[HN Gopher] Space Station incident demands independent investiga...
___________________________________________________________________
Space Station incident demands independent investigation
Author : multivac42
Score : 367 points
Date : 2021-08-08 02:21 UTC (20 hours ago)
(HTM) web link (spectrum.ieee.org)
(TXT) w3m dump (spectrum.ieee.org)
| _RPL5_ wrote:
| Here is a piece of commentary from a Russian insider covering the
| launch of Nauka, but not the docking, in Russian [1]. There was a
| litany of smaller issues with the launch, probably stemming from
| the fact that the module has been tossed around for 25+ years.
|
| I generally don't expect Roskosmos to make any comments regarding
| Nauka unless it blows up or something. Part of the reason,
| apparently, is that Roskosmos is being assessed for new funding
| (from the blog post, Google translate edited for clarity):
|
| """
|
| Docking is scheduled for July 29. The future of Russian manned
| astronautics depends on its success. With Nauka, the Russian
| segment will be able to operate for another 10 years, and be more
| effective as a research platform.
|
| The future of the independent Russian Orbital Service Station
| (ROSS) is also indirectly related to the success of Nauka. With
| Nauka, Roskosmos gets a chance to show that it has the ability to
| create and launch manned space stations. This, in turn, increases
| the likelihood of obtaining the funding for ROSS.
|
| Probably, this is the reason that Roscosmos has been reluctant to
| voice any of the problems with Nauka. When half a trillion rubles
| is at stake, you will inevitably lose your voice.
|
| """
|
| Half a trillion rubles is about $7bn American. I've been hearing
| about plans for this new station for a few years now. I don't
| really know if it's real. Involvement with the ISS, where
| Americans shouldered 80% of the financial burden, is really what
| kept the Russian space program relevant. So I don't expect us to
| pull out of the ISS voluntarily. If the ISS ends up being
| decommissioned this decade, hopefully we can piggy back with the
| Chinese on their new projects or something. That's assuming we
| have anything they want, which is a big question mark come year
| 2030.
|
| [1] https://zelenyikot.livejournal.com/158629.html
| mschuster91 wrote:
| > hopefully we can piggy back with the Chinese on their new
| projects or something
|
| The US won't touch China with a ten feet pole for anything
| space-related (and vice versa). The best the US may see is a
| bit of cooperation with the EU - assuming we can solve our
| internal post-covid and euro-skeptic squabbles - and that's it.
| ascar wrote:
| He's obviously talking from a Russian point of view.
| [deleted]
| vagrantJin wrote:
| And thank god. My theory
|
| China and Russia should form their own platform for future
| space explorations.
|
| The EU should really have their own thing and collab with
| both West and East. The US can do whatever.
|
| The China/Russia alliance could probably work with "other"
| BRICS nations not entirely known for space research.
| PicassoCTs wrote:
| Wasn't there a plan for "dual" use, aka the next space station
| can be equipped with a drive and used as a long range spaceship
| if needs be?
| NickNameNick wrote:
| There were plans to launch a VASIMIR Ion drive for testing -
| The ISS was the only thing in space with enough electrical
| power to test it.
|
| Apparently NASA lost interest around 2015.
|
| I think I read something about assembling a manned mars ship
| out of re-used ISS or new ISS-like parts, but I can't recall
| where, or if the proposal was serious.
| rbanffy wrote:
| It'd need additional radiation shielding to operate for
| long periods outside Earth's magnetosphere. The Lunar
| Gateway modules are a reasonable blueprint for this.
|
| Also, even with the ISS's power budget, the VASIMR module
| wouldn't operate continuously. The plan was to charge it
| and then run it for short 15 minute periods. It could
| operate for longer if it took more power from the ISS. It
| seems they are considering other options for a flight
| demonstration.
| _RPL5_ wrote:
| This sounds like something from a sci-fi novel.
|
| The only tangible new thing in production is the Angara heavy
| rocket that will replace Protons. It's an actual thing that
| exists and flies. There is also a new piloted ship
| (Eagle/Federation) in development tailored for Angara, but I
| don't expect to see it in serial production until late 2020s.
|
| Beyond these two things, everything else is basically concept
| art.
| JNRowe wrote:
| FWIW, it actually _is_ part of an old sci-fi novel,
| featuring in Arthur C. Clarke 's 20101. China suddenly
| joins a race to Jupiter by firing up its "space station".
|
| 1 https://en.m.wikipedia.org/wiki/2010:_Odyssey_Two
| jollybean wrote:
| How is it possible for thrusters to fire without a) human
| oversight and b) nobody knowing?
| jjk166 wrote:
| It's an autopilot with no communication connection. What would
| be the alternative, drifting uncontrolled whenever it's outside
| of communication range?
| jollybean wrote:
| It's not out of 'communication range' with personnel aboard
| the station.
|
| An ultra basic integration of alarms and communications would
| be the minimum requirement to allow personnel to monitor and
| modify mission critical systems.
| jjk166 wrote:
| It was prior to docking. It was a separate entity which had
| to fly itself without continuous communication to the
| station in order to be integrated. The entire problem was
| that the module did not recognize that it was docked with
| the station and was trying to maneuver itself. Why would
| you put in a "tell the station to which you are attached
| that you are firing your thrusters which should never be
| fired while attached to the station" signal?
| kfarr wrote:
| It's not a crazy suggestion to have ability for an
| emergency stop or docking success signal sent from the
| station to the module.
| jjk166 wrote:
| The problem was that the "docking success signal" was not
| properly recieved.
|
| The very presence of an emergency stop system should be a
| signal that the thrusters should not activate, if you are
| ever in a situation where you would desire to send an
| emergency stop signal, it is because that emergency stop
| system has already failed.
| jollybean wrote:
| "The problem was that the "docking success signal" was
| not properly recieved."
|
| Then it's _not docked_ and docking procedures should be
| observed by all personnel as a serious ongoing
| operational concern, right?
|
| So, if there is integration, which there hopefully would
| be, that there wasn't proper integration would imply
| something bad.
|
| Otherwise, while the crew obviously believed it to be
| docked, why wasn't the auto-correcting features etc. on
| the Russian module disabled while it's docked?
|
| Again, as part of the docking procedure?
| MrStonedOne wrote:
| Docking brackets can carry electrical contacts and SPI
| with redundant conductors would more then cover this
| usecase.
| jjk166 wrote:
| That system exists, the problem is that's the thing that
| failed here. The module didn't recognize it was attached
| to the station explicitly because there was an issue with
| those connections.
| alisonkisk wrote:
| a) software
|
| b) outer space
| ComodoHacker wrote:
| Simple: the module was out of comm reach at the moment.
| jollybean wrote:
| That's not 'simple'. The module should be integrated with the
| other modules such that any control terminal on the station
| should highlight that information.
|
| Moreover, one would imagine that applying thrust should
| generally require some oversight and that it should not be
| automated unless there's an emergency in which case there
| would be appropriate alarms.
| NavinF wrote:
| The module will be integrated over the next few months.
| It's not as simple as just docking the module and expecting
| all the wiring and software config to kick in
| automatically.
| MrStonedOne wrote:
| It could be thou.
| atatatat wrote:
| "Computers never lie, kid!"
| krisoft wrote:
| I tell you how it is possible: it is both a bug, and a design
| issue.
|
| To say anything deeper about the whys one would need that
| investigation.
| mannykannot wrote:
| NASA's response, printed as an addendum, contains the sort of
| non-sequiturs that, contrary to the presumed intention, can only
| suggest that NASA is doing exactly what is alleged here: hoping a
| serious issue will go away.
|
| "As shared by NASA's Kathy Lueders and Joel Montalbano in the
| media telecon following the event, Roscosmos regularly updated
| NASA and the rest of the international partners on MLM's progress
| during the approach to station..."
|
| As far as we know, nothing untoward happened during the approach
| to station. Restricting this comment to this period renders it
| irrelevant and signals that NASA is trying to avoid the issue.
|
| "When the unexpected thruster firings occurred, flight control
| teams were able to enact contingency procedures and return the
| station to normal operations within an hour..."
|
| So there's no need to be concerned over why it happened, how long
| it took to discover the problem, or the inability of those at
| NASA who discovered it to counteract it until the ISS was in a
| position where Roscosmos could intervene? As the article author
| points out, this "all's well that ends well" attitude is what led
| to the Challenger and Columbia crashes.
|
| "We would point you to Roscosmos for any specifics on Russian
| systems/performance/procedures."
|
| So, NASA seems to be saying, it is not _our_ problem - but, of
| course, anything that threatens the integrity of the ISS most
| definitely is.
|
| That covers the whole of NASA's response so far to IEEE Spectrum,
| other than the utterly anodyne "We continue to have confidence in
| our partnership with Roscosmos to operate the International Space
| Station."
|
| What I would like to know is why public relations spokespersons
| think it is in the interests of their organizations to make those
| organizations look clueless, while simultaneously insulting our
| intelligence by implying we will fall for this nonsense?
| knolax wrote:
| > That covers the whole of NASA's response so far to IEEE
| Spectrum
|
| IEEE Spectrum was the same paper that got duped into publishing
| a story about a self driving car that didn't exist. It's a
| tabloid piggybacking off of the IEEE's brand recognition. The
| fact that a NASA spokesperson bothered to reply at all
| surprises me.
| Denvercoder9 wrote:
| Alternatively, NASA doesn't want to sour the relation with
| Roscosmos while the investigation is ongoing, and what's said
| publicly isn't an indication of what happens behind the
| screens. At this level, there's a lot of politics involved as
| well.
| destitude wrote:
| Or they could simply say we are continuing to investigate. So
| does sound more like they are trying to get people to ignore
| it.
| icegreentea2 wrote:
| You're right, they could be trying to get people to ignore.
| I think it's more likely they're in an awkward
| political/diplomatic holding pattern.
|
| They definitely can't say that they are continuing to
| investigate unless they've been cleared to do so, since
| investigating starts implying patterns of responsibility.
|
| It's definitely a gong-show.
| irjustin wrote:
| In principle I agree, but there's a lot riding against a proper,
| non-nasa investigation.
|
| 1. No one died, unlike Columbia, there won't be a Congressional
| committee put together on this.
|
| 2. Even if there was a congress committee/investigation done,
| what changes can actually be instituted? Block any more Russian
| modules?
|
| That's requiring putting pressure on a foreign country to make
| changes where the relationship runs a knife edge balancing act of
| frenemy.
|
| The Russian space program is a shell of its former self since
| ~2010.
|
| The most realistic course of action (at this moment) of any
| corrective recommendation is to remove them from the ISS. They've
| been threatening pulling out for a few years now, so let them?
| SideburnsOfDoom wrote:
| > No one died
|
| In areas with a strong and proactive safety culture, "near
| miss" incidents are investigated and mitigated. These "near
| misses" are cases where "no one died" - the accident did not
| happen, but if one more thing had gone wrong, it would have.
|
| The manta is "for every _x_ near misses, there will be an
| actual accident". Where x could be e.g. 10; and accident in
| this case could mean "total loss of the ISS and everyone on
| board"
|
| This is IMHO a strong argument for a thorough investigation, in
| some form. Congressional committee or not.
|
| https://en.wikipedia.org/wiki/Near_miss_(safety)
|
| https://etraintoday.com/blog/near-miss-vs-an-accident/
| irjustin wrote:
| Clearly there will be an internal investigation with NASA
| (too much happened outside of protocol) but we'll never hear
| the full details nor know of the corrective recommendations
| or lack there of.
|
| If you want to guarantee public knowledge it's got to be
| Congressional and I just don't see that being realistic
| because again... No one died.
| SideburnsOfDoom wrote:
| > but we'll never hear the full detail
|
| This is a pity, good safety cultures are also more open.
| ashtonkem wrote:
| There should be an internal investigation at NASA, but
| they've dropped the ball on that several times in living
| memory. It's a question of how much has changed culturally
| since Columbia.
| whoknowswhat11 wrote:
| Another issue - they've been doing things like having all their
| folks shelter in their modules when SpaceX docks - but not
| doing that for this type of stuff.
|
| Also the somewhat odd cracks at SpaceX
|
| Rogozin told Russian media that he doesn't believe SpaceX can
| build better rocket engines than Russia can. "Musk is not a
| technical expert in this matter," Rogozin said. "He just
| doesn't understand what this is about."
|
| Will be interesting to see how Raptor 2 competes (and yes,
| Russia has had amazing engines).
| nickik wrote:
| SpaceX destroyed the main funding for their space agency.
|
| Raptor 1 is already better then any Russian engine along most
| metrics.
|
| And Rogozin is a journalist made oligarch, he doesn't know
| shit. Accusing Elon of not being an expert is quite funny
| coming from him.
| jacquesm wrote:
| I don't think he was speaking to an international audience
| when he said that, even though it may appear to be like
| that. Russia is internally quite fragile and to admit that
| they lost their edge is something that comes with a pretty
| high price so - just like it always was - they engage in
| weak PR.
| oconnor663 wrote:
| What happened in 2010? Is that when the Falcon 9 started
| launching?
| _RPL5_ wrote:
| I am curious as to how you would remove us from the ISS. A
| third of the pressurized modules on the ISS are Russian [1]. Do
| we just take them with us when we leave? How do we achieve
| that?
|
| [1]
| https://en.wikipedia.org/wiki/Assembly_of_the_International_...
|
| """
|
| The ISS is made up of 16 pressurized modules: five Russian
| modules ( Zarya, Pirs, Zvezda, Poisk and Rassvet), eight US
| modules (BEAM, Leonardo, Harmony, Quest, Tranquility, Unity,
| Cupola, and Destiny), two Japanese modules (the JEM-ELM-PS and
| JEM-PM) and one European module (Columbus).
|
| """
|
| *Pirs was undocked to make place for Nauka.
| [deleted]
| Denvercoder9 wrote:
| Removing the Russian segment from the ISS isn't feasible, as
| it has the only module capable of GNC, and Progress is the
| only currently flying craft that can raise the ISS's orbit
| (which, being in LEO, slowly decays).
| jhgb wrote:
| Russians also can't remove Zarya anyway because they don't
| own it. The US purchased the module decades ago when
| Russians had no money. (They still have no money, but they
| used to have no money, too.)
| simonh wrote:
| I suppose in theory the US could just starve Roscosmos of
| funding by cutting back on implicit subsidies. That would
| require having a contingency in place to keep the station
| viable without Russian involvement. The problem is that would
| be massively expensive. As you say, that's a third of the
| station. In practice you're quite right, that plan is
| completely unviable.
| gambiting wrote:
| Well it's doable, the problem is that it would kill the ISS
| as a station. If other parties are ok with it then sure,
| but I somehow doubt they are.
| TedDoesntTalk wrote:
| Probably US would pay Russia for keeping them in place.
| nine_k wrote:
| If we imagine an offer to buy out 1/3 of a space station,
| how much would it be? The amount should be colossal.
| TedDoesntTalk wrote:
| It would not be any more expensive than what Russia spent
| to build that portion. Moreover, accounting for
| depreciation, it's not at all colossal.
| nine_k wrote:
| If it were reasonably easy to just replace the existing
| modules, they coukd have been replaced.
|
| But if you want these specific modules, already
| integrated into the station, which are an opposite of a
| commodity, the price includes a _significant_ premium.
| rbanffy wrote:
| Russia wouldn't let the US operate them.
| baybal2 wrote:
| > The most realistic course of action (at this moment) of any
| corrective recommendation is to remove them from the ISS.
| They've been threatening pulling out for a few years now, so
| let them?
|
| From my experience of life in Russia, I'd say this is one of
| the most effective ways dealing with people habitually
| resorting to the "do ... or we will sink together!" blackmail.
|
| Let the saboteur succeed, and exceed.
|
| You can swim, and the blackmailer likely cannot (and choosing
| the threat exactly for them fearing such outcome.)
|
| If somebody brings a stick of a dynamite on the ship, shouting,
| and swinging it around, give them 10 more, and say good luck.
|
| Such demeanour is wholly dependent on the other party's
| assumptions that they are harmed more than if they did nothing,
| which is the reverse in reality.
| adventurer wrote:
| We've already called out the Russians and pressured them for
| sending up anti-satellite weaponry in 2017 and 2020. Why trust
| them here.
| perlgeek wrote:
| > 2. Even if there was a congress committee/investigation done,
| what changes can actually be instituted? Block any more Russian
| modules?
|
| There are certainly less dramatic measures that could have
| prevented this incident.
|
| To quote the article:
|
| > the Nauka module's autopilot apparently decided it was
| supposed to fly away from the station.
|
| Having such decisions protected by a physical switch comes to
| mind.
|
| A joint committee by all the nations involved in the ISS could
| require such measures before any module or spacecraft is
| allowed to dock.
|
| Establishing emergency overrides for firing thrusters to all
| ground control stations could have greatly reduced the impact.
|
| Why was the unexpected firing of thrusters detected so late?
| Better telemetry and their analysis could help.
|
| And so on. Lots of things that _could_ be done if there was the
| will do to do them.
|
| Many more things could be done in response to a through root-
| cause analysis.
| nathanaldensr wrote:
| Dupe: https://news.ycombinator.com/item?id=28103641
| mannykannot wrote:
| "the module began trying to line itself up in preparation to fire
| its main engines using an attitude adjustment thruster."
|
| One thing that I am curious about is what would have happened if
| the module had achieved the alignment it was seeking, either as
| as result of its own efforts or during the procedure to stop and
| correct for its actions. If the main engine was capable of
| firing, would there still be an ISS?
| nraynaud wrote:
| I think it's an alignment relative to the ISS (with the visual
| markers), so there was really no hope of reaching it.
| nraynaud wrote:
| by independent, do they mean neither American nor Russian?
| curiousllama wrote:
| The investigation would be about NASA's reaction, not the
| mistake itself. So Americans investigating Americans about a
| (potential) American problem.
|
| Russia's incidental to the nature of the trigger.
| [deleted]
| redis_mlc wrote:
| Does it matter what happens to the ISS?
|
| Is there any science done on the ISS that's actually cited?
|
| The answer to both questions is no.
| lmm wrote:
| If we can't keep people alive on a space station, how will we
| ever spread beyond a single planet? If we don't start trying
| now, then when?
| robinsoh wrote:
| > If we can't keep people alive on a space station, how will
| we ever spread beyond a single planet? If we don't start
| trying now, then when?
|
| Depends on your meaning of "we". As of June 17, 2021, the
| Chinese space station Tiangong, is manned. Chinese manned
| missions to Mars in 2030 have long been announced and may
| even be completed earlier than anticipated.
| nickik wrote:
| > Chinese manned missions to Mars in 2030 have long been
| announced
|
| Total nonsense. They wont even make it to the moon by then.
|
| Their Long March 9 rocket need for Mars will barley even
| fly before 2030, let alone will they make a Mars mission
| with it.
| ifdefdebug wrote:
| Where can I bet against Chinese manned missions to Mars in
| 2030?
| Zababa wrote:
| Look up "predictions markets".
| robinsoh wrote:
| Why would one want to bet against that? Aren't we
| supposed to want humanity to progress?
| ifdefdebug wrote:
| I'd want to bet against because I don't believe it's
| gonna happen so I think I can win some money. On the
| other hand, if it's really going to happen, I'd be
| thrilled and more than happy to lose that money. So
| betting against it is win-win for me :)
| Cipater wrote:
| Will it make you happy if they fail?
| ifdefdebug wrote:
| Betting on things that would make me happy doesn't win me
| money does it? I bet on things I believe/do don't believe
| in, regardless of what makes me happy.
| ndkwj wrote:
| Why do we have to spread beyond the earth?
| sokoloff wrote:
| Failure to do so ensures our eventual extinction. That's
| motivation for many.
| guenthert wrote:
| It's our manifest destiny.
| CamperBob2 wrote:
| _You_ don 't have to.
|
| And yes, I wish there were a way you could opt out of
| paying for manned spaceflight via your taxes, because that
| would mean that _I_ could opt out of paying for things that
| _I_ don 't want to pay for.
|
| But it doesn't work that way. Deal with it.
| TedDoesntTalk wrote:
| Who has died on a space station? Do you have some information
| everyone else does not?
| Kye wrote:
| Good starting point:
| https://scholar.google.com/scholar?hl=en&as_sdt=0%2C11&q=sit...
| perl4ever wrote:
| 1961...1974...1993...1967...
|
| If you add "ISS" and restrict to the 21st century, what do
| you find? I don't see anything with triple-digit citation
| numbers, or for that matter anything that looks like
| generally applicable research at all.
|
| I do see "ISS plasma interaction: Measurements and modeling",
| cited by 15.
|
| There is probably a better way to look for research than only
| at nasa.gov, but since you provided the link I was going with
| that.
| maxnoe wrote:
| Check for AMS papers, e.g.:
|
| "First result from the Alpha Magnetic Spectrometer on the
| International Space Station: precision measurement of the
| positron fraction in primary cosmic rays of 0.5-350 GeV"
|
| https://scholar.google.com/scholar?hl=de&as_sdt=0%2C5&q=alp
| h...
| xioxox wrote:
| There's also NICER
| (https://heasarc.gsfc.nasa.gov/docs/nicer/) and MAXI.
| daguava wrote:
| Does it even matter what you've done in a lifetime? Have you
| done any science worthwhile and cited? Last line :)
| anaganisk wrote:
| Does it matter what a random stranger on the internet thinks?
| But here we are trying to comment on everythingas if we have
| seen it all, from the comfort of our chair.
| kova12 wrote:
| if a groundbreaking science happened on the ISS, but some guy
| on the internet isn't aware of it, did it actually happen?..
| a422b wrote:
| if the U. S. President attends a live sporting event and all
| involved have instructions to show it but it never did was he
| ever the U. S. President?..
| harry8 wrote:
| If groundbreaking science happened on the ISS and someone
| wanted to know what it was, couldn't find it, asked, and
| nobody provided any examples or references despite it being
| pretty attractive to most of us? (The idea of doing science
| in the zero g of orbit). If that were the case I'd have to
| start updating my prior that groundbreaking science did
| happen. Let's see how that plays out over the next few days.
| But from my perspective it's just fan trivia. I will never go
| nor have any influence on funding decisions.
| gusgus01 wrote:
| I'm not sure what is considered groundbreaking science, but
| a lot, a majority of science even, is not groundbreaking.
| But offhand, the ISS provides us the ability to monitor the
| difference that microgravity has on humans, eg the twin
| study they've done as well as other studies on blood
| pooling and muscle loss. If we plan to ever have long term
| missions in space, like Elon Musk and his mars aspirations,
| then the ISS is an important stepping stone to understand
| the implications on human health and experience managing
| humans in space.
|
| It's pretty easy using Google to find some of the research
| that people have thought was notable:
| https://www.sciencefocus.com/space/five-things-the-iss-
| has-d... https://www.nature.com/articles/d41586-020-03085-8
| __s wrote:
| https://www.nasa.gov/sites/default/files/atoms/files/expedit...
| galgalesh wrote:
| Interesting, thanks for posting this!
|
| This amounts to a bit more than one peer-reviewed publication
| for every four days since the first ISS segment launched in
| 1998. (2157 publications total through March 2019)
|
| More than 170 of those papers have been published in the top
| 100 journals in the clarivate analytics ranking. (Independent
| ranking used by a large number of universities)
|
| Their top paper has been cited 582 times. (Context: For many
| top journals, average number of times a paper has been cited
| is ~5).
| redis_mlc wrote:
| Wow, I read the link - it's even worse than I thought. After
| 21 years in orbit, so few scientific papers, and almost none
| in top tier publications.
|
| What a colossal waste of money for so few results!
|
| Sorry to point out that the emperor has no clothes - I
| realize that HN is the home of scifi fanbois.
|
| (For example, prestigious publications have single-digit
| article counts, while ones I don't recognize have two-digit
| article counts. So almost all of the ISS papers were not
| high-quality enough to make it into a real journal, and
| divided by 21 years, most counts round off to zero. As I said
| - and I want my taxes back.)
| ahofmann wrote:
| From the article: "Meanwhile, the station's automated attitude
| control system had also noted [...]" A spelling mistake that
| immediately brings to mind The Hitchhiker's Guide to the Galaxy
| and the Heart of Gold :-)
|
| Edit: it seems that it is not a spelling mistake. "Attitude" has
| only one meaning to me, but "attitude control" seems to be a
| technical term that I've never heard of.
| krisoft wrote:
| "attitude" is the technical term in aerospace for the
| orientation of a vehicle.
| https://aviation.stackexchange.com/questions/35933/what-is-t...
|
| The instrument which shows how you are oriented is the attitude
| indicator: https://en.m.wikipedia.org/wiki/Attitude_indicator
|
| The piloting skill of turning an upset airplane to right side
| up is called "unusual attitude recovery":
| https://www.cfinotebook.net/notebook/maneuvers-and-procedure...
|
| It is quite an interesting topic. Whole books were written
| about it. "Fundamentals of Spacecraft Attitude Determination
| and Control" is one I can warmly recommend. But if you just
| want a one sentence summary: "use quaternions" seems to be the
| prevailing wisdom.
| alisonkisk wrote:
| Quaternions are a mathematical model. Are they also a
| mechanical solution?
| krisoft wrote:
| One can argue that the solution where they add a 4th gimbal
| to the stable platform to avoid the possibility of a gimbal
| lock is kinda-sorta a mechanical equivalent for a
| quaternion. See for example the famous exchange between
| CapCom and Apollo 11 Command Module Pilot Michael Collins:
| https://space.stackexchange.com/questions/30953/did-
| michael-...
|
| But when I wrote that really all I meant is that it is
| advised to use quaternions to represent the attitude
| information in the software which fills the gap between the
| sensors and the actuators.
| TMWNN wrote:
| >Edit: it seems that it is not a spelling mistake. "Attitude"
| has only one meaning to me, but "attitude control" seems to be
| a technical term that I've never heard of.
|
| Anyone not aware of the definition of "attitude" relative[1] to
| this discussion should shut up.
|
| [1] Pun intended, not that ahofmann would know
| aaronmdjones wrote:
| Where's the mistake? Attitude is the correct term.
| avnigo wrote:
| Attitude is a term in geometry:
|
| https://en.wikipedia.org/wiki/Orientation_(geometry)
| smarx007 wrote:
| ADCS is a well-known term, no spelling mistakes:
| https://ocw.mit.edu/courses/aeronautics-and-astronautics/16-...
| [deleted]
| foobarbecue wrote:
| Yeah... Maybe also figure out who drilled that hole!
| cududa wrote:
| If I remember correctly wasn't it an employee covering up a
| mistake, that to fully replace the damaged panel would've
| required disassembling/ rebuilding a large part of it from
| scratch?
|
| Edit: Ah, my mistake. Apparently some years prior that
| happened, but was caught before the Soyuz capsule launched. If
| the person responsible for that incident got disappeared, I
| could imagine whoever made that hole wanted to cover up any
| mistake
| kova12 wrote:
| It's probably the same guy who was trying to mount sensors
| upside-down, and they didn't fit, so he had to take out an old
| trusty drill
| toiletaccount wrote:
| well his job was to mount the damn sensors
| krisoft wrote:
| You are not wrong. :)
|
| This is one video of a launch failure which was eventually
| traced back to an upside down installed attitude sensor:
| https://youtu.be/ycRVAcZC5R4
| jacquesm wrote:
| At 27 seconds into that video you already know it won't
| end well.
| rkachowski wrote:
| What hole ?
| EdwardDiego wrote:
| Maybe this one? https://www.space.com/41738-soyuz-spacecraft-
| air-leak-hole-o...
| Mountain_Skies wrote:
| Regardless of who did it, that it happened at all is very
| worrying for the suitability of humans for long term living in
| space habitats.
| Robotbeat wrote:
| It is worrying for the state of the Russian aerospace
| industry. This has become a pattern.
| caconym_ wrote:
| The state of Russia's space program on the ground is not
| good. It's kind of shocking that they've managed to maintain
| the reliability of their Soyuz and ISS-related operations to
| date, more or less, but it was always just a matter of time
| until those things started unraveling too.
| lamontcg wrote:
| I don't understand how this incident, involving a Russian
| spacecraft, necessarily indicates that NASA now has a poor safety
| culture again. The argument seems to be missing a step.
| slowmovintarget wrote:
| Agree.
|
| The way the article is written you'd think this was NASA's
| station. How dare NASA let this happen!
|
| It doesn't belong to the US, it isn't NASA's station, it is the
| International Space Station. The module that tried to take its
| football and go home was Russian.
| alisonkisk wrote:
| The modules was latched to an American module.
|
| When your left arm decides to "go home" and your right arm
| doesn't, it's a problem for your right arm too.
| rhcom2 wrote:
| The article is criticizing what it sees as NASA's desire to
| go along with the Russians and just ignore it without a real
| investigation.
| figassis wrote:
| If all the US side has are flywheels to counter orientation
| issues, rather than thrusters, maybe costs are being cut where
| they should not?
| simonh wrote:
| It may be just down to the geometry of the station if the
| Russian sections are in the most efficient positions to mount
| the thrusters. Or maybe it's because you need to have a
| single control system in control of each system, one for the
| thrusters and one for the flywheels, and it's not viable to
| have those span the US and RU sections.
|
| In practice you need both systems. You can't just run up
| flywheels indefinitely, every now and then you need to use
| thrusters so you can spin them down. Meanwhile flywheels give
| you fine control that's difficult to achieve with thrusters,
| especially on something as big and complex as the station.
| dtgriscom wrote:
| Small quibble: the ISS gyroscopes are constant-speed; they
| apply torque to the station by pivoting their axes. The
| argument stands, though; if there's a constant need for
| torque then eventually the gyroscopes will end up all
| pointing in the same direction (a "singularity") and unable
| to apply further torque; thrusters will then be needed to
| balance the gyroscopes being returned to effective
| orientations.
|
| Ref: https://en.wikipedia.org/wiki/Control_moment_gyroscope
| suyjuris wrote:
| I found this very interesting, thank you for sharing!
| motoboi wrote:
| Just as no one carries a winch to counter their vehicle
| sudden backward acceleration. We just have turning wheels for
| normal day to day control.
|
| It's much more efficient just having a sane procedure to
| check which gear you are engaging.
| alisonkisk wrote:
| We have two kinds of brakes.
| greedo wrote:
| Actually, most cars have one type of brake, with two
| modes of activation.
| Denvercoder9 wrote:
| The ISS has always been designed as an integrated station of
| the Russian and US segment. There was never any need to
| duplicate functionality between both segments, as independent
| operation of each segment is non-goal.
| divbzero wrote:
| The core of the argument is in the response to the incident:
|
| > _To calm things down, official NASA spokesmen provided very
| preliminary underestimates in how big and how fast the station
| 's spin had been. These were presented without any caveat that
| the numbers were unverified--and the real figures turned out to
| be much worse. The Russian side, for its part, dismissed the
| attitude deviation as a routine bump in a normal process of
| automatic docking and proclaimed there would be no formal
| incident investigation, especially any that would involve their
| American partners. Indeed, both sides seemed to agree that the
| sooner the incident was forgotten, the better._
|
| The author, who worked in Mission Control operations in the
| 1980s, argues that similar signs of degrading safety standards
| and minimizing mistakes led up to the _Challenger_ tragedy.
| webreac wrote:
| Degrading safety is a very plausible explanation. Another one
| is that they know exactly what went wrong and they cover for
| each other because the mistake is so ridiculous that it would
| tarnish their reputation.
| alisonkisk wrote:
| That's the _same_ explanation, as thoroughly explained in
| the article -- politics is degrading and overriding safety.
| nickik wrote:
| I have long argued that dropping the Russians from this program
| is the only way to go.
|
| The Russians have turned into a hindrance. Every error that
| happens is a conspiracy. When one of their workers drilled a
| whole into their spacecraft they publicly accused Americans
| astronauts to be spies who sabotaged their hardware.
|
| Those who say 'but then they will work with China', ok, go ahead,
| destroy their space station. Let China finance their broken
| industry if they really want to.
|
| NASA needs to move on from ISS and move to a privately operated
| station with the main focus on the moon and Mars.
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