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SpaceX launches Starship v3 rocket

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Re: SpaceX launches Starship v3 rocket

#201

Post by Gagarin1917 »

ChuckMcM wrote: post #136
Laremere wrote: post #15

Summary from my watch: - Launch roughly on time, after a scrub yesterday. (Sounds like the scrub was due to ground equipment, most notably the water system.) - Initial ascent was good, but then one engine on the booster went out. - Relight of the booster's engines after stage separation for the boost back burn failed. Engines did light again for a landing burn, but seems to have hit the water harder than expected and…

Nice work by SpaceX engineering. Good summary. The booster appeared to hit the water at 1400 km/h (a bit under 900 mph) so not really survivable :-). Engine out on ship seems to left them with just enough fuel to land but not enough to do the hover thing (simulates being caught by chopsticks). They notched it down to two engines (vs planned 3) on the landing it seems? Basically if they can figure out the engine issue…

Landing on two engines was the plan.

V3 Raptors are too powerful, they no longer need three engines to land. They are only going with two from here on out.

So I think it’s unlikely that they altered any aspect of the landing test due to lighting only two engines… as they was the plan anyway.

Re: SpaceX launches Starship v3 rocket

#203

Post by syncsynchalt »

jordanb wrote: post #176
dingaling wrote: post #115

Earlier quoted context omitted.

> The word "live" is doing a lot of work here A latency of a few seconds for streaming video compared to several months for a still photo from the Shuttle seems an entirely valid use of 'live'.

The difference here is a matter of AV technology improvements in the last 40 years.

The difference is having high-bandwidth signal pointed up / away from the wall of plasma.

Re: SpaceX launches Starship v3 rocket

#204

Post by syncsynchalt »

modeless wrote: post #180
db48x wrote: post #179

Earlier quoted context omitted.

Keep in mind that all the prior flights had deliberately missing tiles specifically to test how bad the damage would be. This one had no missing tiles so it should have essentially no damage to the hull.

I think the worst damage on previous flights was often not related to the missing tiles.

I think it was due to voids in the hinge area causing localized plasma impingement and heating. The v3 design has a more continuous shape around the hinges.

Re: SpaceX launches Starship v3 rocket

#205

Post by oconnor663 »

irjustin wrote: post #52
Laremere wrote: post #15

Summary from my watch: - Launch roughly on time, after a scrub yesterday. (Sounds like the scrub was due to ground equipment, most notably the water system.) - Initial ascent was good, but then one engine on the booster went out. - Relight of the booster's engines after stage separation for the boost back burn failed. Engines did light again for a landing burn, but seems to have hit the water harder than expected and…

The videos were incredible. My favorite part was watching the booster flip in such clarity. Normally we don't get full view of it, let alone 4k.

Scott Manley pointed out that it seemed to flip in the wrong direction, with one of the grid fins passing through the plume and inducing a roll. Will be interesting to hear more about that.

Re: SpaceX launches Starship v3 rocket

#206

Post by isodev »

Laremere wrote: post #15

Summary from my watch: - Launch roughly on time, after a scrub yesterday. (Sounds like the scrub was due to ground equipment, most notably the water system.) - Initial ascent was good, but then one engine on the booster went out. - Relight of the booster's engines after stage separation for the boost back burn failed. Engines did light again for a landing burn, but seems to have hit the water harder than expected and…

And the “side effect” of polluting the ocean? SpaceX is more of a let’s only do things half way kind of company it seems.

Re: SpaceX launches Starship v3 rocket

#207

Post by syncsynchalt »

rogerrogerr wrote: post #120
glzone1 wrote: post #112

Does anyone know how important hot staging is? It seems to give the booster a real kick - what's that do to turbo's and fuel movement? You've got hot exhaust onto cold cryo fuel tank header? You've got to carry more mass in terms of protection for the tank? Is doing MECO and then push and then get 100 yards apart or something before second stage / ship engines kick on a big enough penalty to justify all the extra com…

All the velocity you lose in any kind of throttle back is velocity you never get back. It hurts you the entire rest of the flight.

aka "gravity losses". Every second you're not (yet) in orbit you're losing dv / cargo capability.

Re: SpaceX launches Starship v3 rocket

#208

Post by ChuckMcM »

Gagarin1917 wrote: post #201
ChuckMcM wrote: post #136

Earlier quoted context omitted.

Nice work by SpaceX engineering. Good summary. The booster appeared to hit the water at 1400 km/h (a bit under 900 mph) so not really survivable :-). Engine out on ship seems to left them with just enough fuel to land but not enough to do the hover thing (simulates being caught by chopsticks). They notched it down to two engines (vs planned 3) on the landing it seems? Basically if they can figure out the engine issue…

Landing on two engines was the plan. V3 Raptors are too powerful, they no longer need three engines to land. They are only going with two from here on out. So I think it’s unlikely that they altered any aspect of the landing test due to lighting only two engines… as they was the plan anyway.

Hmm, I've seen data that landing the booster on 2 engines was the plan, but hadn't seem similar things about Starship. The difference is the chamber pressure you need in the individual engines. Lower chamber pressure has, in the past, been easier to modulate for precise control. Do you know if they've done any white papers or patents on V3's flow aeronautics?

Re: SpaceX launches Starship v3 rocket

#209

Post by oconnor663 »

fooblaster wrote: post #182
itsthecourier wrote: post #114

Earlier quoted context omitted.

why won't it ever work?

The hardest problem in the entire design had yet to be solved. Having a robust human rated tile system that can be rapidly turned around is a huge engineering challenge that kind of breaks the whole point of the design if it doesn't work. I wouldn't be surprised if they eventually give up and go back to a cheaper throw away second stage, or throw out the tile design completely and try for some evaporative cooling app…

Bear in mind that a lot of what's happening to the tiles now is deliberate experiments to see how much weight they can shave off and how many failed tiles they can survive. Given that the vehicle is routinely surviving reentry at this point, it doesn't seem "hard" to make the tiles more robust by paying for it with added weight. The question is whether they'll have enough weight budget to pay for it? But at this point...probably? Not my area ofc.

Re: SpaceX launches Starship v3 rocket

#210

Post by fooblaster »

oconnor663 wrote: post #209
fooblaster wrote: post #182

Earlier quoted context omitted.

The hardest problem in the entire design had yet to be solved. Having a robust human rated tile system that can be rapidly turned around is a huge engineering challenge that kind of breaks the whole point of the design if it doesn't work. I wouldn't be surprised if they eventually give up and go back to a cheaper throw away second stage, or throw out the tile design completely and try for some evaporative cooling app…

Bear in mind that a lot of what's happening to the tiles now is deliberate experiments to see how much weight they can shave off and how many failed tiles they can survive. Given that the vehicle is routinely surviving reentry at this point, it doesn't seem "hard" to make the tiles more robust by paying for it with added weight. The question is whether they'll have enough weight budget to pay for it? But at this poin…

"surviving reentry" and being reusable are two very different things, particularly if this is to become human rated.
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