Starship's Third Flight Test [video] • Hacker News Board

Re: Starship's Third Flight Test [video]

#191

Post by grecy » Thu, Mar 14, 2024, 3:11 PM UTC

BenoitP wrote: post #136

FR24 shows a Dassault Falcon 900EX doing circles around the expected Starship re-entry location (Perth to Perth flight plan): https://www.flightradar24.com/MXJ/345b8f09

From a safety perspective, how does that work?

This is obviously a test, and safe to say the vehicle was out of control and not entirely predictable. I realize they wouldn't fly into the actual predicted landing area, but just being close must be a risk.

Would the flight crew on that plane literally be scanning the sky above them to make sure they're not in the direct path of whatever comes down at whatever speed?

Re: Starship's Third Flight Test [video]

#192

Post by wolf550e » Thu, Mar 14, 2024, 3:14 PM UTC

DarmokJalad1701 wrote: post #167

Laremere wrote: post #148

Earlier quoted context omitted.

Parent's (correct) point is that it isn't a matter of the ascent trajectory. They can't leave the Starship up in orbit, and where it reenters needs to be controlled.

> They can't leave the Starship up in orbit, and where it reenters needs to be controlled. Why? Plenty of boosters re-enter uncontrolled and burn up all the time.

Starship is huge and heavy and made of steel, it will not burn up on reentry, if it falls on a populated area it will kill people. They will not be allowed orbital trajectories until they demonstrate they can control the deorbit burn.

Re: Starship's Third Flight Test [video]

#193

Post by Etheryte » Thu, Mar 14, 2024, 3:14 PM UTC

sneak wrote: post #67

_Microft wrote: post #58

Earlier quoted context omitted.

I guess they didn’t want to make it too easy for some Chinese fishing vessels ;)

Chinese fishing vessels in the Gulf of Mexico?

Illegal fishing by Chinese fleets is now commonplace in Africa, in Argentina, etc [0], so given how much they've expanded operations over the years it's only a matter of time before you see them there too, if it hasn't happened already.

[0] https://www.nytimes.com/interactive/2022/09/26/world/asia/ch...

Re: Starship's Third Flight Test [video]

#194

Post by Daneel_ » Thu, Mar 14, 2024, 3:14 PM UTC

hughes wrote: post #133

XorNot wrote: post #112

Earlier quoted context omitted.

Its still an issue because they haven't really confidently demonstrated a relight of the engines while flying. Hot staging avoids a relight, but they still need to do it. It does mean they technically have an expendable heavy launch vehicle though.

The boostback burn demonstrated relight today.

The key demonstration is “relight in a vacuum”, which was the test that was skipped late in the stream. If you can do this then deorbiting is possible. Relight of the booster doesn’t demonstrate this, unfortunately.

Re: Starship's Third Flight Test [video]

#195

Post by terramex » Thu, Mar 14, 2024, 3:18 PM UTC

grecy wrote: post #191

BenoitP wrote: post #136

FR24 shows a Dassault Falcon 900EX doing circles around the expected Starship re-entry location (Perth to Perth flight plan): https://www.flightradar24.com/MXJ/345b8f09

From a safety perspective, how does that work? This is obviously a test, and safe to say the vehicle was out of control and not entirely predictable. I realize they wouldn't fly into the actual predicted landing area, but just being close must be a risk. Would the flight crew on that plane literally be scanning the sky above them to make sure they're not in the direct path of whatever comes down at whatever speed?

If onboard computer would sense that Ship is going somewhere it should not be it would trigger FTS (Flight Termination System) and destroy it with debris falling into Atlantic Ocean (exclusion zone was there as well).

Once Ship finished burn it simply had to land in predicted landing area in Indian Ocean, it did not have enough fuel on board to significantly change trajectory even if computer went crazy.

Re: Starship's Third Flight Test [video]

#196

Post by neffo » Thu, Mar 14, 2024, 3:19 PM UTC

golol wrote: post #184

DarmokJalad1701 wrote: post #80

The test is essentially a success at this point. Starship can take payload to orbit and open/close the payload doors. The remaining things are icing on the cake. They can refine re-usability while flying payloads.

One technical modification: They need engine relight in orbit to work to deliver payloads, otherwise Starship will stay in orbit and they can not test reentry.

You need a second burn just to enter orbit. You burn at the top of the sub-orbital arc (opposite side of the earth) to enter orbit.

Re: Starship's Third Flight Test [video]

#197

Post by baq » Thu, Mar 14, 2024, 3:20 PM UTC

Laremere wrote: post #172

DarmokJalad1701 wrote: post #151

Earlier quoted context omitted.

They can launch payloads that bring in revenue while working on that problem. There is a good chance they put a bunch of Starlinks on the next flight.

They might do one to test deployment, but it'd be a throwaway. Their relight test was skipped (not said why), so they still don't have confirmation they can control where Starship re-eneters. Until that happens, it's very unlikely they'll target actual orbital velocity. The Starlink satellites do have thrusters, but they're ion engines, so not nearly enough thrust to get that last bit into orbit before they'd re-ente…

99% chance that they lost attitude control hence couldn't point the business end towards wherever they wanted to. we know they can relight the engine on the booster and we know they can relight for landing burns.

no surprise if the next launch has a couple pre-production big starlink birds.

Re: Starship's Third Flight Test [video]

#198

Post by Kon-Peki » Thu, Mar 14, 2024, 3:21 PM UTC

b112 wrote: post #115

jajko wrote: post #105

Earlier quoted context omitted.

On shores of Africa, in Gulf of Mexico... yes, in 2024 ships can travel far

Probably even in Lake Superior.

I was going to write that a boat could get from the ocean into Lake Superior without ever entering the United States (by hugging the Canadian side of all lakes and rivers), but it appears that there is a dam on the St Lawrence River near Cornwall Ontario that forces you to take a short <10 mile detour through a river/canal in New York.

Re: Starship's Third Flight Test [video]

#199

Post by perihelions » Thu, Mar 14, 2024, 3:21 PM UTC

dotnet00 wrote: post #185

perihelions wrote: post #159

Earlier quoted context omitted.

I don't believe that's the case—see the math in my sibling comment.

The number going around from people who typically do this kind of thing is a ~55x235km orbit: https://twitter.com/planet4589/status/1768270310199935299 I'm not really in a place to judge your math right now to really add anything on that.

Yeah, that guy's absolutely a domain expert! But note that he writes -55 km, not +55 km—that is a suborbital trajectory. Its perigee is below the earth's surface; -55 km is a negative altitude.

(He's also clearly using a different set of data than I have access to. I can't read the context of the Twitter thread so I don't know what numbers he's looking at).

Re: Starship's Third Flight Test [video]

#200

Post by b112 » Thu, Mar 14, 2024, 3:22 PM UTC

fallingknife wrote: post #128

b112 wrote: post #111

Earlier quoted context omitted.

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