SpaceX Falcon 9 historic landing thread (1st landing attempt & most recent missions)

Looks like a stack of pizzas.....SPACE pizzas!

They could transport them frozen. Just add reentry to cook .

Launch postponed to Thursday May 16, 10:30 PM EDT.

Webcast:

Postponed again, for a week or so:

"SpaceX is postponing our launch of 60 Starlink satellites to update satellite software and triple check everything again--always want to do everything we can on the ground to maximize mission success. The next launch opportunity is targeted for about a week (exact date TBD)."

bumped again. Those pizzas are going to get cold!
https://twitter.com/SpaceX/status/1129181397262843906

Have we discussed that ring that falls off the 2nd stage nozzle shortly after ignition on every flight? Do we know what that's about?

Just a stiffener, I had thought?

Yeah, it's a stiffener band. The clever ultra-complex release mechanism for it is.....that a key piece where the ends of the band are joined, melts from the nozzle heat (let's say something like a nylon bolt, but I do not know other than it melts) and lets the band slip away shortly after ignition. When the engine does begin to ignite, you can see the nozzle "wobble" a bit out of round, so that's one reason they need it, otherwise there would be a risk of damage to the lower end of the nozzle. That nozzle extension (for vacuum operation) is pretty flimsy.

That's clever. I suspect they are increasing the natural frequency of the bell by applying the stress to it. Alternatively it could be for mitigating a particular mode of vibration. A third option would be do add mass to the bell to decrease frequency, I suppose, but I doubt it. It is obviously there to solve a problem of some sort .

RocketGeekInFL said:

View attachment 383690 View attachment 383691

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And that is???

I am curious to know how they will take the weld distortions out of the one on the left and the bumps and dings out of the one on the right. Thin wall structures, even pressurized ones, aren't very forgiving when it comes to buckling.

OverTheTop said:

It is obviously there to solve a problem of some sort .

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Yeah, some kind of start-up transient needs to be managed, I guess. That nozzle does wobble a bit until things settle.

What's puzzling to me is this: Why do they feel the need to discard it once that job is done? There must be some reason why they chose to do that instead of just letting it stay attached.

(hmmm, does this mean rocket science really IS hard? )

cvanc said:

What's puzzling to me is this: Why do they feel the need to discard it once that job is done? There must be some reason why they chose to do that instead of just letting it stay attached.

(hmmm, does this mean rocket science really IS hard? )

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Dumping a little mass so they can get a hair more payload capacity to orbit or use a hair less fuel to get the same payload to orbit?

I know, right? Who knew that rocket science was hard?

If it was left on the inside of the bell, might it make a turbulent spot in the flow, collect heat and burn through the bell in an uncontrolled way?

dhkaiser said:

And that is???

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Starship construction site in Florida

Charles_McG said:

If it was left on the inside of the bell, might it make a turbulent spot in the flow, collect heat and burn through the bell in an uncontrolled way?

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It's mounted on the outside of the nozzle.

cvanc said:

What's puzzling to me is this: Why do they feel the need to discard it once that job is done? There must be some reason why they chose to do that instead of just letting it stay attached.

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I would suspect it’s not made of an expensive alloy, so it’s going to fail shortly after ignition.

cvanc said:

What's puzzling to me is this: Why do they feel the need to discard it once that job is done? There must be some reason why they chose to do that instead of just letting it stay attached.

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No point in lugging that mass along needlessly when it is SO easy for it to release itself when it is no longer needed.

OK, the Starlink launch is scheduled now for Thursday night the 23rd, at 10:30 PM EDT (window opens).

For those with a WSJ subscription https://www.wsj.com/articles/spacex...falsified-reports-prosecutors-say-11558576047

About to launch:

Any opinion on the mylar pulsing? Don't recall that on any other flight.

I watched the replay. It wasn't clear if they got the booster back. Video problems after the entry burn. Any word?

Booster landed fine and the satellite deployment was good. Very unusual, they just drifted apart. Eventually they will use ion thrusters to move them into place.

Tony

dhbarr said:

Any opinion on the mylar pulsing? Don't recall that on any other flight.

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Do you mean on the second stage in the engine views? Yeah, that’s fairly common.

Marc_G said:

I watched the replay. It wasn't clear if they got the booster back. Video problems after the entry burn. Any word?

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There was a brief shot showing the first stage landed on the drone ship shortly after the second stage’s first engine cutoff.

A couple of tweets, looks like all 60 satellites are online and both halves of the fairing were recovered.

https://mobile.twitter.com/SpaceX/status/1131765246664646657

Celestial Buddy Watched last night

Great shot Paul

RocketGeekInFL said:

Celestial Buddy Watched last night

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And you didn't even turn him around? rude

I can not take credit for the shot, but yes, he should have been turned around.