Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

SpaceX launches Starship v3 rocket

space.com

Post reply on HN
Print view View original

261–270 of 326 posts

Re: SpaceX launches Starship v3 rocket

#261

Post by ls612 »

throwaway85825 wrote: post #250
ls612 wrote: post #193

Earlier quoted context omitted.

The Russians have been trying to use attritable drones for years to break down the Ukrainian IADS and have not yet succeeded. Meanwhile the Israeli F35 fleet with no direct American support was able to crack open Iran’s air defenses at the start of the Twelve Day War with relative ease.

The shahed/geran is just a low cost cruise missile. The f35 comparable is a loyal wingman that does manned/unmanned teaming and carries A/A and A/G.

Such a platform does not exist today in active service in any military (so far as we know).

Re: SpaceX launches Starship v3 rocket

#262

Post by stdatomic »

vessenes wrote: post #239
LandoCalrissian wrote: post #237

12 crashes in 5 years to get 1/5th the capacity of a Saturn V. Good job Elon!

? Starship capacity is 150 (reusable) to 250-300 (non-reusable). Saturn V non-reusable capacity was like 140 metric tons or so. Saturn V cost in today’s dollars roughly $1.5bn per launch. Current Falcon heavy launch from SpaceX is in the $20mm cost (to SX) range, for 64 metric tons. So that’s 1,500:40 = slightly less than 40x cost improvement over Saturn V. Starship’s target costs would be $10mm per reusable launch o…

[flagged]

Re: SpaceX launches Starship v3 rocket

#263

Post by numpad0 »

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…

eliminates the need for ullage thrusters to force the blobby propellants in the tank onto pump intakes

Re: SpaceX launches Starship v3 rocket

#264

Post by XorNot »

throwaway85825 wrote: post #250
ls612 wrote: post #193

Earlier quoted context omitted.

The Russians have been trying to use attritable drones for years to break down the Ukrainian IADS and have not yet succeeded. Meanwhile the Israeli F35 fleet with no direct American support was able to crack open Iran’s air defenses at the start of the Twelve Day War with relative ease.

The shahed/geran is just a low cost cruise missile. The f35 comparable is a loyal wingman that does manned/unmanned teaming and carries A/A and A/G.

Loyal wingman aircraft would have to be stealthy though to do it.

The whole point of the F-35 is that it is a stealthy platform with a very advanced set of targeting and weapons capabilities: but the issue is a similar capability drone would basically have a similar price tag since the expense of the pilot is minor in that case.

Like plausibly the best autonomous F-35 platform would just be an F-35.

Re: SpaceX launches Starship v3 rocket

#265

Post by anonymars »

p-e-w wrote: post #14
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…

But all of those 12 launches happened in just 3 years, and cost a tiny fraction of other major spaceflight development programs. For reference, SLS has been in development for 5 times as long, and cost 15-20 times as much, as Starship, and they still haven’t landed people on the Moon, which has been one of the stated goals since the Constellation program in 2005. I don’t see how the number of failures matters if the…

It seems premature at best to make any sort of triumphant comparison, when Starship has yet to complete an orbit of the Earth while SLS has carried humans to the moon

It's especially ironic to talk about not landing on the moon yet, when it is the landing system--aka Starship!--which is the primary bottleneck for that goal

I am in no way trying to make this some SpaceX vs NASA pissing contest, but there seems to be a tendency to overvalue Starship's promised achievements to SLS's real ones

Re: SpaceX launches Starship v3 rocket

#266

Post by fragmede »

XorNot wrote: post #264
throwaway85825 wrote: post #250

Earlier quoted context omitted.

The shahed/geran is just a low cost cruise missile. The f35 comparable is a loyal wingman that does manned/unmanned teaming and carries A/A and A/G.

Loyal wingman aircraft would have to be stealthy though to do it. The whole point of the F-35 is that it is a stealthy platform with a very advanced set of targeting and weapons capabilities: but the issue is a similar capability drone would basically have a similar price tag since the expense of the pilot is minor in that case. Like plausibly the best autonomous F-35 platform would just be an F-35.

It's not the expense of the pilot but the fact that the human pilot is subject to human biological constraints. Ie they black out after 9 Gs or so. An autonomous platform you'd want to design to be able to routinely do outside that envelope in a way that a platform designed for a human occupant is not.

Re: SpaceX launches Starship v3 rocket

#267

Post by NetMageSCW »

ggreer wrote: post #234
ChuckMcM wrote: post #208

Earlier quoted context omitted.

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?

Rocket engines can’t throttle down very much. Raptor can go down to 40% of its rated thrust, which for V3 would be 100 tons. The ship’s mass is maybe 150 tons with remaining propellant at the start of the landing burn, and probably around 100 tons at the end of the burn. Even at the lowest throttle, three engines would give it a thrust to weight ratio of 2, making hovering impossible and a suicide burn tricky. Two en…

They have a new RCS system on V3 which appeared to be hot gas thrusters. The landing was 3 engines lit to 2 to 1, using the lesson learned in very early flights to have an extra engine in case one fails unexpectedly.

Re: SpaceX launches Starship v3 rocket

#268

Post by NetMageSCW »

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…

First item is wrong - scrub was due to hydraulic pin on launch QD arm not releasing (apparently when released it caused an arm vibration that triggered a re-lock) and they had to improve arm stabilization when pin releases.

Also Ship reached original intended orbit.

A tower catch was never in the plans for this flight.

Re: SpaceX launches Starship v3 rocket

#269

Post by NetMageSCW »

erkt wrote: post #254
GMoromisato wrote: post #96

Earlier quoted context omitted.

Good summary. I was pleasantly surprised that they nailed the re-entry target even after the ascent engine problems. The re-entry itself looks amazingly smooth compared to V2. TBD whether it's good enough for re-usability (much less rapid re-usability). But Flight 12 was definitely forward progress.

It looks like the ships software did a phenomenal job compensating by adding that much longer Second stage burn time. It was also very cool to see the sea levels vector to compensate for the thrust asymmetry. All and all that ship is look really realllllly good. Seems like they just need to add some mass to Raptor to reduce the tendency to tear itself apart..

1 out of 33 failing hardly seems like a tendency - probably some minor issue. Relight was likely an issue with new downcomer that was supposed to improve boost back engine feeds for its flip maneuver - that seems to need work.

Re: SpaceX launches Starship v3 rocket

#270

Post by NetMageSCW »

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…

They’ve already shown they can replace all the tiles in a couple of days with removal and new install. No reason they couldn’t do even faster turn around with just re-install if that was needed.

And human rating is a NASA requirement they won’t have to worry about for a few years.

Post reply on HN