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Either both, as a repeat of SN10 because it lands a bit too hard, or a good landing. I think they'll do everything they can to prevent it blowing up again or RUD-ing on impact

Edited by Spaceception
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7 hours ago, StrandedonEarth said:

Seriously though, the initial reports about the SN11 flight were confusing. First they said it self-terminated, then they said it had a RUD event. In retrospect, I’m guessing the telemetry said the FTS activated, then after further review they saw that a RUD happened first. I’m guessing the FTS activated when the computer sensed something was very, very wrong (after the RUD). 

But everyone probably figured that out for themselves. 

I'm pretty sure that they did not expect the FTS going off during this flight, as such, the FTS auto-triggering would be a RUD.

While it is possible that there were multiple events, I see no reason why they might not both be referring to the same event in different ways.

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Oh, the Falcon 9 upper stage is pressure fed? Huh. I knew krestel was, but not the V-Merlin.

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7 minutes ago, Lewie said:

Oh, the Falcon 9 upper stage is pressure fed? Huh. I knew krestel was, but not the V-Merlin.

No, it uses a turbopump as well, even non-pressure fed engines need to have some sort of pressurization mechanism, or this could have been for the cold gas RCS

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5 hours ago, insert_name said:

COPV from Falcon upper stage recovered from Washington state

 

What happened here? I assume they lost control over upper stage after satellite deploy but before it was in position to do its reentry burn over south pasific. 

 

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Ive heard it didnt have enough fuel for a safe reignition to deorbit, trying with to little fuel could result in an explosion. So they decided to let it decay on its own.

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I’d certainly want to keep the thing if it showed up in my backyard, but I suppose that’s not for everyone and if it took out some of my stuff I’d have to relinquish it in order to claim damages.

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11 hours ago, Lewie said:

Do you guys think SN15 will stick the landing or RUD?

I’m betting on a landing

Not betting, but expect a RUD (80% chance). The other 20% is either a delayed RUD (like SN10) or a good landing.

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11 hours ago, Lewie said:

Oh, the Falcon 9 upper stage is pressure fed? Huh. I knew krestel was, but not the V-Merlin.

As @insert_name said, that COPV isn’t for pressure-feeding. It looks too large to be the nitrogen tank for the cold-gas thrusters so it has to be the helium ullage tank.

The Merlin Vacuum engine uses the same gas generator turbopump as the Merlin SL engine, but you still need something to replace the lost volume in the tanks, and so they use a helium tank. The helium passes through a heat exchanger near the engine to warm up before being exhausted into the tanks to maintain ullage. Both stages of the Falcon 9 use this system.

This was the cause of the failure that exploded AMOS-6.

Starship won’t use helium COPVs because it uses autogenous pressurization — a small portion of the LOX and liquid methane are vaporized in a heat exchanger downstream of the turbopump outlet and routed back into their respective tanks. You can’t do this with kerosene because kerosene doesn’t vaporize as nicely as methane. 

Starship will, however, use COPVs to hold gaseous methane and GOX to supply the pressure-fed hot-gas thrusters and to restart the engines after coast.

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2 hours ago, sevenperforce said:

As @insert_name said, that COPV isn’t for pressure-feeding. It looks too large to be the nitrogen tank for the cold-gas thrusters so it has to be the helium ullage tank.

The Merlin Vacuum engine uses the same gas generator turbopump as the Merlin SL engine, but you still need something to replace the lost volume in the tanks, and so they use a helium tank. The helium passes through a heat exchanger near the engine to warm up before being exhausted into the tanks to maintain ullage. Both stages of the Falcon 9 use this system.

This was the cause of the failure that exploded AMOS-6.

Starship won’t use helium COPVs because it uses autogenous pressurization — a small portion of the LOX and liquid methane are vaporized in a heat exchanger downstream of the turbopump outlet and routed back into their respective tanks. You can’t do this with kerosene because kerosene doesn’t vaporize as nicely as methane. 

Starship will, however, use COPVs to hold gaseous methane and GOX to supply the pressure-fed hot-gas thrusters and to restart the engines after coast.

Thanks! I knew that gases such as helium were used for tank pressurization. Thanks for the insight!

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12 hours ago, kerbiloid said:

Based on its size, Brobdingnag's.

LOL. I'd almost forgotten about that book...

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