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SpaceX launches Starship v3 rocket

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Re: SpaceX launches Starship v3 rocket

#131

Post by adgjlsfhk1 »

redox99 wrote: post #13
ajross wrote: post #9

Earlier quoted context omitted.

Which is true, but at the same time: this is Starship Flight 12. The whole point of Starship is that it's a reusable vehicle with easy turnaround and quick maintenance. And in particular it's supposed to be different than the other reusable vehicle with easy turnaround and quick maintenance, which turned out to be sort of a boondoggle. Yet, they've now hand-built and destroyed twelve of these things across multiple r…

If you can afford it, I'm sure anyone developing a rocket would prefer to do it this iterative way. I don't really understand the complain.

The part that makes no sense to me is why they are going starship scale rather than falcon 9 scale. Had they done their prototyping on a rocket with 9 engines on the first stage and 1 on the second, they could have gotten to raptor 3 (and a falcon 9 replacement) while blowing up way fewer engines, launch complexes, etc. There's a reason Spacex started with the falcon 1 rather than the falcon 9. It's a lot cheaper to blow up fewer engines and smaller rockets while you're developing a new rocket engine.

Re: SpaceX launches Starship v3 rocket

#132

Post by b112 »

throwaway85825 wrote: post #73
EA wrote: post #68

Earlier quoted context omitted.

The tiles ablate. The shuttle returned from every mission with missing tiles.

The shuttle required long expensive refurbishment after each flight.

Just made me realise, this is just like the F-35.

Its turn around time is ridiculous, it has to be maintained with specialized equipment/hangers, along with external contractor assistance.

Compared to the Gripen, as an example, which can land on a freeway and be up in the air again in a few minutes.

One was designed to be used in war, in desperate scenarios, with no ability to coddle it. The other, the F-35? Is designed around milking the taxpayer as much as possible, and employing people in as many politician's states as possible.

The shuttle was like that, I think. Which is really sad.

Re: SpaceX launches Starship v3 rocket

#133

Post by adgjlsfhk1 »

aero-glide2 wrote: post #50
jmyeet wrote: post #46

It's worth remembering that, according to SpaceX's own filings, they've spent >$15 billion on the Starship program thus far with more to come. And SpaceX is burning cash still, particularly because Elon Musk bailed out his own bad decisions with Twitter and xAI with SpaceX stock, basically. Flight 12 was a relative success. Some engines failed to light but that's an unintended good test. Rockets are typically designe…

Revenue from xai renting to anthropic this year alone will be more than starlink and launch revenue

Revenue from selling money at a discount isn't generally considered a good strategy.

Re: SpaceX launches Starship v3 rocket

#134

Post by labcomputer »

adgjlsfhk1 wrote: post #125
SilverElfin wrote: post #110

Earlier quoted context omitted.

See my other comment. The vacuum engines are NOT on a gimbal. None of them. The sea level engines on starship and several of the engines on the booster are on a gimbal. But not the vacuum engines for space. EDIT: I cannot reply further in this thread, but my understanding is that the non vacuum engines are not intended to stay lit throughout the orbital flight in a typical mission. If they are, they can gimbal and co…

I think previous comment means "on a gimbal" as in "angled at a non completely prograde direction" (presumably angled such that each engine points through center of mass so that none of the engines impart a torque)

The person you’re replying to is trying to play rhetorical word games.

The upper stage has six engines. The outer three engines are “vacuum engines” (optimized for operation in space). The inner three engines are “non vacuum engines” (optimized for operation in the atmosphere, at sea level).

The outer three vacuum engines are not gimbaled, but the inner three sea level engines are. Thus, it is completely accurate to say that they gimbaled some of the engines to compensate for the engine failure.

Re: SpaceX launches Starship v3 rocket

#135

Post by generuso »

mh- wrote: post #119
MPSimmons wrote: post #81

Earlier quoted context omitted.

Consider for a moment the data requirements for the telemetry system that records those engine runs.

If there's any public info about this I'd love to read it.

Both SpaceX and NASA use LabView. NASA has a relatively detailed description of the engine test stands at Stannis:

https://scholar.google.com/scholar?q=NASA+Data+Acquisition+S...

https://scholar.google.com/scholar?q=Design+of+Electrical+Sy...

A typical test stand would have maybe a thousand channels of relatively slow data (pressures, temperatures, flow rates, valve states, etc), and maybe up to a few hundred of channels for essentially audio data from vibration sensors. This amounts to sub-gigabit per second data rate overall.

If very high speed video / multiple video cameras are used, this could generate massive data rates, but unless something interesting happens it is not clear how important this data is.

In flight, the telemetry data rate from the entire Falcon-9 used to be measured in megabits per second per stage, plus the video stream. It was not a huge amount of data. Presumably now with Starlink they send a lot more telemetry from Starship, but in flight the engines typically have far, far fewer sensors compared to the ground testing.

Re: SpaceX launches Starship v3 rocket

#136

Post by ChuckMcM »

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 issues, it looks like they should be able to do a full end to end flight. That's reasonable progress. Given the IPO this was a pretty important flight and I don't think they hurt it (like blowing up on the launch pad would have). So their one step closer it seems.

Re: SpaceX launches Starship v3 rocket

#137

Post by cwillu »

SilverElfin wrote: post #103
echoangle wrote: post #85

Earlier quoted context omitted.

They explicitly said that they have engine out capability on the ship in the stream.

That’s for the booster (the big lower part) not for starship (the upper part that continues to space). They were surprised to have a vacuum engine out. In space there’s no atmosphere so you can’t use fins or wings to change direction. And if the engines can’t move around, you only have thrust and gravity and the tiny attitude adjusters to direct your ship.

You're simply wrong. The non-vacuum-optimized engines on the upper stage are still functioning in a vacuum, and their ability to gimbal to offset the loss of one of the vacuum-optimized engines was planned for.

Re: SpaceX launches Starship v3 rocket

#138

Post by s1artibartfast »

globalnode wrote: post #117
itsthecourier wrote: post #114

Earlier quoted context omitted.

why won't it ever work?

Even if it landed perfectly how is it going to be rapidly reusable with all those tiles breaking and needing repair? Then if that problem was magically engineered-away through some sort of materials science breakthrough, it still makes more sense to me to keep your big ships in a space staging area and your smaller ones as atmospheric gophers.

Small ships are less efficient, especially leaving the gravity well. Thats the whole point

Re: SpaceX launches Starship v3 rocket

#139

Post by mullingitover »

amluto wrote: post #113
mullingitover wrote: post #77

Earlier quoted context omitted.

> At this point, the entire SpaceX project is a bet on telecommunications services, specifically direct-to-satellite handheld Internet. That's the only market that will recoup the program costs. There's also a military angle here. I'll leave it as an exercise for the reader to look into Musk's history with Michael D. Griffin from the Reagan SDI/'Star Wars' program.

It’s an awkward comparison, but F9 can deliver a payload to orbit at a slightly lower price per kg than a Tomahawk missile can deliver it to a target. Starship would be MUCH cheaper if the economics works out the way that SpaceX would like it to. Obviously a few hundred kg of payload in orbit are not equivalent to the same payload delivered directly to a target.

You don’t need very many kg delivered to target if it’s plutonium. The SDI program had the idea was that if you parked enough defensive weaponry in orbit then maybe mutually assured destruction wasn’t something you had to worry about. The only problem was that getting all that mass into orbit was prohibitively expensive.

Then the deputy director of the program met a young man named Elon Musk, and the rest is history.

Re: SpaceX launches Starship v3 rocket

#140

Post by mh- »

generuso wrote: post #135
mh- wrote: post #119

Earlier quoted context omitted.

If there's any public info about this I'd love to read it.

Both SpaceX and NASA use LabView. NASA has a relatively detailed description of the engine test stands at Stannis: https://scholar.google.com/scholar?q=NASA+Data+Acquisition+S... https://scholar.google.com/scholar?q=Design+of+Electrical+Sy... A typical test stand would have maybe a thousand channels of relatively slow data (pressures, temperatures, flow rates, valve states, etc), and maybe up to a few hundred of chan…

Very cool. Thank you!
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