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Starship's Third Flight Test [video]

spacex.com

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Re: Starship's Third Flight Test [video]

#291

Post by ta1243 »

apendleton wrote: post #92
thelittleone wrote: post #86

Earlier quoted context omitted.

Isn't orbit above 125 miles (200km)?

Orbit is mostly about speed, not about height. Going straight up and down doesn't count, even if you pass the height that some orbital vehicles attain. This vehicle is actually going orbital speed, but not quite orbital height (or rather, it's in an "orbit" that has a very eccentric elliptical shape that would cause it to hit the atmosphere on its way back around; it'd be well above a typical orbital height at apogee…

Technically you can orbit the earth at a pretty low speed. Geostationary satellites orbit about 5,500kph, which is far slower than the 26,000kph starship reached today.

You just need to get high enough, and be pointing in the right direction.

Re: Starship's Third Flight Test [video]

#292

Post by ta1243 »

cubefox wrote: post #264
2OEH8eoCRo0 wrote: post #228

Earlier quoted context omitted.

> Raptor in-space relight demo | No attempt That was a big one to not attempt. Why didn't they attempt it?

Possibly because they partially lost attitude control.

"Starship did not attempt its planned on-orbit relight of a single Raptor engine due to vehicle roll rates during coast"

https://www.spacex.com/launches/mission/?missionId=starship-...

Re: Starship's Third Flight Test [video]

#293

Post by 93po »

bane wrote: post #280
GeoAtreides wrote: post #269

Earlier quoted context omitted.

Jesus Christ, that really puts it into perspective what a game changer starship is

Now do the same calculation in units of hubble space telescope and james webb space telescope masses. Then look at expected reusable launch cost and figure out how many HSTs or JWSTs we could have put in orbit for the same cost.

JWST would also be incredibly less expensive if it didn't have to do the very complex folding required by smaller rockets

Re: Starship's Third Flight Test [video]

#294

Post by mlyle »

dotancohen wrote: post #241
wolf550e wrote: post #192

Earlier quoted context omitted.

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.

An empty Starship has a very low ballistic coefficient, it will be torn apart by the atmosphere if not carefully controlled. Add to that the FTS and there is no real danger to population on the ground.

Columbia was torn apart by the atmosphere... and dropped huge chunks that were a danger to people on the ground-- some as large as a VW Beetle.

Re: Starship's Third Flight Test [video]

#295

Post by euroderf »

namaria wrote: post #97
4ggr0 wrote: post #82

Earlier quoted context omitted.

I actually have the stream open in the background, can't believe how happy and calm this music makes me while patching servers :D

If you like that here's a protip: search for bossa nova instrumentals on youtube for soothing tropical background music

or soma.fm secret agent radio (lots of bossa nova)

Re: Starship's Third Flight Test [video]

#296

Post by lupusreal »

numpad0 wrote: post #248
exDM69 wrote: post #218

Earlier quoted context omitted.

No, that's inefficient and real spacecraft don't do that for typical low earth orbits. Works in Kerbal Space Program, though. Normal orbital insertion is a single burn to orbit (with staging). With the correct initial roll and pitch, the spacecraft follows a perfect gravity turn and ends up in a near circular orbit at main engine cut off.

IIUC real launchers do a single burn to orbit because S2 TWR is not very high and relight is finicky. Launchers that has relightable S2 and/or hypergolic S3 routinely do circularization burns. There are reasons "apogee" is more recognized word than "apoapsis".

> There are reasons "apogee" is more recognized word than "apoapsis".

What are you getting at? The -gee suffix means Earth. Apogee is apoapsis of an orbit around Earth. People playing KSP speak of apoapsis because Kerbin isn't Earth.

Re: Starship's Third Flight Test [video]

#297

Post by namaria »

AnimalMuppet wrote: post #266
namaria wrote: post #99

Earlier quoted context omitted.

I'm still in awe that I got to watch a reentry live stream just now. I wish I could tell my child self what wonders were in store. Watching humanity progress in real time is amazing.

Kids. I got to watch a moon landing live. (Not a stream, and crummy resolution, but still...) [Edit: I meant to be talking smack a bit, but don't let me ruin your enjoyment of the really amazing things that are happening now.]

It's all good, I feel like we're all kids when we wonder about the universe

Re: Starship's Third Flight Test [video]

#298

Post by avmich »

dotancohen wrote: post #239
TMWNN wrote: post #153

Earlier quoted context omitted.

My understanding is that Starship is financially comparable to Falcon 9 on a per-payload basis even if fully expended.

Comparable to Falcon 9? Unlikely - they've got three dozen Raptor engines on that thing, which alone account for the entire cost (not price) of a Falcon 9 flight. Maybe it is comparable to legacy launch providers, such as the Deltas and Atlases. But unlikely comparable to a Falcon 9 launch, even considering the larger payload.

In https://payloadspace.com/starship-report/ the cost of Falcon-9 launch is estimated as $15M. One Raptor is less than $1M, but full Starship has 39 Raptors.

Starship will be much more attractive when it will become fully reusable though.

Re: Starship's Third Flight Test [video]

#299

Post by bdamm »

DarmokJalad1701 wrote: post #267
gorkish wrote: post #222

Earlier quoted context omitted.

Yes this would all be true, if it were true. It is likely to become true at IFT-4 but they are very demonstrably not quite where you say they are. This was still a suborbital flight and they cannot do much of anything that is commercially practical on suborbital flights (like launch satellites, even if they raise their apogee). They appear to have not had good control authority in coast and reentry. They did not do a…

> This was still a suborbital flight and they cannot do much of anything that is commercially practical on suborbital flights If they had flown a slightly steeper ascent and burned for a little longer (possibly a minute if not less), they would have ended in a stable orbit. Not doing that was intentional. They do not need engine relight capability to reach orbit - plenty of orbital rockets exist that cannot relight t…

Yes, but the point was that they can't launch starlinks or just about any commercially meaningful payload until they are reliably in orbit, and they can't reliably get into orbit until they demonstrate at least one relight, because they need to reliably re-enter the atmosphere for the reusability tests.

So they are at least one more launch away from launching starlinks.

Re: Starship's Third Flight Test [video]

#300

Post by aeternum »

johnyzee wrote: post #138
travisgriggs wrote: post #126

Earlier quoted context omitted.

I wouldn’t classify the re-entry survival problem as icing. But otherwise, I agree with you.

Yeah, breaking up in-air during re-entry (at 65 km going by last telemetry) seems like a potential big issue to fix.

Why? Saturn V broke up in-air during re-entry on every "successful" launch as does every ULA rocket.
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