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From the little I could find on it, it sounds like the rocket actually landed... and then sorta kept landing until RUD. Is that right? There was more slam than

From the little I could find on it, it sounds like the rocket actually landed... and then sorta kept landing until RUD. Is that right? There was more slam than hover in this particular maneuver?

mikeash 10y ago
That's pretty much correct. One of the engines wasn't producing full thrust during the final landing burn. Since there's almost no fuel margin, the rocket ignites at the last possible moment with the goal of reaching zero speed right as it touches the ship. Reduced thrust means that it would touch the ship before it had fully braked. The live video from the ship didn't work well (something about satellite dishes makes them work poorly when there's a massive rocket blasting them with fire, apparently) but from the few frames that made it through, the rocket clearly managed to come to rest upright on the ship. There was a great deal of residual fire, everything was clouded in smoke and compression artifacts, and the last frame was from only about four seconds after touchdown. It's hard to tell exactly what was going on, but it looks like it hit hard, broke the legs or the fuel tank, and after a few seconds it exploded or fell over or both.
- cowkingdeluxe 10y ago
  Another thing to keep in mind this is another one of the launches where the 1st stage was coming in a lot faster (geosync orbit launch).
- infogulch 10y ago
  Reference: https://twitter.com/elonmusk/status/743097337782763521 https://twitter.com/elonmusk/status/743097337782763521 "Looks like thrust was low on 1 of 3 landing engines. High g landings v sensitive to all engines operating at max."
- schoen 10y ago
  I'm somehow reminded of the Monty Python line about building castles in a swamp: > When I first came here, this was all swamp. Everyone said I was daft to build a castle on a swamp, but I built in all the same, just to show them. It sank into the swamp. So I built a second one. And that one sank into the swamp. So I built a third. That burned down, fell over, and then sank into the swamp. But the fourth one stayed up. And that’s what you’re going to get, son, the strongest castle in all of England. SpaceX may be doing things in a slightly different order, but maybe eventually all of their castles, er, rockets are going to stay up on the landing pad. :-)
  - mikeash 10y ago
    That's hilarious, and a great comparison too. They'll get there! Fortunately they've figured out how to get paid even if they fail, so they can take their time getting it to work.
- calgoo 10y ago
  There is a satellite photo from 40min after the landing [1] and it looks like its still standing... So it might just have crushed the engines. [1] https://twitter.com/deimosimaging/status/743153542362439680 https://twitter.com/deimosimaging/status/743153542362439680
  - dtparr 10y ago
    There's some question as to what that actually shows. Here's one theory that shows it fallen over: https://twitter.com/NASASpaceflight/status/743182102875738112 https://twitter.com/NASASpaceflight/status/74318210287573811...
- mikeash 10y ago
  Update: they're now saying that it ran out of propellant before touchdown. Same basic result, but different cause.

From the little I could find on it, it sounds like the rocket actually landed... and then sorta kept landing until RUD. Is that right? There was more slam than hover in this particular maneuver?

mikeash 10y ago

That's pretty much correct. One of the engines wasn't producing full thrust during the final landing burn. Since there's almost no fuel margin, the rocket ignites at the last possible moment with the goal of reaching zero speed right as it touches the ship. Reduced thrust means that it would touch the ship before it had fully braked. The live video from the ship didn't work well (something about satellite dishes makes them work poorly when there's a massive rocket blasting them with fire, apparently) but from the few frames that made it through, the rocket clearly managed to come to rest upright on the ship. There was a great deal of residual fire, everything was clouded in smoke and compression artifacts, and the last frame was from only about four seconds after touchdown. It's hard to tell exactly what was going on, but it looks like it hit hard, broke the legs or the fuel tank, and after a few seconds it exploded or fell over or both.

cowkingdeluxe 10y ago
Another thing to keep in mind this is another one of the launches where the 1st stage was coming in a lot faster (geosync orbit launch).
infogulch 10y ago
Reference: https://twitter.com/elonmusk/status/743097337782763521 https://twitter.com/elonmusk/status/743097337782763521 "Looks like thrust was low on 1 of 3 landing engines. High g landings v sensitive to all engines operating at max."
schoen 10y ago
I'm somehow reminded of the Monty Python line about building castles in a swamp: > When I first came here, this was all swamp. Everyone said I was daft to build a castle on a swamp, but I built in all the same, just to show them. It sank into the swamp. So I built a second one. And that one sank into the swamp. So I built a third. That burned down, fell over, and then sank into the swamp. But the fourth one stayed up. And that’s what you’re going to get, son, the strongest castle in all of England. SpaceX may be doing things in a slightly different order, but maybe eventually all of their castles, er, rockets are going to stay up on the landing pad. :-)
- mikeash 10y ago
  That's hilarious, and a great comparison too. They'll get there! Fortunately they've figured out how to get paid even if they fail, so they can take their time getting it to work.
calgoo 10y ago
There is a satellite photo from 40min after the landing [1] and it looks like its still standing... So it might just have crushed the engines. [1] https://twitter.com/deimosimaging/status/743153542362439680 https://twitter.com/deimosimaging/status/743153542362439680
- dtparr 10y ago
  There's some question as to what that actually shows. Here's one theory that shows it fallen over: https://twitter.com/NASASpaceflight/status/743182102875738112 https://twitter.com/NASASpaceflight/status/74318210287573811...
mikeash 10y ago
Update: they're now saying that it ran out of propellant before touchdown. Same basic result, but different cause.