totm nov 2023 SpaceX Discussion Thread

[RealKerbal3x]

2 minutes ago, zolotiyeruki said:

A few seconds before ...er....touchdown, lots of green flames from the engine on the left.   I seem to remember that being associated with lots of copper combusting that shouldn't be combusting...

Could have been that one engine failed and that was the thrust that they needed to land.

[Flying dutchman]

My watch says my Heartbeat got up to 165bpm watching the  lifestream.. :p

[sevenperforce]

If anyone wants to replay the flight only, here's a link to the terminal count:

 

[CastleKSide]

My thought on the green was actually the ignition fluid. Like maybe the TeaTeb or whatever it is called was leaking into the engine?

[Geonovast]

1 minute ago, Brotoro said:

Watching replay. They had two engines firing on the landing. Did it crash because they needed all three?

One of the two that lit for landing looks like it cut out after the flip.  Also the green flame is probably a concern.

I look forward to Scott Manley's video on it.

[EnderKid2]

I think that green flame is from the engine starting fluid. Perhaps engine-out and a failed relight?

[Flavio hc16]

Just now, CastleKSide said:

My thought on the green was actually the ignition fluid. Like maybe the TeaTeb or whatever it is called was leaking into the engine?

we have seen the same from the starhopper 150m hop, and it meant that probably it was destrying itself

[sevenperforce]

2 minutes ago, ExtremeSquared said:

I am wildly impressed that the totally insane aerodynamic bellyflop and flip plan resulted in an upright, center-of-pad, and non-terminal-velocity landing. Wildly impressed.

Ridiculously, wildly impressed. Everything worked.

3 minutes ago, JoeSchmuckatelli said:

I'm rewatching - why is Senate's burn so clean?  I'm used to a smoke /contrail column under a Rocket 

Methalox produces just water and CO2, nothing else. The only thing cleaner is hydrolox, which produces only water.

3 minutes ago, RealKerbal3x said:

4 minutes ago, RealKerbal3x said:

[quoting @zolotiyeruki] A few seconds before ...er....touchdown, lots of green flames from the engine on the left.   I seem to remember that being associated with lots of copper combusting that shouldn't be combusting...

Could have been that one engine failed and that was the thrust that they needed to land.

Yes, after rewatching a few times that's my best guess as well. It can do a two-engine landing burn but I'm guessing they timed it for a three-engine landing burn. 

[StrandedonEarth]

I thought it was spark ignition, or are they not there yet? So probably the engine consuming itself 

[Flying dutchman]

The concept actually works!!!!!!

[sevenperforce]

3 minutes ago, CastleKSide said:

My thought on the green was actually the ignition fluid. Like maybe the TeaTeb or whatever it is called was leaking into the engine?

Merlin uses TEA-TEB but Raptor does not -- it uses electric gas-gas torch igniters. 

[Entropian]

I have only just now composed myself.  I have only three words: That. Was. Awesome.

[Lewie]

From what I saw, it looked like the raptor in the back and the right went out right before touchdown. Also....why on earth did that one raptor go green??

That was awesome.....can’t believe it *almost* worked!

[RCgothic]

1 minute ago, sevenperforce said:

Merlin uses TEA-TEB but Raptor does not -- it uses electric gas-gas torch igniters. 

Good catch. Yes it looks like an engine out and the engine was required.

An almost totally successful test otherwise!

[Entropian]

I can't believe the bellyflop actually worked.  I totally expected it to be unable to pull out of the bellyflop, but it actually crashed upright.  SN9 up next!

[Codraroll]

I love how the two onboard camera views freeze upon "landing", then the main feed takes over the entire screen as if someone at video control wanted to say "umm ... let's focus on the one camera that's still intact".

It's also interesting to watch the pad afterwards and see what the exhaust did to the ground next to the concrete. Like a high-pressure washer on soft soil, it dug a trench in literally a second. Wonder if the pad was just a little bit too small to avoid that, or if they would have hit the pad dead on if all three engines were working.

But yeah, overall, this has to be some of the craziest, most bonkers stuff (in a positive sense) a private company has ever pulled off.

[Serpens Solidus]

hopefully that means no issues with the raptors

 

[Ultimate Steve]

I have no words!!!!!

[RCgothic]

 

Header tank pressure low leading to landing overspeed. They got all the data they need!

[Lewie]

The bellyflop and flip maneuver ‘worked’! Spacex sure had come a long way....this is insane! Really hoping to see sn9 take to the sky soon

@Dirkidirk you thinking about changing your profile pic? 

[Kevin Kyle]

Born in 57, been watching spaceflight all my life. That was simply incredible.

[JoeSchmuckatelli]

The weird thing was that the engine that did not light - was the last one that was on during the flight (presuming the camera angle was correct).  Oddly, the first one that shut down and caused the fire relit... but the last Raptor standing gave up the ghost at the end.

 

Also -- thanks for the answers about the green flame before I could ask!

[Brotoro]

Liftoff?  Check!

Controlled ascent?  Check!

Transition to skydive?  Check!

Stable and controlled skydive.  Check!

Restart engines (I presume from header tanks).  Check!

Kick around maneuver?  CHECK!! (And I was out of my seat screaming)

Targeted landing pad?  CHECK!!

Landed nose up?  CHECK!!

Successful landing?   Needs improvement. 

[Elthy]

That was one of the coolest things ive seen in my whole life. Beginning with the liftoff, those blue flames are beautiful. I cant imagine how Superheavy will look like with way more engines, especialy at night.

 

Extremly impressive they got the bellyflip right on the first try, its one of the most extreme maneuvers in the history of flight. Also its funny the engine that shut down first on the way up (which looked to violent) made it down to the ground, while engine 42 that went all the way up never reignited (propably on purpose).

[sevenperforce]

Rewatching for the fourth time at 25% speed.

Raptor SN42 is never ignited; just the other two. They provide the entire kick-flip torque.

At T+6:32, a few green flashes appear on the left-hand Raptor relative to SN42.

By T+6:37, the exhaust from the left-hand Raptor is bright green:

It appears to correct a moment later and becomes the familiar pink-purple again:

One second later the green has returned and it's almost violent in its hue:

The green disappears, and the other engine, on the right, is shut down, apparently because they were planning on a 2-1 landing burn:

The green comes back, this time to stay, and becomes so bright that it fills up the entire skirt section. The length of the plume is noticeably shortened as copper residue fills the exhaust, which in turn is saturated with soot:

So it looks like they planned a 2-1 landing burn, but the engine they chose to land with had an anomaly on restart that led to it eating itself from the inside out over a period of about 4 seconds.

EDIT: I hadn't seen Elon's tweet when I posted this, yet. But that green flame and sooty exhaust is clearly off-nominal. If the fuel tank header pressure was low, then could that have caused insufficient flow in the preburners, resulting in an oxygen-rich burn-through?

Edited December 9, 2020 by sevenperforce