[HN Gopher] Crew Dragon launch escape demonstration
___________________________________________________________________
Crew Dragon launch escape demonstration
Author : eps
Score : 455 points
Date : 2020-01-19 15:15 UTC (7 hours ago)
(HTM) web link (www.spacex.com)
(TXT) w3m dump (www.spacex.com)
| irjustin wrote:
| Congratulations to the SpaceX and the whole team! That moment of
| truth when the thrust was lost and the module separated was
| actually way faster than I had expected. I could barely notice
| the exhaust plume was smaller and the dragon had already left.
|
| I think it's incredibly satisfying to note that SpaceX is so good
| at the launch sequence with the Falcon 9 that there were zero
| delays except weather. With any new rocket system test, I
| completely expect there to be multiple delays with the countdown.
|
| Again, congrats to everyone and their hard work.
| 51Cards wrote:
| I was also amazed by this until I watched the post press
| conference. Elon seemed to describe in an answer to Everyday
| Astronaut that the launch abort sequence was set to trigger at
| a specific speed/altitude and that it was the abort program
| that told the engines to shut down. I would like to see that
| clarified further but I watched that segment twice and it seems
| that the abort system was in control, and step 1 was shut down
| the main engine, step 2 - pressurize/start the abort engines,
| and so on.
| irjustin wrote:
| That also could mean, while the abort system said "shut
| down", the thing that said "get away" was not directly
| connected, but still using sensor/telemetry inputs as the
| decision maker.
|
| Also, I'm really interested in knowing if the fireball was
| performed by the automated abort system.
|
| I would love these to be the answer, so looking forward to
| clarification.
| vibrolax wrote:
| 1) the Dragon initiated the F5 booster shutdown when its
| sensors detected that it had reached the pre-programmed
| abort velocity 2) the Dragon initiated the escape according
| to the abort sequence, not by ground command 3) the
| fireball was initiated by structural failure as the F5
| broke up due to aerodynamic forces, not by the range safety
| destruct. 4) All of these abort sequence actions were
| explained in SpaceX's live stream.
| JshWright wrote:
| F[alcon]5 was a concept that never made it past very
| early designs. The rocket SpaceX flies is the Falcon9.
| LeonM wrote:
| I think he is referring to the 'block 5' Falcon, i.e. the
| current iteration in the development cycle of the Falcon
| 9.
| JshWright wrote:
| Perhaps (I'm a pretty avid SpaceX enthusiast, and I've
| never heard that abbreviation before)
| krisoft wrote:
| Minor nitpick about point 3. John Insprucker said around
| 13:40 in the stream: "our simulation show that the Falcon
| will likely break apart due to the tumbling, instead of
| having the destruct system triggered and destroying the
| rocket." So what you wrote at point 3 is only likely, but
| not certain. (Unless of course you know from some source,
| that they have confirmed the sequence of events since.)
| JshWright wrote:
| The upper stage (which is wired to the same FTS) hit the
| ocean intact.
| brianwawok wrote:
| Well point 3 means it didn't have a blow up at time Y
| feature. If there was no plan to blow it up and
| simulations said it would likely blow up, isn't a pretty
| safe conclusion that predicated explosion happened?
| 51Cards wrote:
| That is my question too, if the abort system just went
| "Step 1, Step 2, etc." or if the abort system went "Step 1"
| and the automated processes took over from there. It wasn't
| entirely clear but it felt like the first one which is why
| I watched it again.
|
| As for the fireball, from the press conference I got the
| sense that the fireball was not triggered manually, that
| the rocket just broke up.
|
| Again, on neither I'm 100% sure.
| shmerl wrote:
| Great result. One thing stood out, in the commentary they
| sometimes used feet and sometimes meters. Better just to stick to
| metric to avoid the mess. Reminds me various stories, when mix up
| between metric and imperial made space missions fail. So SpaceX
| teams should have stronger focus on avoiding this.
| JshWright wrote:
| I think you're confusing the public broadcast commentary with
| the engineering that goes into the actual hardware. There are
| slightly different levels of rigor involved... (and very
| different audiences)
| shmerl wrote:
| I think it should be uniform, until it becomes a habit.
| Making it lax in one area can backfire in another.
|
| That's besides the point that someone should be advancing the
| usage of metric for the general public, and who is best
| suited for it, if not someone already invested in it like
| SpaceX. Their HUD in the video is already using metric for
| example.
| JshWright wrote:
| Bear in mind that the audience of the webcast is not
| uniformly comfortable with metric units. Using both makes
| sure that everyone has a sense of the scales involved.
|
| By using them both, it's a good way to give someone who
| doesn't use metric a basic understanding of the
| conversions.
| shmerl wrote:
| That's the point. In order to make the public
| comfortable, metric should be used for them. That's the
| only way to gain comfort. Not using it only prolongs the
| issue.
|
| The government basically gave up on it, leaving
| metrication in shambles. So SpaceX is in good position to
| do something about it.
|
| And using one or another intermittently only adds
| confusion IMHO, unless you literally use both for each
| value which is even more annoying (at least to me).
| JshWright wrote:
| It's cool that you're so passionate about this, but bear
| in mind your intitial comment was suggesting that SpaceX
| was risking a mission failure by mixing units in a
| broadcast intended for public consumption.
|
| The goalposts seem to have drifted a bit here...
| shmerl wrote:
| It's both. Presenting to the public and being consistent.
| If they are training their own teams to be used to it, it
| should be consistent everywhere. And public will benefit
| from it, like above.
| thisisastopsign wrote:
| Congrats SpaceX team! I hope they post the view from the Crew
| Dragon vehicle of the Falcon 9 breaking up. That seems to be the
| one view that was missed (in addition to splashdown from the
| aircraft angle)
| pier25 wrote:
| History in the making.
| remote_phone wrote:
| I watched the Chris Hadfield Masterclass on being an astronaut.
| It is wonderful and he is a fantastic speaker and lecturer. He
| talked about the actual launch, how nothing is left for chance,
| and how every second is accounted for. The astronauts need to
| fight the effects of the incredible acceleration and have a plan
| for literally every second until they reach space on 7-8 mins.
| The MasterClass itself is great, totally worth it and Chris
| Hadfield is a delight.
| lhoff wrote:
| Podcast recommendation for all german speakers here. Tim Pritlove
| recently interviewed Hans Koenigsmann (Engineer and Vice
| President of Mission Assurance at SpaceX since 2011). The episode
| was released two days ago. They talk about the history of Space X
| and the future planes (Mars mission and Starlink). Its part of
| the Podcast "Raumzeit".
|
| https://raumzeit-podcast.de/2020/01/17/rz083-spacex/
| _Microft wrote:
| Very worthwhile if one is interested in rockets and SpaceX in
| particular. The interview was summarized in English on the
| SpaceX subreddit.
|
| https://old.reddit.com/r/spacex/comments/epzayc/german_raumz...
| hi41 wrote:
| My jaw drops every time I hear about SpaceX and Tesla. How could
| Elon grasp two extremely different and difficult technologies and
| build such amazing companies within a decade. I have difficulty
| learning new things. Some pointers will help. Thank you.
| sfblah wrote:
| You, my good sir, are a fanboi's fanboy.
| toomuchtodo wrote:
| It amazes me how this forum handles praise for determination,
| passion, and perseverance.
|
| We shouldn't discount luck, but you can respect the traits
| above without the derogatory terms ("fan boi").
| whateveracct wrote:
| Idolization of others is unbecoming period. No person is
| special or mystically above others for doing acts of
| business and technology. That's what I live by at least.
| egdod wrote:
| We're all deserving of respect as humans. But some people
| really are better at things than other people. It's not
| unbecoming to acknowledge that.
| endorphone wrote:
| Admiring the accomplishments of others is unbecoming?
| That is remarkably sad.
|
| As the root post says, it is _amazing_ what Musk has
| achieved, and I 'd love to learn what the secret is. I
| suspect it's that he knows the limits of his own
| capabilities so he finds the right people to execute his
| visions. But it is absolutely remarkable that a payment
| startup guy kicked off two envelope-pushing companies
| that have achieved such heights.
|
| Countless rich guys have taken their lucre and tried to
| change the world, usually to extraordinary failure. Tesla
| and SpaceX have both changed the world and entire
| industries (as did PayPal), and they're just getting
| started.
| whateveracct wrote:
| Sorry but nobody is remarkable in my eyes no matter how
| hard they try
| zionic wrote:
| That seems like a very toxic and unhealthy mindset. If I
| had to guess, seemingly an internal defense mechanism
| stemming from one's own insecurities.
| whateveracct wrote:
| I don't see anything unhealthy about it. The mindset sees
| people as people. Nobody is especially special and
| everyone is simply Themself. Ever seeing others as More
| Impressive somehow is what is toxic.
|
| You seem to imply that I am insecure about my lack of
| success or skill in relation to others? And that I wish
| to bring others down to defend against this insecurity?
|
| Fundamental misunderstanding - we speak different
| languages and hold different values. I never compare
| myself to others and am very happy with my life and the
| way I'm going about it.
|
| And if someone regarded me in this way, I would reject it
| and tell them to cut it out.
| [deleted]
| soheil wrote:
| I think it would be odd if there did not exist a person or two
| at the extreme fringes of the gaussian distribution of one's
| achievements. The real question is are there more incredible
| people even further out on the distribution tail that somehow
| are not so visible to the public.
| nojvek wrote:
| He made his billion from PayPal (software) and really went
| serious to make a dent in hardware.
|
| I really wish more billionaires, govts and VCs poured money
| into serious hardware and manufacturing.
|
| It really seems like US has lost its edge in manufacturing. 90%
| of the things in the mall/online seem to be from China.
|
| The economy may be doing great today but really not a great
| sign of the future.
| mft_ wrote:
| According to Wikipedia, he made $165m from the sale of
| PayPal.
| okareaman wrote:
| How To Think Like Elon Musk
| https://www.youtube.com/watch?v=yXe8JGB4FWA
| caconym_ wrote:
| Yeah, the guy is an absolute maniac and based on what I've
| heard I would not want to work at either of those companies,
| but you can't argue with his success. He's broken into two
| mature markets that have been dominated by massive incumbents
| for half a century or more. How many business leaders can say
| the same?
| jariel wrote:
| "How could Elon grasp two extremely different and difficult
| technologies and build such amazing companies within a decade."
|
| Because they're both very well established technologies and
| there are tons of people with deep expertise in this area.
|
| Space is full of kafkaesque levels of bureaucracy, it's
| shocking that we haven't been doing this for a long time.
|
| It's the scale of these industries that he's taking on that is
| mind-boggling, not really the tech itself. It's operational
| exceptionalism more than anything.
| code4tee wrote:
| Looks like a total success. Great job.
| Tepix wrote:
| It looks good so far but we won't really know until the
| telemetry has been looked at. For example the g-forces on the
| astronauts could have exceeded the safe limits.
| rrmm wrote:
| I believe the recovery teams have to meet the proper
| deadlines as well.
| Already__Taken wrote:
| The webcast said the US air force normally gets the crew,
| did I miss-hear?
| rrmm wrote:
| That might be the case. I was assuming based on some
| comments I vaguely recall following the DM-1 capsule
| recovery.
|
| EDIT: https://spaceflightnow.com/2020/01/16/spacex-abort-
| test-serv... has more details about the recovery
| operations and the Air Force's role.
| vermontdevil wrote:
| During press conference, they said the highest the g forces
| hit was 3.5
| skunkworker wrote:
| Isn't that similar to a roller coaster?
| wbl wrote:
| You also have to worry about jerk and orientation.
| milansuk wrote:
| I hope, this is the last time when we see the abort/escape system
| activated. Good luck and godspeed, Spacex!
| rohan1024 wrote:
| That was great!
|
| The guys said at the beginning that they are expecting Falcon to
| blow up because aerodynamics change significantly once the nose
| separates.
|
| Stupid question, couldn't they just give Falcon it's own nose so
| that it doesn't blow up after dragon separates? Dragon could have
| been mounted on that nose.
| peterburkimsher wrote:
| I think one of the purposes of the test was to ensure that the
| crew can escape safely from a dramatic fireball. It's hard to
| simulate throwing shrapnel and fuel at the Dragon capsule
| without actually blowing up the booster.
|
| However, the Falcon wasn't intentionally detonated! This was
| also by design; if explosive charges were placed down the side
| and made it come apart naturally, it would come apart in a
| predictable way. If you know anything about test-driven
| development, someone would try to made assumptions about the
| explosion. By allowing an uncontrolled explosion at the time
| when the Falcon is experiencing the most extreme aerodynamic
| forces, it's basically creating a worst-case scenario.
|
| SpaceX successfully proved that the Dragon capsule can escape
| from that worst-case, and that's great news. It'll be flying
| with crew very soon, I think.
| Ndymium wrote:
| I would imagine the escape system is only used when there is
| something very wrong with the flight. In that case there is
| usually no hope of recovering the rocket anyway (if it didn't
| explode, could it make it to the landing site?). The added
| weight and complexity probably make this a bad trade-off.
| nrb wrote:
| In the event an in-flight abort becomes necessary, odds are
| that the craft is probably going to be lost no matter what.
| Adding additional complexity or weight for a vanishingly
| unlikely scenario likely isn't worth it to them.
| LeonM wrote:
| > Stupid question, couldn't they just give Falcon it's own nose
| so that it doesn't blow up after dragon separates? Dragon could
| have been mounted on that nose.
|
| There are no stupid questions.
|
| The abort system is only there as a last resort in case of
| booster failure. So in a situation where the abort system is
| fired, the falcon has probably already failed beyond the point
| where it is expected to be able to land.
| 51Cards wrote:
| There is a great thread on r/spacex discussing the logistics
| around trying to save the booster. In the end it was generally
| agreed not to be possible.
|
| A VERY brief summary of reasons from memory: deceleration
| causes fuel to rise up in the tanks likely rupturing them from
| hydralic impact alone, lack of thrust even momentarily causes
| the rocket to become unstable end to end, only 3 engines are
| equipped to be relightable and may not relight because the fuel
| would be at the top of the tanks, too much fuel mass to burn
| off before landing, too much mass with second stage, etc.
|
| Elon tweeted out the same, that they played with it and deemed
| it not possible. As such I beleive the rocket was stripped of
| landing legs and grid fins too. Was a one way ride only.
| jtms wrote:
| I'm guessing since this test was not focused on the rocket
| itself that they just decided it wasn't a problem worth
| trying to solve simultaneously with the dragon
| Tuna-Fish wrote:
| It's a problem that does not need to be solved. If all goes
| well, this was the very last time the launch abort system
| is ever fired. It's an emergency escape system for when
| things have already gone pear-shaped, and in most cases
| would only be triggered _after_ the rocket below it has
| failed in some way.
| rrmm wrote:
| The post-test press conference is starting on nasa tv for those
| interested (11:50EST).
| _Microft wrote:
| There will be a press conference at 11:30 AM (ET) on
| https://www.nasa.gov/nasalive by the way.
|
| One thing that is clear is that the phrase of _launching American
| astronauts on American rockets from American soil_ will be used.
| Multiple times. That 's as sure as SpaceX livestream hosts using
| the formulation _' Historic' Launch Complex 39A_ ;)
| rrmm wrote:
| All smiles at the press conference, so seems like things went
| well.
|
| Elon says, Hardware for first launch will be ready end of Feb,
| but lots of double checks have to happen before launch and
| schedules lined up for ISS. Expect launch to happen in 2Q.
|
| Elon adds that they need to get the space craftback and check
| it over to make sure all is well and there is nothing to
| address.
|
| Elon teases trying to catch the dragon on re-entry to remove
| some of the constraints a splash down imposes.
| [deleted]
| growlist wrote:
| I love this idea - caught gently with the ship immediately
| turning back for home, like something out of James Bond.
| ericcumbee wrote:
| I've noticed its only "Historic" Launch Complex 39A, when
| SpaceX is doing something that could be considered "Historic",
| for every day SpaceX Launches they seem to revert back to it
| just being "Launch Complex 39A"
| callesgg wrote:
| History is in the past the present will be history in the
| future.
| ianai wrote:
| Anybody suspect this impacts Tesla stock? Not that it should, but
| as a herd reaction.
| greglindahl wrote:
| My herd reaction is that I am distressed to see this kind of
| thread in a SpaceX discussion.
| ianai wrote:
| We're here to discuss the latest Musk-backed company's
| achievement. There's a huge interest in all things Musk. To
| the point that everything he does seems widely related - I
| mean how many people here are rooting for his dream of a Mars
| colony? So I asked whether it could affect another Musk
| company. It's related.
| derrikcurran wrote:
| Why? Investment in Tesla is probably good for SpaceX in the
| long term.
| saberdancer wrote:
| Was there mention of why they did not do a launch escape while
| the F5 was at full throttle? I understand this reduces the risk
| and was probably deemed to be good enough of a test, but I was
| expecting the test to be "worst case scenario" or in other words,
| F5 on full power at MaxQ.
| Taniwha wrote:
| I think that "F5 on full power at MaxQ" is not a worst case
| scenario, it's more like "flying nominally" - doing it at maxQ
| is certainly the thing to do - but "on FS flameout" is more
| realistic
| gpm wrote:
| The Falcon 9 never goes through MaxQ at full throttle,
| throttling down before MaxQ and up after MaxQ is part of the
| normal flight path. This Falcon 9 followed the normal flight
| path right up to the point where the abort was artificially
| induced.
|
| I believe the abort did actually take place at full throttle
| though, it happened at the point of max drag which occurs
| shortly after Max Q, and is after the rocket has throttled back
| up. The intent was definitely to trigger the abort at the worst
| time during the normal flight path.
| foota wrote:
| Wouldn't it be good to test whether the abort works in the
| face of an unexpected flight path, which could potentially be
| more stressful?
|
| Although there's probably not much of a difference if they
| full throttled shortly after MaxQ and then aborted.
| brianwawok wrote:
| This test seems more useful? Why put it through a path that
| can't happen? If throttle is out of control and randomly
| going, that's a good case to trigger an abort right then.
| growlist wrote:
| Being able to watch regular (SpaceX) rocket launches live -
| including deployment of satellites in orbit and landing of
| boosters - free, for entertainment purposes, is in my opinion one
| of the most amazing things going at present. As a demonstration
| of how far technology has progressed to make this all possible it
| blows my mind.
| chrisco255 wrote:
| Yeah it's a good point, network television limited the amount
| of airtime things like this could get in prior decades.
| sandworm101 wrote:
| >> - free, for entertainment purposes, is in my opinion one of
| the most amazing things going at present.
|
| Except that it isn't. All that classic NASA space footage was
| shared because it was copyright-free. As products of the US
| federal government they were not subject to copyright
| protection. They were transmitted and used everywhere. When
| "The Six Million Dollar Man" or "Buck Rogers" wanted to use
| NASA launch footage (or USAF crash footage) they just did. No
| questions asked.
|
| SpaceX footage isn't from the US fed. It is private and
| therefore protected copyright. It cannot be used anywhere
| anytime. We all must ask SpaceX for permission. Use it in a
| manner that SpaceX disagrees with and you can expect lawyers.
| You wont see the failure footage from SpaceX ever used as nasa
| footage was used by countless scifi productions.
|
| So no, this is no amazing thing. While modern footage is a
| visual feast, in terms of freedom it is a step down from what
| we once had. I think those running TV news networks (or
| youtube, or any other distribution network) would rather return
| to the old system whereby they could use footage however they
| liked. We won't ever see SpaceX crash footage used for much of
| anything.
|
| What I am talking about. Six Million Dollar Man opening:
| https://www.youtube.com/watch?v=bGO57y4td-c
|
| Original NASA footage: (Crash at about 2:00)
| https://www.youtube.com/watch?v=50dDWT48b9M
| optimiz3 wrote:
| > But SpaceX footage isn't from the US fed. It is subject to
| copyright. It cannot be used anywhere anytime. We all must
| ask SpaceX for permission. Use it in a manner that SpaceX
| disagrees with and you can expect lawyers.
|
| So much pessimism. I think it's great a private for profit
| corporation is doing as much as it is given it has no
| obligation to do so.
| sandworm101 wrote:
| >> as it is given it has no obligation to do so.
|
| That's the big change, the lack of obligation. If SpaceX is
| going to be fulfilling government contracts, on government
| facilities/ranges, using countless government employees,
| resulting footage should be free.
|
| It hasn't happened yet, but with human spaceflight nearing
| we may see SpaceX drafting license deals in a manner NASA
| never contemplated.
| MoronInAHurry wrote:
| SpaceX recently relicensed their photos to an
| Attribution-NonCommercial license, when previously they
| were effectively public domain under Creative Commons
| Zero: https://www.vice.com/en_us/article/88449p/spacex-
| just-retroa...
| sandworm101 wrote:
| Yup. The last thing SpaceX wants is to see somebody else
| make a buck from their footage. We have seen NASA logos
| in a thousand scifi productions. We will never see the
| SpaceX logo used in such a manner.
| mattr47 wrote:
| Your posts show an obvious bias against spaceX. Why the
| hate?
| sandworm101 wrote:
| Bias? Im critical of the US government's intellectual
| property policy in relation to spacex contracts and speak
| to nothing else. If that constitutes some sort of bias
| then unbiased criticism is impossible.
|
| Id be critical of any privatization of something that was
| once public domain, specifically spacelaunch footage.
| mrtnmcc wrote:
| Is that pure speculation? SpaceX isn't protesting the
| countless YouTube videos and derivative works from their
| launches.
| zlsa wrote:
| Are you expecting SpaceX to allow their (copyrighted)
| logo to appear in various media without requesting
| permission first?
|
| NASA's copyright policy is the exception, not the rule.
| djsumdog wrote:
| Huh. Is there a record of which photos were originally
| CC0? If you've already downloaded them as CC0, and they
| were once licensed as such, you can't just take it back.
| It's like releasing into the wile with GPLv3. You can re-
| license it if all the authors agree, but the original
| code at the point of re-license, if you have a copy, can
| never lose its GPLv3 status.
| dylan604 wrote:
| I think if you are receiving public/govt/fed money to do
| your mission(s), then the footage should also abide by the
| non-copyrightable footage as well.
| dahfizz wrote:
| Why? NASA partners with SpaceX and other space companies
| on specific projects. For example, NASA needed a special
| crew module and so they commissioned SpaceX to design and
| build the crew dragon.
|
| I don't see why having NASA as a customer means SpaceX
| loses the right to private property.
|
| If a government agency decided to become a paying
| customer of your SaaS project, should you be forced to
| open source all your code because you are now receiving
| public money? I suspect the answer is the same as with
| the SpaceX footage - the public may benefit if it was
| released, but it seems an unreasonable burden.
| dylan604 wrote:
| Simple, because it's my money that paid for it. That's
| the reason NASA footage is public domain. It's publicly
| funded with tax dollars.
| dahfizz wrote:
| SpaceX is not 100% NASA funded. NASA contracts SpaceX for
| a specific product and nasa receives that product. In
| other words, you do get what you pay for.
|
| Do you believe that any software the government buys must
| be open sourced? Your tax dollars buy plenty of iPhones
| and Macs. Should apple release all their software and
| hardware to you?
| dylan604 wrote:
| I think you are reading too much into my original
| statement. I did NOT say I think 100% of all SpaceX
| footage should be made public domain. I specifically
| stated that if it is funded by govt funding, then it
| should.
| albntomat0 wrote:
| SpaceX deliveries what they are contracted as a private
| company to provide. To my knowledge, this does not
| include putting mission footage into the public domain.
| Adding additional requirements increases the cost passed
| on to the tax payer.
| johnghanks wrote:
| Classic HN. Finding a way to spin something great into
| something negative.
| shadowgovt wrote:
| "Free as in advertising," not "free as in speech."
| tomphoolery wrote:
| > I think those running TV news networks would rather return
| to the old system whereby they could show the footage
| whatever and whenever.
|
| I don't think the opinion of "those running TV news networks"
| really matters all that much when we're talking about space.
| rcw4256 wrote:
| > Use it in a manner that SpaceX disagrees with and you can
| expect lawyers.
|
| This is probably true, but it's hard to be certain that
| they'd prevail. Has this actually been tested in court?
| nexuist wrote:
| >Use it in a manner that SpaceX disagrees with and you can
| expect lawyers. You wont see the failure footage from SpaceX
| ever used as nasa footage was used by countless scifi
| productions.
|
| SpaceX literally uploaded a video of all their crashes
| spliced together in a comedic montage. It's called How Not to
| Land an Orbital Rocket Booster.
|
| https://youtu.be/bvim4rsNHkQ
|
| Even crash footage is good PR for them. There are still
| millions of Americans who do not know what SpaceX is or what
| it does.
| xingyzt wrote:
| The crash compilation is public [1] because they were tests
| with minimal customer risks involved. You wouldn't find
| footage of CRS-7, with its dozens of NASA payloads,
| disintegrating on any of SpaceX's official media channels.
|
| [1] But not public domain. It's still copyrighted.
| hartator wrote:
| You mean this?
| https://www.youtube.com/watch?v=OAX7UFd70M8
| yreg wrote:
| >We won't ever see SpaceX crash footage used for much of
| anything.
|
| We will if SpaceX allows it. How can you be sure they won't?
| anoncake wrote:
| We can't be sure they will, that's the problem.
| jtms wrote:
| Gadflies everywhere
| [deleted]
| paulmendoza wrote:
| I think he just means he likes watching rockets launch.
| Dylan16807 wrote:
| The quote says right there "for entertainment purposes".
| Stock footage is not that. And come on, being able to use
| NASA footage in your own works is one of the least exciting
| parts about space travel.
| soheil wrote:
| The explosion was unexpected so either they will have to fix what
| went wrong there, which in turn will possibly effect the design
| which would then most likely need another flight test if you want
| to be safe enough or they will let it be as is which would be
| unsafe?
|
| They expected the splashdown to happen several seconds later than
| it did. This could mean the capsule was going faster than it
| should have before its parachute deploy or it didn't slow down
| enough when hitting the water which would be worse.
|
| Finally the main parachutes where touching each other pretty
| aggressively it wouldn't seem than unfathomable that two or more
| of them get tangled up, I don't think there is a backup solution
| for if that happens.
| whoisthemachine wrote:
| > They expected the splashdown to happen several seconds later
| than it did. This could mean the capsule was going faster than
| it should have before its parachute deploy or it didn't slow
| down enough when hitting the water which would be worse.
|
| While you can control for variables greatly when you're flying
| under an engine, I'd imagine it's not so easy to control for
| environmental variables (such as local variations in wind
| speed) when you're landing under parachutes. It probably would
| have been safer for the broadcasters to have had an estimated
| time of landing with a +/- 20 or so seconds on the display, but
| I personally doubt landing a little sooner than expected will
| be a major concern.
| soheil wrote:
| Makes sense, yeah maybe they should have a window on the
| display instead of a fixed time.
| inamberclad wrote:
| The explosion was fine and expected. They mentioned this in the
| livestream, although it looks like the FTS and not aerodynamic
| forces. Either way, it happened after the capsule was well
| clear.
|
| Regarding splashdown timing, we will see. They've been testing
| this extensively in the background, and parachutes have been a
| pain point all around.
| soheil wrote:
| The explosion seemed very much like a controlled detonation
| and not a breakdown of the rocket as it falls through the
| atmosphere as was mentioned in the livestream so it seemed
| like an unplanned or unexpected explosion.
| CrazyStat wrote:
| You have a bunch of rocket fuel and a very hot rocket
| engine in close proximity when the booster starts to break
| apart. The explosion was entirely expected.
|
| I also have no idea what an unplanned or unexpected
| controlled detonation looks like. It seems like a
| controlled explosion has to be planned or expected by
| definition?
| lutorm wrote:
| I'm not sure what argument you're trying to make, on the
| one hand you say the explosion looked like a controlled
| detonation, on the other that it seems unplanned.
|
| Like others have pointed out: as far as F9 was concerned,
| the test ended when Dragon detached. Whatever happened
| after that point is immaterial to the test, so to start
| saying that would require a reflight is nonsense.
| soheil wrote:
| The plan was an explosion due to free-fall and
| atmospheric forces. The plan was not for an explosion due
| to a controlled detonation. I hope you are able to
| delineate between the two and not do a cursory reading of
| my comment again.
|
| > so to start saying that would require a reflight is
| nonsense
|
| I said "most likely" and "if you want to be safe enough"
| I'm not sure why you assumed I meant "require"
| JshWright wrote:
| > The plan was not for an explosion due to a controlled
| detonation.
|
| What evidence do you have that it was a "controlled
| detonation"? Seems like you're making baseless
| assumptions and then getting upset when people don't
| understand what you're trying to say.
| lutorm wrote:
| Because you also said "... or they will let it be as is
| which _would be_ unsafe? "
|
| I think your reception here would be better if you
| dropped the attitude and recognized that your comment
| used pure speculation to imply that the outcome of the
| test was negative. Maybe that was not your intent, but
| then you should have asked more open-ended questions
| rather than slant them so obviously negatively.
| Pfhreak wrote:
| When rockets, full of liquid oxygen and propellant, start
| to break apart in the atmosphere they pretty quickly look
| like a an explosion.
|
| A rocket with no nosecone will basically lose structural
| integrity very, very quickly. A rocket 'breaking down'
| doesn't look like fluttering bits and bobs raining down, it
| looks like a big fireball.
| soheil wrote:
| This makes sense. From footage of past explosions when
| the booster disintegrates, it's usually falling down.
| That's why I thought it was unexpected that it just blew
| up so quickly after the capsule was jettisoned.
| ddevault wrote:
| This is nonsense. The rocket was expected to explode.
| That's basically the only thing it can do once the dragon
| escapes.
| soheil wrote:
| It is insane how willfully someone with over 20k karma
| points on HN ignores the details of what I'm referring to
| (the manner in which it exploded not that it exploded)
| and bluntly assumes the dumbest thing possible about a
| somewhat neutral statement.
| endothrowho333 wrote:
| You wrote a very poorly structured, punctuation-less,
| run-on sentence in the GP comment.
|
| You did so again here.
|
| In both instances it is unclear what you're trying to
| convey.
|
| Coupled with taking a neutral comment personally, the
| simplest conclusion to make is that you're not writing
| for the benefit of anyone else, besides yourself.
|
| Language's primary function is to communicate
| information. Our minds are like compilers that translate
| human-readable language into simplified neural impulses.
| If you write code with poor syntax, the human mind will
| still compile it, but you're going to get a lot of
| unexpected behavior, i.e "what the fuck is this guy
| trying to convey?"
| martindevans wrote:
| I _think_ what you're getting at is that the flight
| termination system triggered (controlled explosion) but
| not when it should have (unplanned)?
|
| As far as I understand it once the capsule ejected the
| Falcon 9 was destinated to break up (due to aerodynamic
| forces) and that break up would trigger the FTS
| automatically. So the AFTS triggering was part of the
| plan.
|
| That said it also doesn't really matter - the test was
| about what happens to the capsule when something goes
| wrong and not what happens to the booster.
| extropy wrote:
| The explosion was very expected. "Falcon 9 will likely break
| apart due to aerodynamic loads immediately following Crew
| Dragon's escape"
|
| https://www.reddit.com/r/spacex/comments/eq24ap/rspacex_infl...
| soheil wrote:
| It seemed controlled and not due to aerodynamic loads.
| rrmm wrote:
| It's immaterial either way. The booster isn't expected to
| survive an abort regardless of the reason for aborting.
| dredmorbius wrote:
| An unexpected booster failure mode would be well worth
| investigating.
|
| Nothing I've seen or heard yet suggests that the test
| experience was outside expectations.
| soheil wrote:
| It raises the question if the explosion was trigged by
| the self-destruct sequence and not as mentioned on the
| livestream by disintegration due to free-fall and
| aerodynamic forces, did the explosion happen too close to
| the capsule so as it might have adverse effects on the
| capsule?
| lutorm wrote:
| The system is designed to be able to abort from a
| deflagrating rocket without warning (although that was
| not the design of today's test, obviously). Today, Dragon
| was already well clear when the stage disintegrated 11s
| after the abort. Just eyeballing the footage, it's
| probably a km away.
| soheil wrote:
| Thanks for pointing that, it's obvious now that you say
| it. The next question is why didn't they just explode
| booster using the self-destruct sequence while the
| capsule is still attached to test a more realistic
| scenario?
| phpnode wrote:
| The explosion was not triggered by the self destruct
| system as has been pointed out to you repeatedly, and
| even if it were the system has been designed to work
| correctly in that scenario too (this is covered in the
| press conference).
| _Microft wrote:
| The Falcon 9 has an AFTS (Automatic Flight Termination
| System) that destroys the booster if it veers off course
| (which might take other parameters into account as well?)
| to avoid damage on ground.
|
| As far as I know the AFTS consists of a detonating cord
| that runs along the tanks for fuel and oxidizer and rips
| them open when triggered. The substances mix and deflagrate
| and only the massive parts will actually reach ground (or
| sea).
| greglindahl wrote:
| The cord unzips the tank, but deflagration wasn't
| expected because mixing should have been limited.
| mechhacker wrote:
| 4 chutes are currently out and just waiting for splashdown now.
|
| Looks like the test went well.
|
| Edit: Splashdown
| sidcool wrote:
| Seems all went well! Kudos SpaceX
| _Microft wrote:
| Photos are coming in on Twitter. Thanks to all photographers for
| the amazing pictures! If you're a photographer and don't want
| your photos to be linked to from here, please say so.
|
| Official (SpaceX) close-up video of the separation event / IFA:
|
| https://twitter.com/SpaceX/status/1218976479150858241
|
| Great shots of the fireball:
|
| https://twitter.com/GregScott_photo/status/12189514406910730...
|
| https://twitter.com/BrandonHSlam/status/1218923590260645889
|
| https://twitter.com/Mimikry_/status/1218937739590230016
|
| https://twitter.com/_flsportsguy/status/1218930068887613441
|
| https://twitter.com/thelanjampod/status/1218949597231489024
| (multiple frames)
|
| Falling booster or second stage (the ratio of black to white hull
| area is the same on both stages, so I can not tell which one of
| both it is):
|
| https://twitter.com/mike_deep/status/1218926880381902849/pho...
|
| Impact of said part on the surface of the sea:
|
| https://twitter.com/johnpisaniphoto/status/12189461666389401...
|
| Infrared images:
|
| https://twitter.com/turndownformars/status/12189257207366000...
|
| https://twitter.com/turndownformars/status/12189415996080783...
|
| In-flight abort test appearing on the weather radar:
|
| https://twitter.com/NWSSpaceflight/status/121892435399747584...
|
| https://twitter.com/wxmeddler/status/1218925147861790720
| (animation)
|
| Lift-off and others:
|
| https://twitter.com/TrevorMahlmann/status/121896406755938713...
|
| https://twitter.com/RDAnglePhoto/status/1218968896885215235
| (viewing angle and height suggests it was taken from the roof of
| the VAB (vertical assembly building))
|
| Splash-down of the capsule:
|
| https://twitter.com/FutureJurvetson/status/12189766841347153...
| (strange that Mr. Innsprucker called the parachutes white-orange.
| That looks rather like red?)
| notatoad wrote:
| none of those fireball pictures look real - did it actually
| look like that, or are those photos _really_ heavily processed?
| mikeyouse wrote:
| Link to the live video, explosion happens at ~19:35, it
| doesn't look too far off from the pics tbh.
|
| https://youtu.be/mhrkdHshb3E?t=1168
| LeoPanthera wrote:
| It looked like that on the live video too - but only very
| briefly. It was a moment in time.
| blixt wrote:
| Keep in mind that this is taken with zoom lenses and that
| you're seeing a lot of atmosphere between the camera and the
| camera. This reduces contrast a lot and in an attempt to make
| out more detail in editing it can end up looking a little
| more cartoony (as the dynamic range is compressed so you can
| see it on a computer screen).
| soheil wrote:
| At first glance they look heavily touched up/processed.
| icegreentea2 wrote:
| What about them look unreal? Is it the relative darkness of
| the actual fire? The photos are processed to some degree -
| the cameras look to be setup for ultrafast (which makes
| sense, its trying to capture an explosion), so you can see a
| lot of "low light" noise and artifacts.
|
| Remember that if you're like me, 99%+ of fireballs that I've
| ever witnessed were also made up / post processed for maximum
| impact. Reality could just be more mundane.
| notatoad wrote:
| it's hard for me to articulate why they look fake, bu i
| think maybe they look like the photos are really faded and
| then had colour painted back onto them. something just
| seems weird.
|
| but as you say, most fireballs i see are post-processed to
| hell, that's why i'm curious what's up with these - are
| they more or less post-processed than normal?
| baq wrote:
| the parent already posted it but it's worth repeating -
| you're seeing the effect of multiple miles of air between
| the object and the lens.
| JshWright wrote:
| It looks like most of them were tweaked pretty heavily to try
| to highlight more detail through the clouds.
| tlb wrote:
| It's a methane fireball. Most other rocket explosions you've
| seen are hydrogen, which are more blue.
| gpm wrote:
| Kerosene (RP1) not methane, their next rocket will be
| methane but this one isn't.
| m3kw9 wrote:
| Like Street fighter yoga fireball?
| _Microft wrote:
| Note the official SpaceX video I just added to the list and how
| gases are vented from the bottom of the second stage shortly
| after the abort. May that have been overpressure in the tank(s)
| caused by the hot exhaust of the SuperDracos in proximity of
| the tanks? So many questions...
| whoisthemachine wrote:
| While the tried and true method of splashing down in the ocean
| seems like a reasonable first effort for landing the dragon
| spacecraft, watching the difficulty the boats have in reaching
| the spacecraft (the hosts of the stream mentioned it takes them 2
| hours!), and the difficulty the SpaceX team had in getting
| reasonable weather conditions for this test, it seems to me that
| a propulsive land-based landing would still be a reasonable
| future improvement to pursue.
| fit2rule wrote:
| I think you misunderstood the announcer - the recovery takes 2
| hours, but that's not how long it takes the boats to get to the
| capsule at its splashdown location.
|
| The boats get there pretty quickly.
|
| The time required is for safety checks and so on - there's some
| pretty nasty materials involved in those thruster engines, and
| all that stuff has to be checked first.
| whoisthemachine wrote:
| Interesting, so given this do you think that a normal landing
| would not have as long of a recovery time, given that it
| won't use those thruster engines?
| greglindahl wrote:
| For a normal landing, there's an extra step of hoisting the
| entire capsule onto the ship before opening the hatch.
| skunkworker wrote:
| In addition to this. The Air Force has personnel that can
| jump out of the plane with flotation, medical equipment and
| food in order to survive for an extended period of time on
| the ocean while it may take a few hours to get fast boats and
| recovery teams there.
| C14L wrote:
| NASA didn't require it. There was an early plan at SpaceX to
| have Crew Dragon land propulsivly, but they didn't pursue it in
| favor of developing Starship and SuperHeavy faster. That's what
| Musk said in an interview some time ago.
| whoisthemachine wrote:
| I remember that. It still seems to make sense to research
| propulsive landings and gain NASA's approval for them
| eventually (while maintaining the well-proven water landing
| capability) if it would cut costs significantly.
| C14L wrote:
| From what I remember, after Dragon2 is approved by NASA,
| all development efforts of SpaceX will be focused on
| Starship and Super Heavy only.
|
| Dragon2 is no use in the efforts to build a city on Mars.
| And even for a Moon colony, its too small. Its just there
| to earn money from flying people to the ISS and back. And
| for that its already good enough.
| greglindahl wrote:
| Losing science return cargo from a landing failure during
| testing is a no-no.
| jessriedel wrote:
| Boeing's Starliner lands on solid ground after a normal mission
| while SpaceX's Dragon lands in the ocean. But that's not
| relevant to an in-flight abort. Any abort at this stage in the
| launch (whether Boeing or SpaceX) has to come down over water.
| That's simply where the trajectory of the launch goes.
| Already__Taken wrote:
| Was crew dragons plan back with normal propulsive landings to
| always fly back to ground and just load more fuel?
| whoisthemachine wrote:
| As I replied elsewhere, for an abort, a water landing
| definitely makes sense (and is likely the only reasonable
| option). I was merely commenting on how drawn out the
| recovery process is after splashdown, which I would assume
| would be less time-consuming with a land landing.
| brianwawok wrote:
| Your odds of hitting something hard are much higher on
| land. Or smooshing someone.
| Fronzie wrote:
| In the introduction of the space-x launch broadcast, they
| mention that in real aborts, military will be involved.
| With helicopters, rescue personnel will be dropped of.
|
| Also there, it still takes a while for boats to arrive.
| _ph_ wrote:
| My understanding is, that the Nasa didn't like the idea of
| propulsive landing. As the dragon capsule is purely for
| supporting the ISS, SpaceX has no incentive to spend money on
| anything they are not using for the Nasa missions. For
| everything else, they are developing the Starship. If that
| program goes as planned, the dragon capsule will be used only
| for a short time, I guess.
| iso1824 wrote:
| > If that program goes as planned, the dragon capsule will be
| used only for a short time, I guess.
|
| I can't see Starship being approved for Nasa use by 2024 even
| if it were flying today.
| JshWright wrote:
| Why not? It didn't take that long to certify Dragon, and
| most of the delays were on SpaceX (like blowing up the
| capsule they were originally intending to use for this
| test).
| Klathmon wrote:
| I _believe_ SpaceX isn 't working with NASA to get Starship
| human rated by them. I think they are trying to do it 100%
| private, partially so they don't need to prove it to NASA's
| standards.
| grey-area wrote:
| _it seems to me that a propulsive land-based landing would
| still be a reasonable future improvement to pursue._
|
| They're working on a second stage that can carry a few more
| astronauts and land itself, it's a bit bigger though ;)
|
| https://www.spacex.com/starship
| whoisthemachine wrote:
| Yes, I'm well aware of that! Hopefully, they get that flying
| so soon that pursuing more advanced landing methods for the
| dragon is not needed :)
| whoisthemachine wrote:
| Interestingly, in the press conference, Musk mentioned that
| SpaceX would like to try to catch spacecraft, which I would
| think would reduce some of the water landing costs.
| davedx wrote:
| If you were the astronaut and it was an emergency that
| triggered the abort (e.g. the launch vehicle blew up like the
| Falcon 9 just did), would you really prefer the Dragon tried to
| land instead of at sea?
|
| Keep in mind it wouldn't be able to choose its landing site
| either.
| whoisthemachine wrote:
| As I replied elsewhere, for an abort, a water landing
| definitely makes sense (and is likely the only reasonable
| option). I was merely commenting on how drawn out the
| recovery process is after splashdown, which I would assume
| would be less time-consuming with a land landing.
| mechhacker wrote:
| That would require significantly more fuel and a different
| design, likely limiting the Dragon's crew payload.
|
| This abort happened after the rocket reached max Q (highest
| dynamic pressure) when it was flying East (and still upward,
| but to get to orbit you must fly sideways over water).
| Returning West to get back over land would be fuel prohibitive
| on a fully loaded crew capsule.
|
| The reusable falcon 9 stages have almost nothing in them when
| they fly back to land.
|
| See trajectories: https://i.redd.it/xaisqxao5ef01.png
| whoisthemachine wrote:
| For an abort, a water landing definitely makes sense. Perhaps
| there is no way to avoid the tough weather requirements for
| the downrange abort. The lengthy recovery time still seems
| due to the water landing, however. I wonder if it will be a 2
| hour recovery time during normal water landing?
| whoisthemachine wrote:
| I still wonder how much more difficult it is to get proper
| weather conditions over open sea vs. land when preparing to
| land during a normal flight. I'd imagine strong winds
| become stronger over sea than over land, and of course, the
| ability for ships to reach you in choppy seas becomes much
| more difficult.
| shkkmo wrote:
| That was the original end plan, but AFAIK it was mixed a couple
| of years ago.
|
| "The reason we decided not to pursue (powered landings) heavily
| is it would have taken a tremendous amount of effort to qualify
| that for safety, particularly for crew transport," Musk said.
| "And then there was a time when I thought that the Dragon
| approach to landing on Mars, where you've got a base heat
| shield and side-mounted thrusters, would be the right way to
| land on Mars, but now I'm pretty confident that is not the
| right way, and that there's a far better approach." [0]
|
| [0] https://spaceflightnow.com/2017/07/19/propulsive-landings-
| ni...
| lutorm wrote:
| To be clear, propulsively landing after an abort was never
| planned -- you've already used up the fuel doing the abort.
| Plus, depending on when you abort, you could be half-way
| across the Atlantic.
| mechhacker wrote:
| Do you know if they had a path for redundancy for a
| propulsive abort? With 4 parachutes, they likely have the
| design able to handle a single 'chute failure. Not sure
| what would be involved with single failures on the
| propulsive abort but that may have been a large contributor
| to go with the required return fuel.
| greglindahl wrote:
| The propulsion is pairs of engines for redundancy, but,
| as people keep on saying, abort was always going to be
| parachutes.
| lutorm wrote:
| The abort _is_ the redundancy... ;-) I 'm not sure what
| specifically you are thinking about, but in general since
| an abort is already one critical fault away from the
| nominal case, I believe the requirements for redundancy
| are lower.
| ragona wrote:
| Do you happen to know how long the crew is safe to be out
| in the middle of the Atlantic if it's a particularly non
| optimal landing location?
| prox wrote:
| Thats why you have the team who tracks the capsule by
| plane, they jump out with a raft that can survive several
| days on rough waters. The capsule is pretty sturdy I
| assume to stay in for some time.
| ragona wrote:
| Okay that is pretty damned cool. Thanks!
| [deleted]
| chasd00 wrote:
| is it just me or was the water deludge system late at liftoff?
| davedx wrote:
| Nailed it!
|
| Can't wait for the crewed launch. Historic moment for the United
| States space program.
| shkkmo wrote:
| Any idea when that will get approved?
| lhoff wrote:
| I heard that the first flights are scheduled for first
| quarter 2020 if everything goes well today, which it from the
| first look did.
| olmideso wrote:
| At the press conference Elon said that all remaining tests
| are expected to be finished by the end of Q1 2020 and the
| first flight is expected to launch in Q2. Of course they have
| to analyze the data from today's test.
|
| Also the flight can be delayed if NASA decides to extend
| astronauts' time on ISS which would require additional
| training for them.
| vsareto wrote:
| Why did the booster explode? No thrust causing it to lose
| direction?
| hoorayimhelping wrote:
| The pointed nosecone on the top of the rocket came off and it
| lost aerodynamic stability, and started to tumble. The tumbling
| caused the fuel and oxydizer to slosh around the very thin (and
| lightweight) tanks that are not designed with withstand that
| kind of force. The sloshing accelerated the tumbling. The thin
| tanks rupture causing the fuel and oxidizer to mix in the
| vicinity of a lit rocket engine. BOOM.
| code4tee wrote:
| Given the velocity it was going the capsule popping off the top
| basically turned the rest of the rocket into a supersonic
| flying brick. The amount of drag would be enormous and the rest
| of the ship basically just tore itself apart. As soon as the
| oxidizer and fuel combined in the crumbing mess you get a big
| explosion.
|
| That was all expected to happen and why they launch these
| things out over the ocean. These rockets also usually have a
| self-destruct mechanism that a range safety officer can trigger
| if the rocket starts coming back towards land.
| rtsil wrote:
| Falcon 9's self-destruct is automatic since a couple of years
| now.
| xenospn wrote:
| Do they actually go around collecting all of the various
| parts that fall back into the ocean? I imagine that's a
| huge amount of debris.
| goshx wrote:
| They mention in the stream that it was not going to be used
| today.
| bonestamp2 wrote:
| I suspect they'll still log when it would have happened
| so they can confirm it was working properly. That would
| be interesting to hear about.
| 0xTJ wrote:
| Based on what they said, I'm assuming that it would have
| been triggered at some point before it started coming
| down, but they were expecting that it would be destroyed
| before that happened.
| JshWright wrote:
| The upper stage hit the ocean intact. That suggests the
| FTS was not triggered (or it was triggered and failed to
| destroy the stage, which would be more concerning)
| twexler wrote:
| Pretty sure there was a call out late in the countdown
| regarding arming the FTS.
| vibrolax wrote:
| They armed the FTS, as they would need that if the range
| safety officer needed to do that. But it was not needed
| or used by the RSO.
| usrusr wrote:
| At some point there must have been a mission design meeting
| for this test where they decided on fuel levels in the
| booster. Just as much as needed to get to max Q? Just like a
| real launch that would put the capsule into orbit and land
| the booster? Something in between that creates a nice
| fireball but not too wasteful?
|
| (and on an entirely unrelated note, I really hate watching
| those parachutes bounce off each other. I know it must be
| perfectly safe or else it wouldn't have been the unquestioned
| method off choice for at least half a century, but it looks
| so uncontrolled it gives me nausea)
| greglindahl wrote:
| Well, the decision was to fully fuel everything, including
| the second stage. Which had no engine.
| Klathmon wrote:
| And even thought it had no engine, it had a "mass
| simulator" to replace it.
| joshvm wrote:
| You want to test this stuff as realistically as possible.
| Changing the amount of fuel means changing launch weight
| which means (presumably) changes in throttle profile etc.
| The control systems are also probably designed with a
| certain weight to reach orbit so it's possible that an
| unusually light rocket would be unstable.
|
| I'm not sure whether this would actually make a difference,
| but if you know it works at nominal fuel weight then you
| have some confidence it would work during a real launch.
| HALtheWise wrote:
| In addition to the loss of the aerodynamic nose, it also
| started tumbling simply because the engines were powered off.
| Modern rockets, falcon 9 included, are not actually
| aerodynamically stable during flight, and rely on active
| controls from gimballing the engines to keep pointed in the
| right direction. Once the engines power down, the rocket has
| little chance of surviving.
| CarVac wrote:
| The automated flight termination system may have detonated it
| due to it deviating from the "planned" flight path.
|
| It looked too instantaneous and clean of an explosion to have
| broken up naturally.
| olex wrote:
| There are pictures of the second stage coming down in one
| piece and exploding upon hitting the water (at a safe
| distance away from the capsule and recovery crews). So it
| certainly doesn't look like the flight termination system was
| engaged.
| bob1029 wrote:
| The SpaceX FTS should be fully-automated per this test. It
| is one criteria that still needs to be certified for the
| commercial crew program. That entire sequence should have
| been performed automatically by a computer (throttle
| back->fire abort rockets->terminate stage 1 booster).
|
| I suspect the FTS was appropriately triggered and that the
| 2nd stage simply survived the initial carnage via
| happenstance or potentially unintentionally due to changes
| in the structure regarding the missing front piece.
| JshWright wrote:
| The webcast hosts explicitly said the FTS wouldn't be
| triggered.
| _Microft wrote:
| Yes, it definitely looked different from the CRS-7 launch
| anomaly.
| JshWright wrote:
| CRS-7 started as a failure of the second stage, at much
| higher altitude. The cloud of gas from the ruptured upper
| stage tanks would have obscured much of what was going on
| with the booster.
|
| It was a very different "failure", which would naturally
| look different.
| _Microft wrote:
| The overpressure from the burst helium COPV ruptured the
| second-stage tanks and spilled the contents. We didn't
| really see clouds of unburnt fluids or gases this time,
| it was an explosion right from the start. That's what I
| meant when I said it looked different this time.
| JshWright wrote:
| Right, but your explanation for those differences seemed
| to be (based on the context) related to whether or not
| the FTS was triggered.
| _Microft wrote:
| Yes, I actually meant to say that the sudden explosion
| did not look like CRS-7 which had this spilling-a-dewar
| look and guessed that the AFTS might have been involved.
| It was really nothing more than a wild guess.
| lutorm wrote:
| I agree, although CRS-7 was higher altitude so the
| atmospheric pressure and aerodynamic forces were smaller,
| so that may not be unexpected.
| fit2rule wrote:
| It was intended to be disposed of this way. I too wonder
| whether it was demolished by way of explosion, or if SpaceX
| instead used this opportunity to see what a non-optimal flight
| pattern would do to the structure ..
| [deleted]
| shkkmo wrote:
| It lost it's areodynamic nose cone and so started to tumble.
| [deleted]
| xt00 wrote:
| It was somewhat eerie to hear the "stage 1 throttle up" then
| abort just after that.. reminded me of the "go for throttle up"..
| some of you may know what I'm taking about.. I'm glad these guys
| will have an abort system available and testing in flight like
| this was awesome.. good job spaceX
| nrb wrote:
| For anyone unfamiliar: "go at throttle up" was the final
| communication to/from Space Shuttle Challenger during launch of
| mission STS-51-L moments before it tragically exploded,
| resulting in the loss of all crew. The Space Shuttle did not
| have a launch abort system.
|
| https://www.youtube.com/watch?v=sDnABgxUeV4
| zipwitch wrote:
| Challenger did not _explode_.
|
| The key events of the disaster took place over about three
| seconds.
|
| A leak of high-temperature gas in the right solid rocket
| booster damaged the external stack of solid rocket boosters
| and external fuel tank.
|
| The damage to the external tank caused it to come apart, and
| resulted in a fireball from the released liquid oxygen and
| hydrogen. The solid rocket boosters broke free of their
| mountings as the disaster unfolded.
|
| The Challenger orbiter momentarily survived both the fireball
| and external tank failure. But those events made it
| impossible to keep the orbiter correctly oriented.
|
| The loss of proper orientation while travelling ~1000mph
| meant Challenger was hit with very high stress forces, far
| beyond anything it was designed to survive, and swiftly broke
| apart.
|
| Shortly afterward, the Range Safety Officer remotely
| detonated both solid rocket boosters, which had survived the
| disaster mostly intact and were careening out of control.
|
| More detail at Wikipedia: https://en.wikipedia.org/wiki/Space
| _Shuttle_Challenger_disas...
| nrb wrote:
| It did indeed explode in the literal sense: rapid
| decomposition of the launch vehicle.
|
| I suppose it is worth mentioning that it did not "explode"
| in the sense people normally understand though: a blast of
| rapid combustion of fuel.
| Klathmon wrote:
| IIRC the word "explosion" has a very specific meaning in
| this context. I remember reading that the SpaceX AMOS-6
| failure was specifically NOT an explosion even though it
| really looked like one to a layperson.
| fourseventy wrote:
| King of pedantry over here...
| LeoPanthera wrote:
| > The Space Shuttle did not have a launch abort system.
|
| Challenger did not. Later shuttle launches included the
| "Inflight Crew Escape System", or ICES.
|
| https://spaceflight.nasa.gov/shuttle/reference/shutref/escap.
| ..
| Teknoman117 wrote:
| ICES was not a launch abort system. It was a way for the
| astronauts to bail out of the shuttle _after re-entry_ if
| they weren't going to be able to land the shuttle safely.
|
| The only shuttle to ever was anything resembling a launch
| abort system were the first few flights of Columbia. It had
| ejection seats for the pilot and commander. However, later
| statements by NASA and the astronauts said that using them
| probably would've resulted in the death of the astronauts
| due to descending through the extremely hot exhaust of the
| launch.
| JshWright wrote:
| Just a little more detail, the "throttle up" had nothing to
| do with the anomaly, it just happened at that stage in
| flight.
| [deleted]
| wilg wrote:
| This is a good opportunity to plug the under-the-radar TV
| movie from a few years ago about Richard Feynman and the
| Challenger investigation.
|
| Slightly hard to find digitally but it's the first "episode"
| here: https://smile.amazon.com/The-Challenger-
| Disaster/dp/B00GQUM7...
|
| William Hurt does a great job in it and its pretty
| interesting!
|
| (Be careful because there's also a worse seeming/rated movie
| with the same name that came out recently.)
| beached_whale wrote:
| It was really interesting how they setup the main chutes to open
| slowly to minimize the shock from breaking.
| iso1824 wrote:
| Looked exactly like KSP
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