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Starship Flight 5: Launch and booster catch [video]

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Re: Starship Flight 5: Launch and booster catch [video]

#661

Post by ceejayoz »

mlindner wrote: post #599
startupsfail wrote: post #584

[flagged]

Burt Rutan, one of the most legendary aerospace engineers of all time used to do regular long presentations to people on why global warming was not man made. Some of them are archived on youtube. And there's many other cases of otherwise smart people having bonkers opinions in areas outside of what they are experts in. If anything, successful people are significantly more likely to do this. It rarely results in their…

See also: https://en.wikipedia.org/wiki/Nobel_disease

“You are a genius!” messes with the brain if heard enough.

Re: Starship Flight 5: Launch and booster catch [video]

#662

Post by mataslauzadis »

3abiton wrote: post #657
dtquad wrote: post #183

Earlier quoted context omitted.

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-…

> MIMO and nonlinear control theories are probably some of the hardest topics in all of engineering. I am curious but clueless about these problems, can you expand more?

Google is a good place to start. https://en.wikibooks.org/wiki/Control_Systems/MIMO_Systems

Re: Starship Flight 5: Launch and booster catch [video]

#663

Post by asadotzler »

robwwilliams wrote: post #420

Awesome achievement. Watched it with my sister at home and brought back memories from the 60s in front of the B&W TV watching some of the early amazing flights and landings. Question for hackers: How does this reorient space programs world-wide? If I were a politician or technocrat in China, Russia, or the EU this would feel like an inverse and intense Sputnik moment — “holy sh—- we have to up our game!”

It doesn't. It makes one or two mega-constellations cheaper for their operators and therefor more profitable, but no one except telecom and sensor platforms really want orbit. It's useless for most things, far worse than working on the planet's surface where all the labor and materials already are.

Re: Starship Flight 5: Launch and booster catch [video]

#665

Post by bagels »

ridgeguy wrote: post #647
supportengineer wrote: post #597

Earlier quoted context omitted.

We could have had this all along.

No. It all depends on cheap computation, reliable/free satellite location systems, and other stuff that weren't things in the (60s, 70s, 80s - pick your own starting point for "all along").

It's as much the economics as it is the technology. It took a ton of private investment, and government investment to get here.

Re: Starship Flight 5: Launch and booster catch [video]

#666

Post by magicalhippo »

martythemaniak wrote: post #605
magicalhippo wrote: post #354

Earlier quoted context omitted.

First off, the booster was going about 1250 km/h when it started its landing burn, it relied purely on drag to get it slowed down to that speed. Going by the telemetry of the seconds before the landing burn and noting the speed vs time, it seems drag was around 40 m/s^2 when it was going at around 3000 km/h. Since drag depends on velocity squared though, it had reduced to just above 10 m/s^2 just before the engines l…

That's excellent work, only nit is I think these were not the v3 raptors. I think they're just now starting production of those, so they still have a bunch of earlier ones they need to use up in these early test flights. This actually makes your calculation more accurate, as earlier versions will need a slightly longer burn time.

Ah, good catch, I must have misread the Wikipedia page. I misread that they were included in the rocket in August. Reading the Raptor page more closely I also see that the 2.75 MN of the Raptor V3 are supposed to be at sea-level.

Anyway, plugging in the Raptor V2 thrust numbers the approximation increases to 4.25 seconds. This is in line with the thrust I used for the V3 being ~8% higher than the V2 thrust figures.

Re: Starship Flight 5: Launch and booster catch [video]

#667

Post by HarHarVeryFunny »

olddog2 wrote: post #589
startupsfail wrote: post #584

[flagged]

If elon can do everything he’s done with an increasingly hostile govt, imagine what he’ll be able to so with a supportive one

Trump is pro big oil, not electric, so Tesla wouldn't be getting any more favors/subsidies under Trump, and with all the NASA money currently flowing to SpaceX, no strings attached, I doubt they would benefit from Trump either. Money coming from Trump will always be conditional on him getting something back.

Re: Starship Flight 5: Launch and booster catch [video]

#668

Post by qaq »

efxhoy wrote: post #641

Strategically this is huge for the US and NATO. Being able to put orders of magnitude more payload in orbit at a fraction of the cost of the competition is a huge advantage in controlling space. Starlink and starshield are already years ahead of what china and russia has, starship is going to widen that gap even further.

Well if US would deploy global kinetic bombardment system that would def. be a game changer.

Re: Starship Flight 5: Launch and booster catch [video]

#669

Post by Anon1096 »

roca wrote: post #611
FrustratedMonky wrote: post #598

Earlier quoted context omitted.

[flagged]

Both. A single person can be great in some areas and a malicious loon in others. In fact, great success in one field can provide the self-confidence and capital to be a catastrophe in others. But also keep in mind that Musk isn't personally designing and building everything SpaceX does. The staff at SpaceX deserve more credit than they get, especially Gwynne Shotwell.

It's become an absolute meme on the left-leaning internet to say SpaceX isn't Elon and Shotwell is doing all the work. You can't go to a thread on this site or reddit etc without it being brought up.

Really I am pretty sure it is just coping to deal with the uncomfortable fact that Elon (bad guy) is doing something great and clearly is skilled. Ask anyone at SpaceX or Shotwell herself and they will all say Elon is very important to its success.

Re: Starship Flight 5: Launch and booster catch [video]

#670

Post by bagels »

cpeterso wrote: post #654
ChuckMcM wrote: post #516

Pretty 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…

What’s the advantage of catching the booster over landing it in the ground? Catching it seems like an extra complication.

You save the mass of the landing systems, you get to have all that mass on the ground and not have to lift it into space. Dramatically improves the performance of the rocket.
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