Wiki Super Heavy/Starship - General Development Discussion

[mongo]

New flight plan for the NASA observation plane shows a 12:51 central takeoff 2:17 central landing.
SN8 flight is then in the 1-2 time block central 2-3 ish eastern.
I need to move some meetings...

 

[mongo]

NASA flight plan updated to 2:30 central 3:30 eastern takeoff.
So 3 central 4 eastern appoximate test flight time.

 

[e-FTW]

SpaceX stream live in 5!

 

[diplomat33]

Countdown on hold. New T-0 is for about about 1hr07mn from now (4:40pm CST). Rumor is that there was a range violation.

 

[diplomat33]

THAT WAS AMAZING!!! THANK YOU SPACEX!!

 

[Zaxxon]

Not often that you get a successful launch and a fireball. Awesome stuff. Congrats, SpaceX!

 

[GWord]

That was exciting. Came in a little hot on the landing. Must have been programmed by Navy pilots.

 

[808?]

And now for our next trick, SN9!

 

[diplomat33]

That was exciting. Came in a little hot on the landing. Must have been programmed by Navy pilots.

Yeah, it looked like there was a problem with the raptor engines. They shut down mid flight and it looked there was a fire too. And then it looked like the raptor engines did not reignite properly, causing SN8 to hit the ground too fast.

 

[willow_hiller]

Yeah, it looked like there was a problem with the raptor engines. They shut down mid flight and it looked there was a fire too. And then it looked like the raptor engines did not reignite properly, causing SN8 to hit the ground too fast.

Reading through some comments on /r/SpaceX, some people think the engine shutdowns were intentional. But most agree that the green flame at landing likely meant the engine was burning itself (copper) and therefore didn't achieve 100% thrust.

EDIT: Tweet from Elon implies the accent was a success: https://twitter.com/elonmusk/status/1336808486022258688?s=20 maybe the engine cutoffs were a part of that "switch to header tanks" test?

 

[diplomat33]

Reading through some comments on /r/SpaceX, some people think the engine shutdowns were intentional. But most agree that the green flame at landing likely meant the engine was burning itself (copper) and therefore didn't achieve 100% thrust.

What I find incredibly exciting is that other than the engine issue, Starship performed admirably. It successfully launched, reached the target altitude, did the belly flop, slowed its descent with the flaps, flipped vertically again and aimed correctly at the landing pad. If the engine reignition had worked correctly, it probably would have landed perfectly. Overall, I would say it is a successful proof of concept.

 

[JohnSnowNW]

Reading through some comments on /r/SpaceX, some people think the engine shutdowns were intentional. But most agree that the green flame at landing likely meant the engine was burning itself (copper) and therefore didn't achieve 100% thrust.

EDIT: Tweet from Elon implies the accent was a success: https://twitter.com/elonmusk/status/1336808486022258688?s=20 maybe the engine cutoffs were a part of that "switch to header tanks" test?

I thought that green flame was from trying desperately to relight the third engine.

 

[Zaxxon]

https://twitter.com/elonmusk/status/1336809767574982658?s=20

Fuel header tank pressure was low during landing burn, causing touchdown velocity to be high & RUD, but we got all the data we needed! Congrats SpaceX team hell yeah!!

 

[Olds442]

that was awesome to watch. so many little successes in that test. congrats SPACEX!

who doesn't love a huge rocket explosion where nobody gets killed? freaking awesome.

 

[JohnnyEnglish]

This looked a really good test. The launch/ascent seemed smooth - I assume the switch to 2 engines and then one engine was planned - and the thing that most impressed me was the transition to the skydiver mode. RCS control was good. Stable skydiving. A good rotation during the landing burn but clearly not enough deceleration. Not sure how many engines they were intending to use but when I watched it at 0.25x it seemed that only 2 engines had relit. The one nearest the camera did not seem to relight.

It seems they have proved the concept which is probably the most important thing. Even the approach to the landing seems to work - they just need to get more thrust for that final stage.

Wow. Really went so much better than expected for a first attempt at something so complex. Well done SpaceX

Edit: Just seen the tweet from Elon posted above. If it was just low header tank pressure it should be straightforward to fix for SN9!

 

[mongo]

Reading through some comments on /r/SpaceX, some people think the engine shutdowns were intentional. But most agree that the green flame at landing likely meant the engine was burning itself (copper) and therefore didn't achieve 100% thrust.

EDIT: Tweet from Elon implies the accent was a success: https://twitter.com/elonmusk/status/1336808486022258688?s=20 maybe the engine cutoffs were a part of that "switch to header tanks" test?

Engine shutdowns on ascent may have been due to weight vs thrust throttling limits. Plus testing the transitions.

I thought that green flame was from trying desperately to relight the third engine.

Raptor uses torch ignitors, not TEA/TEB, exhaust should not be green

 

[diplomat33]

Just imagine when we get the finished Starship that is fully validated for human flight! It is going to be so epic!

 

[diplomat33]

and the thing that most impressed me was the transition to the skydiver mode.

Me too. Seeing Starship transition to skydiver mode was my favorite part.

 

[e-FTW]

My god that was AWESOME! We have never seen anything like this, belly-flop, flaps, fins, the landing maneuver. Just mind blowing. This looks like the future!

If you replay it from this timestamp, at 1/4 speed you will see the exact sequence of engine deaths:
#1 was already down from the ride up
#2 died shortly after relight
#3 was already burping up copper on relight (watch the green flames), looking for the Rolaids, but it tried hard anyway (watch it gimbal like crazy). But it went all green and was never enough to do this all by itself it seems.

Play from here at quarter-speed, it is pretty clear:

 

[e-FTW]

Re-light, but just one goes:

2 seconds later joined right-most. The one closer to camera never came back on. Left-most already showing green flames.

The late comer flames out pretty quick, leaving a single engine (let's call it "Greenie") that was burning copper internals to do the job.

Greenie then goes all out HULK but that was not enough to stick the landing. Someone needs to turn the gravity down.