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Starship – SN9 – High-Altitude Flight Test

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Re: Starship – SN9 – High-Altitude Flight Test

#41

Post by _Microft »

rbanffy wrote: post #26
djaychela wrote: post #8

It felt much less eerie as it had commentary this time (and probably because it wasn't the first Starship high-altitude flight), but on the face of it, it looked to be a rougher 'landing' than SN8. I'm sure they got a lot of data from it, but it looked like some of the debris was headed towards SN10 - definitely squeaky bum time then! Can't wait to see this work, though, it really will be a step change for space expl…

Win SN8 at least they had the engine firing itself through the nozzle. This time it seemed the others failed to start. Suicide burns are probably a very bad idea when they have crews and passengers anyway. I assume they'll fire up the landing engines sooner and leave enough time for the vacuum engines to fire as backups if needed.

I think they will practice until they get the landing right all the time.

The engines with vacuum optimized nozzles are not suited for landing. They can not be gimbaled and are very over-expanded as well. I would not be surprised if the engines with vacuum nozzles destroyed themselves if they were fired at sea-level.

Re: Starship – SN9 – High-Altitude Flight Test

#42

Post by jvzr »

_jjkk wrote: post #37
jvzr wrote: post #31

Earlier quoted context omitted.

The catching arm is for the first stage, IIRC Second stage has always been about that flip, be it on the Moon, Mars or Earth

No flipping on the Moon since it provides no advantage there (No aerobraking)

That's a very good point. Looks like my brain also had a major malfunction ;)

Re: Starship – SN9 – High-Altitude Flight Test

#43

Post by samcheng »

dgritsko wrote: post #11
djaychela wrote: post #8

It felt much less eerie as it had commentary this time (and probably because it wasn't the first Starship high-altitude flight), but on the face of it, it looked to be a rougher 'landing' than SN8. I'm sure they got a lot of data from it, but it looked like some of the debris was headed towards SN10 - definitely squeaky bum time then! Can't wait to see this work, though, it really will be a step change for space expl…

Yeah - it really looked like they just got lucky with the debris somehow avoiding SN10. I wonder what the reasoning was behind them even having SN10 on the other pad during this launch - surely it would have been safer to just keep it in a hangar until afterwards?

That opening shot with one spaceship launching while the other was still on the pad was priceless, though... and they are iterating so quickly that much of the value from SN10 was already gained in the manufacturing process.

Re: Starship – SN9 – High-Altitude Flight Test

#44

Post by bostonsre »

le-mark wrote: post #38
cameronh90 wrote: post #35

Earlier quoted context omitted.

What would they replace it with?

Seems like there are two different things here; launching passengers and freight, and returning passengers in comfort and without neck injuries. One could easily envision a passenger only winged glider similar to the space shuttle to serve the passenger return role. Indeed, although spacex has nothing like that planned, these BFRs enable damn near anything.

Maybe some gyroscopic passenger seats that stay in one position relative to the ground so that they only feel g's going in one direction instead of being rag dolls.

Re: Starship – SN9 – High-Altitude Flight Test

#45

Post by dmix »

From wikipedia:

> Three Raptor engines, including SN49. SN9 has had one cryogenic proof test and six static fires. SpaceX attempted to fly SN9 on 28 and 29 of January 2021, but failed to receive permission from the FAA. During landing, one of the engines failed to ignite successfully, causing another hard landing that destroyed SN9.

https://en.wikipedia.org/wiki/SpaceX_Starship?oldformat=true...

This test was slightly shorter than the previous one (6 minutes, 26 seconds vs 6 minutes, 42 seconds) Next launch is expected within February.

Re: Starship – SN9 – High-Altitude Flight Test

#46

Post by Ajedi32 »

cameronh90 wrote: post #35
rbanffy wrote: post #28

Earlier quoted context omitted.

I think the suicide burn will be dropped for passenger flights, but the flip is an integral part of the braking maneuver.

What would they replace it with?

I'd advocate for doing the flip on three engines for the added redundancy, then hovering for a second or so before landing; at least for passenger flights.

Re: Starship – SN9 – High-Altitude Flight Test

#47

Post by msandford »

guardiangod wrote: post #12

Looks like 1 of the engines failed to re-lit during the landing. At least this time 1 of the engines was functioning correctly all the way to the explosion. This is an improvement over SN8 where all the engines failed to re-lit properly.

I'm surprised they aren't trying to light all three and then shutting down whatever doesn't light as needed for the landing burn.

Both of the failed landing have looked like propellant flow problems rather than true engine problems but even so I'd love the chance to get it "right" by getting it "wrong" in that the wrong engines fired up but it didn't hit the ground too hard.

Re: Starship – SN9 – High-Altitude Flight Test

#48

Post by madjam002 »

Ajedi32 wrote: post #39
madjam002 wrote: post #16

Amazing to witness this, although I must say I preferred the camera angles we had in the SN8 stream. Seeing SN8 flip from a distance was great but with SN9 we had to watch it from underneath.

A bit earlier in the stream they tried to show footage from the rocket but the feed kept cutting out. That's probably why they didn't end up showing video of the engines during the landing like last time.

Yeah :( Although even at the start when they had the feed they only switched between them instead of showing both.

IMO Everyday Astronaut has the best video of the landing (https://youtu.be/l4-PwxnJimg?t=16263) - this is similar to what SpaceX had with SN8

Re: Starship – SN9 – High-Altitude Flight Test

#50

Post by unchocked »

rbanffy wrote: post #28
marktangotango wrote: post #22

What I find odd is: when this thing is operational, passengers are supposed to ride through this "flip to land" maneuver?

I think the suicide burn will be dropped for passenger flights, but the flip is an integral part of the braking maneuver.

Starship won't suicide burn. Raptor can downthrottle deeply enough to hover.
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