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https://twitter.com/nasaspaceflight/status/1599154206195478528

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MegaBay Stablemates.

Booster 7 (left). Booster 9 (right).

Retired pals in the Rocket Garden.

nsf.live/starbase
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And from Nomadd's photo above, looks like it's traversing the entire berm top.
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Orbit at epoch Dec 3, 09:52 UTC:
2022-163A/54381 in 898 x 912 km x 67.14
and Object 54383 (Kosmos 2566?) at epoch Dec 3, 02:45 UTC
2022-163C/54383 in 896 x 911 km x 67.14
Well... Looks like I was right.
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Photos taken yesterday and posted today by NASA Johnson
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Blowout panels are at the bottom. Rate of fill of the tank is controlled by controlling the flow of gas out the top valves. This is like the ballast tanks on a submarine. Yes, I know you compute your EDL to end up with almost empty tanks. I'm proposing a brief hover about a meter above the surface to empty the LOX tank all the way. If you blow the blowout panels while they are still at or just above the sea surface (or within a foot of the surface from below) the final bit if LOX will blow out before the water begins to flow in. The only remaining cooling in capacity in the system is in the stainless steel, and cannot create an ice plug if the blowout panel is big enough.

Blowouts anywhere pretty much imply pyros to blow them, don't they?  Pyros aren't necessarily bad, especially if the number of crewed flights is fairly modest compared to the number of robotic ones (a good assumption).  But pyros in a LOX tank don't sound wonderful, especially if the probability of an uncommanded blow-out is >0.01%.

You can't run the engines until the lines go dry; it'll make the turbopumps explode, which is a bad property during a landing--even a crash-landing.  The question is whether the sump holds 100-200kg of LOX, or whether it holds 1-2t.  The former isn't a big problem, the latter is.

Blow-out while still in the air might work, but you have to have the engine turbopumps shut down (i.e. preburners off) before you can depressurize the tank, and that doesn't leave much time for LOX to drain out away from the blow-out inlets.  Also, you want the tank pressurized on impact, even from a meter or two, because you don't want it to crumple or break open.

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So now we have our ship vertical with the engines just in the water, engines off, and just beginning to fall by gravity into the water. The panels blow and the last LOX blows out across the surface and the panels become submerged, so water begins to flow in. As gravity accelerates the drop into the water, the remaining O2 begins to compress (and heat) as water flows in, and the rate of drop eventually decreases as buoyancy counteracts gravity. The magical control system regulates the flow of gas out of the top valves to achieve the correct amount of bouyancy, bringing the whole system to a halt just before it would begin to rebound toward the surface.

I think you want an uncontrolled vent that pops at the same time as blow-out, because the goal is to get seawater in as quickly as possible.

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If at this point we are still topheavy, we are still being held vertical by the reaction wheel and RCS, and we can begin dumping methane since we are no longer spewing O2 all over the place.

Is the issue that you need to flood the methane tanks as well?  Because dumping methane into an atmosphere with oxygen in it, at what's more-or-less a crash site, doesn't sound like a great plan, LOX or no LOX.

However, don't put heavy payloads on crewed flights.  I haven't done the math, but I suspect that your CoG is now underwater if the crew module is the only payload and weighs <20t, the LOX tanks are flooded and the thrust structure and engines are dangling down.

So:  Not to give you a hard time, but how does this help pad abort?  For that matter, how does it help survive a failed flip maneuver?  You have to cover all the survivable abort contingencies, or it's not worth it.
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Or you sacrifice some performance to do the flip early.

Separating the crew every mission sounds like a recipe for cost and unreliability.

Technically some might be crew, but really, they are all just passengers sort of like Paratroopers are passengers in a C130.
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Photos of S25 today in RGV show that they're welding shut the payload dispenser door on that one, too, like S24.
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https://twitter.com/nasa/status/1599130851379359744

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Can we fix it? Yes, we can 🔧

Astronauts Josh Cassada and Frank Rubio have successfully installed Roll-Out Solar Array on the starboard truss structure of the @Space_Station. They have also disconnected a cable allowing restoring a power channel to 75% of its operating capacity.
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The original problem:After a vertical emergency water landing,  a Starship may not survive a topple to a horizontal floating position.
Proposed solution: land vertically and stay vertical using RCS and/or reaction wheel while sinking vertically to a "spar buoy" position by flooding the LOX tank. Starship will not topple at all: it will float vertically.
Objection: inrushing seawater will freeze when it hits the LOX, blocking the valve
Solution: use large blowout panels at the base instead of simple valves to allow dump of residual LOX and seawater ingress.

There is a video demonstration of F9 surviving a topple, even though it was not designed for it.

Look and see if first order equations prohibit survival from a topple.  They don't.   It looks pretty reasonable in fact.  Which is why that F9 survived despite there being zero design intent and in general having a much weaker construction and pressurization than a Starship.

Next step is to try and see if toppling will destroy (meaning explode) a Starship IRL.  Hopefully we get to find this out within the next month or two.

Then keep repeating IRL.  I suspect we'll see a couple of repeats of water landings.

The chain of causation I see you citing for why you are doing the design sets off every system design engineer alarm bell my brain has.   The alarm bell connected to "best part is no part".
I happen to agree with you, and I think the topple is likely to just work. I was looking for the simplest alternative if the topple does not work, since there are several posts here that raise this concern. Upthread you will see that I also think there is a trajectory that brings Starship in to zero velocity at water level but already at an angle, so the topple does not start at vertical. This is also a "best part is no part" improvement.
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