[HN Gopher] Starship - SN9 - High-Altitude Flight Test
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Starship - SN9 - High-Altitude Flight Test
Author : pmhpereira
Score : 98 points
Date : 2021-02-02 20:21 UTC (2 hours ago)
(HTM) web link (www.youtube.com)
(TXT) w3m dump (www.youtube.com)
| reddotX wrote:
| boom
| intrepidhero wrote:
| That's a whole new meaning to halt & catch fire.
| usefulcat wrote:
| In this case, it's more like halt OR catch fire.
| rbanffy wrote:
| The lithobraking maneuver was sub-optimal.
| marktangotango wrote:
| What I find odd is: when this thing is operational, passengers
| are supposed to ride through this "flip to land" maneuver?
| ianai wrote:
| Well apparently they're looking into ways to catch the rocket
| with a landing arm looking platform. Really I think they need
| to get those engines to fire in any circumstance. But with N=2
| it's hard to know anything.
| emilecantin wrote:
| That's for the booster. The goal is to skip landing legs for
| the booster, as it'll only operate around Earth, so it's
| "easy" to build infrastructure instead.
|
| Starship (the 2nd stage) will always do that flip & land on
| legs, as it also needs to do it on Mars.
| jvzr wrote:
| 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
| _jjkk wrote:
| No flipping on the Moon since it provides no advantage
| there (No aerobraking)
| jvzr wrote:
| That's a very good point. Looks like my brain also had a
| major malfunction ;)
| x3n0ph3n3 wrote:
| They sure are!
| rbanffy wrote:
| I think the suicide burn will be dropped for passenger flights,
| but the flip is an integral part of the braking maneuver.
| unchocked wrote:
| Starship won't suicide burn. Raptor can downthrottle deeply
| enough to hover.
| cameronh90 wrote:
| What would they replace it with?
| Ajedi32 wrote:
| 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.
| le-mark wrote:
| 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.
| natch wrote:
| The atmosphere on Mars is not as thick as ours so there
| might be an issue with that winged glider vision. And
| then there is the moon...
| bostonsre wrote:
| 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.
| jlmorton wrote:
| If I've already signed up to ride a large soda can filled with
| 4,600 metric tons of cryogenic methane and oxygen into a near-
| perfect vacuum, only to re-enter the atmosphere at orbital
| velocity, I suppose I could deal with a flip maneuver.
| djaychela wrote:
| 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 exploration.
| dgritsko wrote:
| 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?
| samcheng wrote:
| 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.
| bdamm wrote:
| Their hangars seem to be filling up and I am sure they want
| to make room for SH1 and SN11.
| sbuttgereit wrote:
| As others mentioned, space in rocket build area looks like
| it's to a point where any delay in getting completed test
| articles to test stands, means delaying construction.
|
| There's probably a cost/benefit calculation here, too: SN15
| has been said to be bringing significant design improvements
| over the current design they're flying, and SN10 is of the
| older design. SN11 is probably ready or very close to ready
| for "high-bay" stacking... where SN10 was waiting along with
| the first booster (BN1). SN12, also of the same older design
| is being pro-actively scrapped right now and SN13, SN14 are
| also not going to happen so they get to SN15 faster. They
| have a test article at the launch site (SN7.2) to test a
| different construction material (3mm think stainless steel
| vs. the current 4mm). All that said and done... I'm sure they
| want to get SN10 in the air and would be disappointed by
| losing it... but they already have their sights fixed on the
| future it doesn't completely represent.
| [deleted]
| rbanffy wrote:
| 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.
| _Microft wrote:
| 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.
| ASalazarMX wrote:
| The last seconds looked almost CGI, it's awesome to be witnessing
| this. Wish I was close enough to feel that spaceship BOOM!
| justicezyx wrote:
| Another hidden advancement by SpaceX/Elon, rocket launching now
| is way more normal as a business activity. It used to be rocket
| launch failure is world news worthy; now people feel relaxed
| watching a giant rocket crash into ground and turned into a
| splendid fireball.
|
| This change in perception from the public, is the most critical
| change to fundamentally accelerate the progress of space
| exploration.
| spyspy wrote:
| Seems they're still having problems with their headless tanks
| given it looked like the 2nd raptor landing fire flamed out
| immediately, even earlier than the previous flight. I thought
| they had switched to using COPVs but that either malfunctioned or
| didn't work as well as expected.
| guardiangod wrote:
| 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.
| msandford wrote:
| 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.
| gvb wrote:
| It is interesting and informative to compare SN9 to SN8.
|
| SN8: https://youtu.be/ap-BkkrRg-o?t=6884
|
| SN9: https://youtu.be/_zZ7fIkpBgs?t=704
|
| With SN8, you can clearly see two engines lighting and burning
| properly until just before it (crash) lands.
|
| With SN9, you can clearly see one engine lighting and burning
| properly, but the second engine did not light cleanly and did
| not stay lit.
| CobrastanJorji wrote:
| I've plotted a graph with these two data points and predict
| that it will successfully re-light all three engines in only
| two more tries.
| ben_bai wrote:
| The landing burn will relight 2 engines to slow down, then
| land on 1 engine.
|
| SN8 was really close. Only a couple more seconds before the
| engine ate itself would do. :)
| jsight wrote:
| Uh oh, that means that in two more tries it will be
| relighting too many engines.
| [deleted]
| dmix wrote:
| 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.
| dgritsko wrote:
| I've been so conditioned by how flawless SpaceX launches have
| tended to be over the last few years. It's exciting going back to
| not knowing what will happen during the stream. I'm reminded of
| the enthusiasm around the early Falcon 9 first-stage landing
| tests, when folks were attempting to reconstruct individual
| frames of footage from the first "ocean landings" just to get a
| small taste of what happened. I'm sure they'll nail this landing
| before too long.
| ogre_codes wrote:
| We just have to work on that landing "A little bit".
|
| Understatement of the day.
|
| What's kind of odd is how the video has a weird 80s-90s era sci
| fi feel. All these years I've thought those special effects were
| terrible.
| AnimalMuppet wrote:
| Looked to me like they didn't rotate all the way back to
| vertical, either.
| elihu wrote:
| I think it was the opposite; they rotated past vertical. I'd
| guess they were probably counting on the vectored thrust of a
| second engine to halt the angular momentum.
| AnimalMuppet wrote:
| Sure, could be. I'd like a few seconds earlier on the shot
| that showed the landing pad to be sure.
| madjam002 wrote:
| 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.
| Ajedi32 wrote:
| 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.
| madjam002 wrote:
| 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
| dogma1138 wrote:
| Well they'll stick the landing one day but just not today :(
| BatFastard wrote:
| I was impressed that they confidently landed it right next to
| another prototype. I am sure they will stick the landing next
| time.
| comprambler wrote:
| It is irresponsible and it seems to me that the only reason
| they risked millions of dollars in prototypes is for media
| attention.
|
| Just because it looks cool is not a reason to do it.
| bodhiandphysics wrote:
| The reason to do it is to speed things up. Spacex is willing
| to take risks for speed
| Diederich wrote:
| > Just because it looks cool is not a reason to do it.
|
| I'm pretty certain that 'looks cool' has nothing to do with
| it.
|
| SN10 had to be moved away from the assembly point because
| SN11, SN12, etc are close behind. They needed the space.
|
| Why wasn't SN10 further away? SpaceX is moving fast, and
| moving these building-sized craft around is slow.
|
| SpaceX has a many years of experience in landing rockets.
| Perhaps more directly, they have a lot of experience in
| _failing_ to land rockets. To that end, they 've use a kind
| of 'fail safe' methodology, where for most of the approach,
| the vehicle's trajectory is toward a safe, low-value spot.
|
| For example, during the booster return of the CRS-16 mission
| in 2018, there was a problem, so the booster automatically
| didn't translate back toward its nominal landing pad.
| https://www.youtube.com/watch?v=LFdep0qCmYA In that case, the
| problem ended up not being severe enough to cause a crash.
| NikolaeVarius wrote:
| It looked like something from the engine fell off during the flip
| rafaelturk wrote:
| oh no!
| Diederich wrote:
| And that's why you have an assembly line for Starships:
| https://i.redd.it/dmr9bjhpcee61.jpg (SN9 lacking the RUD symbol
| in that image of course.)
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