going to use ice cream truck music playing on an infinite loop but eventually common sense prevailed.

[TomK]

Well, yes, but I had assumed the link was going to tell me about the latest plans and about the fish and wildlife permits.