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So you don't consider Elon Musk to be part of the engineering team at SpaceX?
Starship Flight 5: Launch and booster catch [video]
911–920 of 1001 posts
Re: Starship Flight 5: Launch and booster catch [video]
#912Earlier quoted context omitted.
10 minutes from 3h25m of this video shows launch and catch. Historic viewing :) https://www.youtube.com/watch?v=YC87WmFN_As&t=3h25m14s
This angle is even more impressive IMO https://x.com/kimbal/status/1845451222750306344
You can hear Elon Musk in the background.
Re: Starship Flight 5: Launch and booster catch [video]
#913Re: Starship Flight 5: Launch and booster catch [video]
#914Earlier quoted context omitted.
I thought the same, screamed out "ouch that doesn't look good!" right before the catch. The last part of the live stream they showed footage from a different angle and there it didn't look too bad though! For sure controlled. Scott Manley put out a tweet that they went down towards a non-tower position until they were at three engine controlled burn, and only then did the side shift.
Timestamp of the different angle?
Re: Starship Flight 5: Launch and booster catch [video]
#915Pretty impressive. The engineering team at SpaceX is really something. Some thoughts; The 'chopsticks catch' was amazing to watch. Seems like it adds a lot of risk and clearly the booster needs additional fire suppression systems :-) perhaps the tower could mount something that sprays the booster like the barges have for the F9 boosters. The heatshield held out for a much longer time, the asymmetric heating on the fl…
As to whether catching the booster adds risk - I'm not sure it does. First, to the extent the booster is out of position in the x (sideways) direction, the chopsticks can move to accomodate error. But actually I think this dimension is the easiest of the three, as the booster has plenty to time to null any error in this dimension. In the y direction (direction of travel towards the tower), the rails on the chopsticks…
I am really curious what the maximum wind speed allowed for a booster landing will be. Upon landing, it has a lot of windage and not nearly as much mass as during take-off.
I have experience with docking large boats and it does seem to be a bit similar. In the case of boats, wind is a big deal, and the booster has nothing "below the waterline" to slow down the effects of wind.
Re: Starship Flight 5: Launch and booster catch [video]
#916Earlier quoted context omitted.
> Second stage reuse seems the far more challenging problem. Sure, SpaceX has been doing first stage reuse for a long time now. But they have demonstrated landing the second stage successfully at sea twice now with the same sort of smoothness that they demonstrated once for the booster before they then caught the booster on the first real try. A partial list of unbelievably hard things that SpaceX has so far made see…
They have a history of pursuing solvable problems and abandoning those that were not working out or had better alternatives. Parachute recovery of the booster was abandoned in favor of propulsive landings. Catching fairings was abandoned for water proofing. Proposed Falcon and Dragon variants were abandoned as was Dragon propulsive landing. They abandoned carbon fiber construction and multiple concepts for Starship/H…
If the ceramic tiles aren't working out, I think they could try transpiration cooling (previously planned for Starship) or a metallic heat shield (was planned for VentureStar). Or some combination. There seem to be quite a few options.
Re: Starship Flight 5: Launch and booster catch [video]
#917Nothing could have prepared me for how that catch looked. I was sure the rocket was careening into the tower at the last second before it straightened out. The control algorithms must be incredible for the landing system to work within those small tolerances.
MIMO and nonlinear control theories are probably some of the hardest topics in all of engineering. SpaceX control system also has to compensate for the fuel moving inside their rockets so the control algorithms probably involve some kind of fast numerical fluid simulation. Another interesting thing SpaceX is doing is to use consumer-grade chips in triple redundancy configurations instead of using $100,000+ radiation-…
I'm not an engineer, but is there a reason why they can't french press (sans filter) the fuel toward the bottom of the tank as it empties?
Re: Starship Flight 5: Launch and booster catch [video]
#918The contrast between SpaceX's success at creating reusable rockets and Tesla's failure at FSD is pretty stark.
Re: Starship Flight 5: Launch and booster catch [video]
#919Earlier quoted context omitted.
I'm not sure how critical "catching" the booster is to reusability, but it does save weight by not needing legs for landing, and perhaps the booster suffers less stress this way? Note that the booster is not really being "caught" although this is the word it seems we're stuck with. It's really more like landing on the arms, since it throttles to a hover at that point.
I think saving weight is definitely one of the main issues, see those proportionally large legs on Falcon-9, I guess it simply doesn't scale on bigger vehicles like Starship / Heavy booster. Also, by catching the booster on site, they can even save the transportation and do the refurbishing on site, so even shorter turnaround time I guess.
Another way to save weight would be to make the booster out of carbon fiber instead of steel. I wonder whether they will do that eventually.
Re: Starship Flight 5: Launch and booster catch [video]
#920Pretty impressive. The engineering team at SpaceX is really something. Some thoughts; The 'chopsticks catch' was amazing to watch. Seems like it adds a lot of risk and clearly the booster needs additional fire suppression systems :-) perhaps the tower could mount something that sprays the booster like the barges have for the F9 boosters. The heatshield held out for a much longer time, the asymmetric heating on the fl…
I'm wondering if they'll be using the vertical equivalent of arresting gear on aircraft carriers[0]. See when fighter jets land on aircraft carriers? There's a cable that decelerates them. That, but for vertical landing. The way these chopsticks are set forces the booster into a dangerous, snake like maneuver (a SnakeX maneuver) at the last second from a vertical setting, to get into the chopsticks. This maneuver is…
One thing to note is that the "Snake" maneuver was designed to keep the tower safe during the test, and not forced on the rocket by the chopsticks.
The rocket was set to come down on the pad just in front on the tower and launch mount until the final 3-engine landing burn started. This kept the infrastructure safe until the last moment, but also required that lateral translation you referred to.