[HN Gopher] NASA mistakenly severs communication to Voyager 2
___________________________________________________________________
NASA mistakenly severs communication to Voyager 2
Author : belter
Score : 392 points
Date : 2023-07-31 10:15 UTC (12 hours ago)
(HTM) web link (www.theregister.com)
(TXT) w3m dump (www.theregister.com)
| [deleted]
| inopinatus wrote:
| That official statement seems incredibly light on detail, almost
| as if written for children, or worse, members of congress.
|
| I wonder, is there a technical publication elsewhere that has
| more substantial coverage for interested people?
| jjw1414 wrote:
| I expect that a technical publication will be available soon at
| one of these sources: https://voyager.jpl.nasa.gov/
| https://voyager.jpl.nasa.gov/mission/science/data-access/
| mark-r wrote:
| I'm amazed there was as much detail as there was. How do they
| know how far off the antenna is?
| lb1lf wrote:
| Presumably because that was the orientation the spacecraft
| was asked to get to before comms was lost.
|
| Also, it is possible that 2 degrees of misalignment still
| allows some fraction of the signal to be detected, but it not
| being strong enough to be decoded. The received signal
| strength and the beamwidth of the antenna could then be used
| to estimate how far off the mark the Voyager 2 dish is.
| bbarnett wrote:
| [flagged]
| tomca32 wrote:
| I honestly can't tell if this is satire or serious
| hutzlibu wrote:
| I lost that ability at some point during Covid.
| michaelt wrote:
| What more is there to say? It seems like a pretty clear
| explanation to me.
| [deleted]
| [deleted]
| inopinatus wrote:
| Well, congressman, I might be curious what the actual
| commands were, why they were issued, how it led to the
| unfavourable outcome, how they detected and measured the
| degree of misalignment, what a corrected command sequence
| might've been, and then cross-referenced to a hopefully
| existing article on how the spacecraft will eventually re-
| align itself, and perhaps some further reading on other
| commands that are routinely or not-so-routinely issued and
| how they are received, decoded, and executed on board the
| spacecraft. Basic stuff, y'know; after all, this isn't rocket
| science.
|
| If there is such an archive, or some approximation thereof,
| it would surely be fascinating to pore over it.
| jf22 wrote:
| I would not describe what you are asking for as "basic
| stuff."
| inopinatus wrote:
| Don't tell me this thing doesn't have a user manual.
| toomuchtodo wrote:
| FOIA it.
|
| EDIT: Reply here with a link to your Muckrock.com FOIA
| request and I'll send you the $5.
| tmpX7dMeXU wrote:
| [flagged]
| hfkwer wrote:
| Why would they owe you such detailed explanations? You're
| asking for a full-on incident report. These take days to
| write and there's no reason for the public at large to need
| it.
| ZiiS wrote:
| The is if they want the public at large to pay for it.
| guhidalg wrote:
| I guess you and I are being downvoted because people on
| HN can't tolerate engineers being questioned. Hey guys,
| everyone makes mistakes and it's an important part of
| scientific advancement to understand and _share_ that
| knowledge.
| josefx wrote:
| I am more interested in them working efficiently than
| wasting time writing a 50 page report every time someone
| drops a pen.
| bumby wrote:
| Ignoring the "pen dropping" strawman, how far does that
| trust go within the government?
|
| Do you want the military to "work efficiently" if that
| means little to no oversight? How about Congress?
|
| Oversight and accountability to the citizenry is a
| foundational principle in a functioning democracy.
| josefx wrote:
| > Ignoring the "pen dropping" strawman
|
| Saying that and then countering with your own.
|
| Yeah, the pen dropping is a bit over the top, but as of
| now the claim is that this situation is planed for and
| will resolve itself. A report now wont tell us anything
| of significance. It will get interesting if the
| realignment fails.
|
| > Oversight and accountability to the citizenry is a
| foundational principle in a functioning democracy.
|
| I don't see micromanagement in that list.
| bumby wrote:
| > _I don 't see micromanagement in that list._
|
| Is micromanaging what you're claiming is a strawman in my
| position? I'm not claiming you are saying the military
| doesn't need oversight, I'm probing with a concrete
| example where you draw the line on what constitutes a
| reasonable threshold of accountability. Note my
| statements were framed as questions to get clarification;
| that's not a strawman.
|
| Your micromanaging claim is however another strawman
| statement. I guess I could use clarification on your
| point. Your equating to micromanaging is misapplied IMO.
| "Micromanaging" would be a direct democratic vote on most
| or all issues, IMO. That's not what's being asked for
| here here. What seems to be asked for is transparency.
| Access to information is not the same as having authority
| to make all decisions. But it is paramount in a
| government when people elect representatives who make
| decisions (or appoint those who do). The big issue I'm
| asking is: where is the reasonable 'trust, no need to
| verify' stance when it comes to public/govt work? Can we
| just trust tens of millions of dollars on construction
| projects, but not when it gets to hundreds of millions?
| What about aerospace? Do we say it's fine to go ahead
| with limited accountability when it comes to billion-
| dollar robotic missions, but not when there's a safety-
| critical application?
|
| > _A report now wont tell us anything of significance._
|
| What makes you so confident? A report can tell us if
| processes were followed appropriately and, if not, if
| anyone was held accountable for not following them. I'd
| say that is pretty significant if you care about
| governmental fraud, waste, and abuse.
| dada78641 wrote:
| It's always a good thing for technical information about
| incidents like this to be made accessible to the public.
| NASA is a publicly funded organization and as such they
| do have a responsibility towards us.
|
| Of course there are operational details that we don't
| need to be made aware of, but for an incident as big as
| this there's no reason to at least know how it happened
| and what could be changed to prevent it from happening
| again.
| guhidalg wrote:
| Because I pay for NASA and I can ask for NASA to do a
| post-mortem.
| flangola7 wrote:
| [flagged]
| iLoveOncall wrote:
| I pay for NASA and I don't want them to spend needless
| resources releasing a public post-mortem. Talk about
| waste of resources.
| anigbrowl wrote:
| It definitely got written up internally. Making it public
| is just a matter of taking that, sticking it into a pdf,
| and hitting the publish button. A few hours' worth of
| additional work at most.
| birdyrooster wrote:
| Asking for a post mortem is not too much to ask. This is
| the bare minimum for operating serious craft like this.
| iLoveOncall wrote:
| There's a difference between a post-mortem and a public
| post-mortem. Nasa is pioneering technology that shouldn't
| all be public. If you really think the same post-mortem
| would be published in public and internally, you should
| not be commenting on HackerNews because it's forbidden
| below 13 years old.
| dabluecaboose wrote:
| As a spacecraft navigation engineer, I guarantee you said
| post-mortem is already being written, and is probably
| going to be posted "publicly" anyway on some deep corner
| of the NASA website
| rvnx wrote:
| This is the right call, let the people of the NASA focus
| on what is really important, and not waste time on PR.
|
| It's pretty obvious that the people who managed to extend
| the lifetime of Voyager are very smart, based on all the
| tricks they had to do.
|
| They are remotely configuring an old-tech device that is
| billions of kilometers away, with insane lag, and
| uncertainty that the underlying hardware is even
| responding properly.
|
| Absolutely anything could have gone wrong at this stage.
|
| They'll anyway investigate internally what happened, in
| order to hopefully, find a solution.
|
| There is no need to spend resources to make the material
| public, if the goal is mostly to satisfy curiosity
| (though it's interesting).
| bumby wrote:
| Does this assume the information is made available, but
| just not as polished as PR?
| ajb wrote:
| Normally this makes sense, because you're asking why
| money was wasted. But, in this case if it's permanently
| bricked you will actually save money, because if Voyager
| 2 is bricked the team working on it is now redundant.
| It's not like they had an incentive to be incompetent and
| waste money - very much the opposite.
| account42 wrote:
| You calculation only makes sense if you put zero value on
| operating a probe that far out in the galaxy - in which
| case you should be asking why there was a team working on
| it in the first place.
|
| But that value is not zero, and replacing it costs quite
| a bit - both money and time. Asking how and why this
| happened is a valid inquiry.
| ajb wrote:
| Under the assumption that it is bricked, the value is
| indeed now zero. I think where we differ is that you are
| assuming it will be replaced, but I don't think it will
| be. It's way past its design life so it was going to
| expire at some point.
|
| For science, I would want to do an enquiry anyway - I'm
| just commenting on the financial/accountability aspect.
| gottorf wrote:
| > Why would they owe
|
| > there's no reason for the public at large to need it
|
| As a member of said public, I would be curious to know.
| There's no need for taxpayer-funded agencies to operate
| in a cloak of darkness.
|
| Most everything done by government should by default be
| open to the public, with an exceedingly high bar that
| must be met to be otherwise. Otherwise, you run into
| nonsensical things like how some details around the
| assassination of a president 60 years ago are still
| classified on "national security" grounds.
| djur wrote:
| > As a member of said public, I would be curious to know.
| There's no need for taxpayer-funded agencies to operate
| in a cloak of darkness.
|
| This is what the Freedom of Information Act is for:
|
| https://www.nasa.gov/centers/armstrong/FOIA/request.html
|
| The report may not exist yet, so you may need to wait.
| MAGZine wrote:
| which of these is 'operating in a cloak of darkness':
|
| - NASA informs the public immediately, and then makes the
| details available later after they've had time to compile
| the news and information into a format useful for the
| public
|
| - NASA waits to inform the public until said report is
| finished
|
| or perhaps you're after option c:
|
| - NASA's network drives are open to the www in read-only
| mode, because, you know, 'open by default' entails
| realtime information (even though he doesn't actually
| care 99.9999% of the time. yet, someone should deliver
| this functionality, without it costing the taxpayer
| extra).
|
| NASA routinely makes a LOT of data open to the public.
| Like, you can get very detailed JWST data directly from
| NASA. Probably far more detailed than you'd ever care to,
| because NASA _does_ care about exactly your concern.
|
| Actually, many agencies publish very detailed data if you
| care to look.
| Dylan16807 wrote:
| "This is light on info but they're making a report
| later." would be a non-darkness answer.
|
| But do you have reason to believe they're working on a
| detailed public report?
|
| Because if they're not, then you missed option "NASA
| informs the public immediately, but never makes the
| details available" which would be unfortunate.
|
| Also they probably already answered a lot of these
| questions internally during the last week, so it wouldn't
| hurt to put some of that information out.
| kdmccormick wrote:
| I'm not here demanding an immediate report, but it _is_ a
| publicly-funded agency with a goal of furthering the
| world 's scientific understanding... and a detailed
| public writeup is not exactly a huge lift compared to all
| the other things they accomplish.
|
| I'm also the sort of person who thinks that all code
| written with public money should be open source.
| anigbrowl wrote:
| It's a public agency. The information is available by
| FOIA. Why not publish it upfront and save people the
| trouble?
| djur wrote:
| It takes time and effort to prepare such a document for
| public release. Government agencies produce all kinds of
| reports which are of minimal interest to the public.
| Making the documents available on demand via FOIA is a
| reasonable way to ensure that time and money isn't
| wasted.
| inopinatus wrote:
| Because I'm an annoyingly precocious child of thirteen
| and this is how you capture my interest and enable my
| future glittering career in deep space telemetry
| engineering.
| thefurdrake wrote:
| [flagged]
| hfkwer wrote:
| What a weird comment.
| thefurdrake wrote:
| What a weird response to having intellectual dishonesty
| being pointed out.
| jjk166 wrote:
| The context is a discussion of what explanations NASA
| owes in a brief public statement. Saying he'd like to
| know does not clearly denote that he is changing the
| parameters of the conversation to talk about something
| else.
| thefurdrake wrote:
| Please show me where this comment thread introduced the
| term "owed" before the one instance to which I replied.
| jjk166 wrote:
| That's not how language works. The conversation was over
| what information NASA was obligated to give, which is the
| definition of owed.
| thefurdrake wrote:
| Please show me which parts of the thread implied anything
| more than curiosity about what is being provided, since
| you're dodging the point.
| jjk166 wrote:
| > That official statement seems incredibly light on
| detail
|
| They are complaining about the official statement,
| specifically its lightness on detail.
| thefurdrake wrote:
| Ah, so you're equating mild dissatisfaction (and truly,
| it is incredibly mild, that's some beige entitlement
| alright) with demand and a sense of entitlement. I see
| what went wrong now! Thank you.
| inopinatus wrote:
| As the ultimate progenitor of this tangent I hereby
| validate _thefurdrake_ 's interpretation. My remarks were
| intentionally worded to form an inquiring statement of
| observations and preferences, not a demand for action on
| the basis of obligation, and the attempt to derive an
| unstated and unintended sentiment of vituperative
| entitlement is, indeed, gross.
|
| The unsubtle misparaphrasing of Mark Twain was included
| as a comedic flourish to provide a light-hearted framing
| of the comments, but upon review of the subsequent
| debate, I concede it's possible that for some, any
| allusion to statecraft stimulates the adversarial lobes.
| bitcharmer wrote:
| Jesus, I bet you're also one of those people that are
| fine with mass surveillance because it's ok because your
| have nothing to hide. It's people like you who set the
| bar so low that we can't have nice things. Sheesh
| gpvos wrote:
| Except that it actually _is_ rocket science.
| nocoiner wrote:
| "Mistakes were made." Between that and "I have no
| recollection," that's probably as far as any congressional
| hearing would be able to drill into this.
| idlewords wrote:
| This is why you always have a backup Voyager
| samhuk wrote:
| TL;DR:
|
| 1. Voyager 2 has been pointing 2 degrees off from Earth
|
| 2. Been that way for a while and nobody noticed because very old
| computers.
|
| 3. Meaning that the probe has gone dark (ingress and egress comms
| are not possible)
|
| 4. However, both Voyager probes have software that tells them to
| routinely calibrate themselves every few months
|
| 5. Meaning that it should point at Earth in the next few months
| (most likely).
| jannyfer wrote:
| I don't think the article or the news release from NASA
| actually says #2. They could have known for a week but took a
| week to release the news.
| iszomer wrote:
| > 5. Meaning that it should point at Earth in the next few
| months (most likely).
|
| Provided that V2 still has enough propellent to make this
| adjustment.
| Qem wrote:
| Can we also regain contact through the yearly movement of Earth
| on its orbit? Like the planet just walking into the new beam
| position?
| [deleted]
| ummonk wrote:
| The Earth is only about 150 million km (1 AU) from the sun,
| so nope the Earth can't move far enough to make up for a 2
| degree miss from 32 billion km away, even if it's in the
| right direction.
| OnACoffeeBreak wrote:
| Wouldn't work if the 2 degrees is not in the orbital plane of
| Earth. Right?
| samhuk wrote:
| No. 2 degrees error at such a large distance equals _huge_
| distance error.
|
| Also, empty space is huge and matter-things like Earth and
| the Sun are tiny compared to it.
| somenameforme wrote:
| I think we can answer this exactly. To visualize this think
| about the plane shared by the satellite and Earth. We'll
| imagine this as a 2D unit circle. In this graph Earth is at
| (1,0) and the satellite is at (0,0). So we end up with a
| scale where the radius is the same as the distance from the
| Earth to the satellite. But instead of pointing at (1,0), the
| satellite is now pointing at (cos(2), sin(2)) or (0.9994,
| 0.0349).
|
| The distance from Earth (1,0) to the new location (0.9994,
| 0.0349) is about 0.0349. We need to scale that back up to
| "real" units so multiplying it by 15 billion miles. And we
| get about 520 million miles. The earth is about 93 million
| miles from the Sun, so its max positional shift (under
| extremely improbable absolutely perfect conditions) would be
| ~180 million miles.
|
| So there's no way we could regain contact with just yearly
| movement, even before we account for the fact that it's
| getting further and further away. 2 degrees intuitively
| sounds small, but on an astronomical scale it's _huge_ and
| this sounds like a pretty major flub by NASA.
| Qem wrote:
| Great explanation. Thank you!
| [deleted]
| 5d41402abc4b wrote:
| Are communications with voyager encrypted? Is it possible for
| someone to setup a big antenna in their backyard and take over
| the probe?
| qingcharles wrote:
| These guys[1] hacked a NASA space probe and refired its motors.
| I read the entire blog once but I can't remember if there was
| any sort of encryption on the communication, although I know
| that was brought up. Modern probes do use cryptography, but I
| doubt Voyager does. I suspect if you fired commands at it you
| could control it. For the lulz or whatever.
|
| [1]
| https://en.wikipedia.org/wiki/International_Cometary_Explore...
| yonatan8070 wrote:
| I don't think there's any encryption going on there, just
| because it's so old
|
| But I also don't think most back yards can fit an antenna that
| big... search "NASA deep space network" on google images to get
| a scale of the antennas that are used to talk to voyager
| arbuge wrote:
| It doesn't matter how big your antenna is if Voyager's antenna
| is no longer facing earth, as seems to have been accidentally
| induced here.
| bell-cot wrote:
| Untrue, strictly speaking. So long as the combination of your
| transmitter's power and your antenna's directionality (aka
| 'gain') provide enough extra dB's of signal strength (to
| compensate for the dB's "lost" on Voyager's end, due to the
| off-axis antenna) it'll work fine.
|
| OTOH, dB's are effectively a log scale, and NASA's "not good
| enough now" transmitter & antenna cost quite a few $million.
| What's your budget?
|
| (Yeah - if the Arecibo radio telescope was still on
| operation, it might well have been capable of doing this.)
| guraf wrote:
| I suspect it is true, strictly speaking.
|
| In optimal orientation, Voyager's signal peaks at -160dBm
| when received on the 70m dishes. Now it's shooting 2
| degrees off which means the signal misses earth by hundreds
| of millions of kilometres. What kind of magical high gain
| antenna do you envision that could still receive it,
| assuming money isn't a problem?
| bell-cot wrote:
| Voyager 2 has a direction radio antenna, not a laser
| producing a sharp-edged beam.
|
| https://en.wikipedia.org/wiki/Voyager_2#Communications
|
| https://en.wikipedia.org/wiki/Parabolic_antenna#Beamwidth
|
| How about this antenna?
| https://en.wikipedia.org/wiki/Very_Large_Array
|
| Or this one? https://en.wikipedia.org/wiki/Five-hundred-
| meter_Aperture_Sp...
| whartung wrote:
| "Encrypted". That's really funny.
|
| A favorite anecdote of Voyager.
|
| Paraphrasing, "You carry around more computing power in your
| pocket than what is on Voyager. I'm not talking about your
| phone, I'm talking about your key fob".
|
| The data Golay encoded, but not encrypted. That's exhausting
| enough for the 1/2 dozen NAND gates up there that make up its
| computer.
| palijer wrote:
| If someone sets up an antenna in their backyard to accurately
| transmit and receive signals 32 billion km away, I'm willing to
| bet NASA would gladly trade old probes for that scientific
| breakthrough of the century.
| db48x wrote:
| Their HOA would be _really_ mad.
| helsinkiandrew wrote:
| A 70 metre antenna with enough control to point in the right
| direction. As voyagers batteries are meant to die in a couple
| of years, there's probably more interesting things to do with
| your money.
|
| https://voyager.jpl.nasa.gov/news/details.php?article_id=118
| qingcharles wrote:
| If you want to decode the downlink of a more recent probe,
| here's the details (apparently NASA don't have the source code
| for the decoder, but a binary was found):
|
| https://skyriddles.wordpress.com/2023/07/03/stereo-a-comes-h...
| kyberias wrote:
| I find it hilarious that they're refering to the speed of the
| spacecraft.
| starkparker wrote:
| Jon Bois is probably livid and/or excited
| syndicatedjelly wrote:
| I too know what this reference is
| mark-r wrote:
| "Voyager 2's trajectory is expected to remain unchanged" - I
| should hope so! There can't be any fuel left on board that would
| budge it, even if they wanted to.
| [deleted]
| padjo wrote:
| Hope the re-calibration works. Would be a sad way to lose contact
| after all these years.
| midoridensha wrote:
| True, but they only had enough power on-board for it to last
| until 2025 anyway, so it's already on its last legs.
| albert_e wrote:
| The power needs are mainly for radio communications back
| home?
|
| Or that includes navigation / propulsion / course corrections
| / reorientation also?
|
| (There is not enough "solar power" that can be harvested at
| that distance I presume)
|
| If we spread out the communications to be less frequent and
| say bring it down to essentially a heartbeat signal once a
| month ..would it prolong the service life. Mostly for
| emotional reasons at that point :)
| whaleofatw2022 wrote:
| The 'battery' in this case is an RTG, so the amount of
| power drops whether it is used or not.
| phire wrote:
| It might be possible to use the remaining electrical
| heaters as some kind of crude thermal battery (assuming
| they have any heaters still running, they already shut
| down the heaters for most of the scientific experiments).
|
| Simply turn the heaters off before transmitting and keep
| any transmission periods short enough that the
| electronics don't get too cold.
|
| JPL probably have a bunch of tricks like this ready for
| when power levels drop. That 2025 estimate is 10 years
| old and I'd be surprised if it's final.
| jffry wrote:
| Voyager 2 is approximately 20 billion km from the Sun
|
| Earth is approximately 150 million km from the Sun
|
| Sunlight intensity falls off with the square of distance
| (ignoring any additional small losses from space dust /
| scattering from gases etc), so twice the distance = a
| quarter the solar flux. At the Earth it's ~1361 watts per
| square meter.
|
| Voyager 2 is approximately 133 times further from the Sun
| than Earth is, which means it receives optimistically 1361
| / (133^2) = 0.07694 watts per square meter.
|
| I found a JPL article [1] that says the RTG onboard Voyager
| produces 40% less power than it did at launch, and the
| Wikipedia article [2] says it produced 470W at launch,
| which means it makes ~280W now.
|
| Wikipedia [3] suggests the solar panels available at the
| time of Voyager's launch in the late 1970s could convert
| ~10% of incoming solar power to electricity. Modern panels
| bring that up to 30% but the designers of Voyager did not
| have access to time travel.
|
| So at present distance Voyager would need approximately
| 36000 square meters of solar panel to produce the same
| amount of power.
|
| [1] https://www.jpl.nasa.gov/news/a-new-plan-for-keeping-
| nasas-o...
|
| [2] https://en.wikipedia.org/wiki/Voyager_2#Power
|
| [3] https://en.wikipedia.org/wiki/Solar_panels_on_spacecraf
| t#His...
| bee_rider wrote:
| There have already been some questionable football field
| size comparisons in this discussion thread, but in this
| case the comparison might add intuition--that is about 7
| American football fields worth of solar panels.
| jabart wrote:
| They made some updates and expect it to go through 2026
|
| https://voyager.jpl.nasa.gov/news/details.php?article_id=129
| beeforpork wrote:
| It will probably readjust. And power supply is expected to be
| dead ca. 2025 anyway.
|
| OK, OK, if the Klingons find it _now_ , then it'd be a shame not
| to get some measurements. (The cameras, however, are off since
| decades.)
| foobarbecue wrote:
| Let's just hope it doesn't make it to the machine planet.
| teddyh wrote:
| That's Voyager 6, not Voyager 2.
| zelphirkalt wrote:
| This seems like a multi-reference to me:
|
| (1) Dune, (2) Turrican, others?
| WorldMaker wrote:
| Most directly in the context of Star Trek (Klingons
| mentioned above), it will be a reference to Star Trek: The
| Motion Picture. (Which is about the hypothetical Voyager 6
| probe's interesting history.)
| jabart wrote:
| They made some updates and expect it to go through 2026
|
| https://voyager.jpl.nasa.gov/news/details.php?article_id=129
| tivert wrote:
| >> It will probably readjust. And power supply is expected to
| be dead ca. 2025 anyway.
|
| > Are you both misunderstanding that? Your link says:
|
| > Launched in 1977, the Voyager 2 spacecraft is more than 12
| billion miles (20 billion kilometers) from Earth, using five
| science instruments to study interstellar space. To help keep
| those instruments operating despite a diminishing power
| supply, the aging spacecraft has begun using a small
| reservoir of backup power set aside as part of an onboard
| safety mechanism. The move will enable the mission to
| postpone shutting down a science instrument until 2026,
| rather than this year.
|
| > Switching off a science instrument will not end the
| mission. After shutting off the one instrument in 2026, the
| probe will continue to operate four science instruments until
| the declining power supply requires another to be turned off.
| If Voyager 2 remains healthy, the engineering team
| anticipates the mission could potentially continue for years
| to come.
|
| Going from 5 science instruments to 4 in 2026 is hardly
| "dead."
| llacb47 wrote:
| extra > on 2nd line
| utopcell wrote:
| So, until Oct/15, some poor planet with intelligent life in our
| galaxy will be thinking that an alien civilization is trying to
| make contact.
| ChrisArchitect wrote:
| Official blog post from a few days ago:
|
| https://news.ycombinator.com/item?id=36909736
| moron4hire wrote:
| At 32 billion kilometers distance, 2deg off target means the
| communication beam is missing Earth by about 1.1 billion
| kilometers.
|
| EDIT: This is about 7.4AU. If Jupiter and Saturn were in a line
| from Earth right now, this distance from Earth would be about the
| halfway point between the two gas giants. So no, we also won't be
| launching a rocket to go catch the beam just to re-establish
| comms.
| danbruc wrote:
| Just two degrees off? Can they not wiggle the antenna a bit
| around [1] just as in the old days when you had to hold the TV
| antenna a bit above the TV to see anything but noise?
|
| [1] Joking aside, they obviously can not, Voyager is missing the
| Earth by 4.5 AE. How wide is the beam, how precisely do they have
| to aim the antenna to maintain communication?
| drmpeg wrote:
| The beam width is 0.65deg at x-band. If it's off pointed by
| 0.5deg, the signal will be 7 dB lower (which in this case, is a
| lot).
| notyourwork wrote:
| Every time I read about space engineering, I'm amazed by how
| contingencies have contingencies. It's so much careful planning
| and rigor compared to my world. I can always re-compile, re-
| deploy and regularly realize that my job is not life or death.
| Enginerrrd wrote:
| Honestly, I'd say most engineering is like that outside of the
| software world. In the classic engineering disciplines with
| actual licensures at the end of the pipeline, the
| responsibility and ethics of this are ingrained into students
| from day 1. (Budget and importance of the application doesn't
| always allow for the indulgence of this though, at least to a
| point.)
|
| This type of thinking also follows from decades of experience.
|
| For some reason the software engineering world largely
| abandoned esteem and respect for all of the above.
| bee_rider wrote:
| I did an engineering degree but I have to say, the ethics
| imparted on me were basically "be diligent and don't build
| anything that harms people by accident" which... really ought
| to be, like, table stakes for living in society, right?
| 1123581321 wrote:
| As you've stated the oath, it's certainly glib, but it's
| not table stakes because it's not a mere commitment to good
| intentions or a kind heart. Engineering ethics are not a
| commitment to good intentions. To take that pledge
| seriously, you need to be able to trace all your
| requirements and consequences in order to analyze, prevent
| and verify you've prevented potential danger without
| breaking what you've built. Most people in society would
| not succeed at this.
| throwawaysleep wrote:
| Errors in software rarely ever matter and even when they do,
| can usually be trivially corrected.
| programzeta wrote:
| It's not life or death, but time spent dealing with errors
| - debugging, the direct effects, understanding full impact
| - isn't a resource we can get back.
| wizofaus wrote:
| I find myself thinking about that a lot - mainly "how
| many more hours would have needed to be spent at stage A
| to avoid the hours being spent now to recover from
| problems our software is currently causing". And often if
| I'm honest with myself it's hard to see that the extra
| investment of time earlier on would have necessarily
| resulted in a net productivity gain. It would however
| likely be a less stressful way to work (building fire-
| proof code rather than putting fires out all the time),
| and rather more satisfying. As an engineer of any sort I
| think it's perfectly reasonable and justifiable to want
| to produce something of quality even if it takes longer
| and the consequences probably won't be that terrible if
| you just release the first thing you can slap together.
| Unfortunately others are almost entirely motivated by the
| (not entirely irrational) fear of what happens if you
| don't release something quickly enough.
| BossingAround wrote:
| It's funny you say that, because designing systems that
| work extremely well, have contingencies upon
| contingencies, and can be relied upon (e.g. as a life-
| critical system) is so time consuming and (I imagine)
| mind numbingly boring (e.g. reviews upon reviews of white
| papers to ensure that the system spec is scientifically
| sound) that I'd guess time is the last thing you'd get
| back from writing NASA-style applications.
| crooked-v wrote:
| Except when they do matter, like the Therac-25 deaths or
| those 737 MAX crashes.
| nawgz wrote:
| > 737 MAX crashes
|
| To imply this was a software bug is a pretty silly
| representation - the system was poorly engineered and
| didn't have proper contingencies for sensor disagreement.
| This is pretty clearly a design/engineering error with a
| software component.
|
| Besides, the guy said "rarely ever matter" for a reason,
| not "explicitly never impact things"... Bit of a silly
| comment from you IMO
| bumby wrote:
| To view software in isolation is an equally silly
| representation. In the physical world, software is part
| of an overall system that needs to be considered
| holistically. Most major safety-critical mishaps are the
| result of several failures, often across different
| domains.
|
| In the case of the 737MAX, the software was a design
| around a physical constraint; that doesn't mean the
| software doesn't matter. Most software is designed as a
| workaround of a certain physical or mental constraint.
| BossingAround wrote:
| If you're referring to MCAS in 737, the software itself
| wasn't the main problem; I'd say that the main problem
| was that it wasn't even a documented feature (let alone
| the engineering of the system itself).
|
| The pilot couldn't even turn MCAS off originally. That's
| not a software thing, that's a "who the F designed this"
| thing.
| cratermoon wrote:
| Honestly I can't imagine someone who hasn't been living
| under a rock for the last half century could say this. Just
| one example: Knight Capitol was the largest trader in U.S.
| equities, with a market share of 17.3% on NYSE and 16.9% on
| NASDAQ in 2012, right up until August 1, 2012, when it lost
| $460 million and 75% of its equity value because of a
| software error. What was left of it was acquired in
| December of that year.
| bumby wrote:
| Software does not wear out like most physical components,
| but they often cause failure in interaction/coordinating
| between subsystems.
|
| As the amount of coordination increases, the number of
| failure modes tends to grow quite fast. That's why software
| failures in physical, safety-critical systems are not
| trivially corrected. There are a lot of second order
| effects that need to be considered.
| Qem wrote:
| > Software does not wear out like most physical
| components.
|
| It fails like buildings near fault lines, because the
| ground moves under them. Think broken dependencies,
| operating system obsolescence, et cetera.
| bumby wrote:
| I like this analogy. Although your example focused on
| software-centric coordination, I think it's important to
| also extend it to non-software systems.
|
| An apropos and famous example is the Ariane 5 rocket
| mishap. The same validated software from the Ariane 4 was
| used, but the hardware design changed. Specifically, the
| velocity of the Ariane 5 exceeded that of its predecessor
| and exceeded the 16-bit variable used.
| furyofantares wrote:
| > For some reason the software engineering world largely
| abandoned esteem and respect for all of the above.
|
| The main contingency with most software is that you fix it.
| thrashh wrote:
| It's not the licensing or the ethics classes or the
| responsible thinking or the professors that causes some
| engineering disciplines to be more carful.
|
| It's the cost when something fucks up.
|
| If I'm holding my phone near a cliff, and I rely on it for
| navigation and I'm hours from civilization, I'm a little more
| careful, not because I'm normally super careful. It's because
| -- in that specific scenario -- losing my phone would cost me
| so much and the chance of it happening is much more likely.
|
| Space companies spend a little extra because the cost is
| years of development and billions of dollar evaporating in a
| few seconds.
|
| And there are software teams in certain industries that dot
| their I's and cross their T's as well.
|
| Even on some dumb CRUD app, if it's a critical piece of code
| that the rest of the software hinges upon, you spend a little
| extra time because the cost of fuck up is so major.
|
| Or you're launching a product and you have a sign up that
| will seed your user base, you damn well make sure it works.
| NBJack wrote:
| To be honest with ourselves, until we have standardized
| licensing/accreditation that is fully recognized, we aren't
| really engineers.
|
| I would love to see a day when redundancy like this is just a
| standardized, accepted practice rather than a stand-up
| debate. Easier said than done of course.
| e1g wrote:
| You can have this now, just go work in healthcare tech or a
| bank. The trade off is no innovation, career boosts,
| professional accomplishments, or projects under $10M.
|
| Clients who want NASA quality can have it if they bring
| NASA budgets and timelines.
| alex_lav wrote:
| Move Fast And Break Things^TM
|
| Jokes aside I think it's mostly a value/cost thing. NASA's
| software has different requirements and failure scenarios
| than most software developers (in this context I will not
| call them software engineers) have to care about. Verifiable
| correctness is harder to predict, and in most devs' roles
| it's easier to just try something and see what happens,
| rather than know what'll happen up front.
| Tade0 wrote:
| > Honestly, I'd say most engineering is like that outside of
| the software world.
|
| Add civil engineering to that nowadays - both buildings and
| roads.
|
| Sure, there are regulations and licensing, but quite often
| the entity financing the whole thing cares little about such
| things.
| bilalq wrote:
| I don't understand why this dig is constantly taken at
| software. Look at how many layers of fallbacks exist even on
| the average webapp written by junior devs. Optimistic
| rendering on form submissions, graceful degradation of
| features, falling back to last cached data, HTTP request
| retries with binomial exponential backoff and jitter, TCP
| packet retransmits, ECC corrections on servers, etc.
|
| In cases where fault tolerance isn't as robust, it's for the
| same reasons as other disciplines you mentioned: budget and
| importance.
| MrJohz wrote:
| It's also completely untrue that the norm outside of
| software engineering, I think this perception comes because
| we only think of the big engineering projects like NASA or
| building projects, and forget how broad engineering is and
| can be. I worked for a company that mainly did electrical
| engineering, and there was plenty of happy-path work that
| just assumed the error cases would happen rarely or be
| handled somewhere else. It was also quite difficult to get
| good change control working, and automated testing was
| painful and irregular. (In fairness, automated testing was
| also a lot harder, but we could have worked harder on it
| and caught a lot more issues early on.)
|
| My impression from friends working in other engineering
| disciplines is that software engineering works similarly to
| other fields: the more risk to human lives is involved, the
| more testing, redundancy, etc is involved.
| dfex wrote:
| I think it comes down to to a couple of things that
| software doesn't have that most other disciplines do:
|
| Standardisation - in the big 'E' Engineering world, there
| would be a recognised international standard for Web Apps
| that ensured/enforced that all Web Apps supported this
| functionality, or they would not be approved for use.
|
| Another factor is Accountability. A senior Software
| 'Engineer' would have to take personal responsibility
| (liability, accountability) that the software product they
| are producing and/or overseeing met all these requirements
| and personally sign off that these standards have been met.
| If the product were to fail at any point and it was
| determined that the cause was negligence in following the
| standard, any damages sought (not common, but not unheard
| of) would ultimately find their way to the accountable
| individual and their insurance.
|
| In cases where budgets/importance don't allow for this
| level of scrutiny, there would still be paperwork signed by
| the producer of the software and the client acknowledging
| deviation from the standard and waiving any recourse for
| doing so.
| Enginerrrd wrote:
| I agree with this 100%.
| swozey wrote:
| I like when people mention that they're "computer doctors." I
| have some stressful migrations that require a lot of planning
| and could cost a significant amount money if botched but I
| can't imagine the additional stress of someones life being at
| my fingertips.
| NikolaNovak wrote:
| It's tricky.
|
| Many moons ago when I was hands-on and stressed about
| migrations & config, my team lead at the time would say
| exactly the same thing - his wife is a doctor and her job is
| way more stressful - People die. And I bought into it as a
| relief for a while.
|
| But... I work on a payroll system. My team does _impact_
| people. Mistakes can have important negative consequences to
| real live individuals - from stress invoked in trying to call
| help centre and fix their paycheques, to disconnected
| utilities if they don 't get paid correctly/timely, to other
| downstream consequences.
|
| Any number of other IT systems have significant consequences
| - e.g. airline ticket systems, airbnb bookings, etc. I feel
| the "nobody died" is a double-edged sword: it can help
| relieve people of the daily sense of artificial stress,
| urgency and grind that management may impose; but also builds
| a false dichotomy / unreasonably binary threshold on when our
| job matters / impacts ...
| whatshisface wrote:
| I think one of the greatest contributions launch window
| aerospace neurosurgeons make to society is the way they
| cause nobody else to ever feel stress in any way.
| mcguire wrote:
| https://en.wikipedia.org/wiki/List_of_data_breaches
| noughtnaut wrote:
| > "the antenna on the spacecraft had been pointing two degrees
| away from the Earth [...] left it without the ability to receive
| commands or transmit data [...] NASA reckons the situation is
| temporary [...]"
|
| I wonder how it's temporary. Does the probe have a re-targeting
| function? The answer is in the original statement:
|
| > "Voyager 2 is programmed to reset its orientation multiple
| times each year to keep its antenna pointing at Earth; the next
| reset will occur on Oct. 15, which should enable communication to
| resume. The mission team expects Voyager 2 to remain on its
| planned trajectory during the quiet period."
| williamdclt wrote:
| I wonder why the reorientation is so infrequent? Is it a long
| process or a strain on hardware that you wouldn't want it to
| happen every day or even every month?
| rvnx wrote:
| It costs fuel to reorientate
| csunbird wrote:
| In addition to the points made by sibling comments, there is
| always a chance something going wrong in the reorientation,
| so you do not want to do this more than necessary
| Dalewyn wrote:
| Reorienting requires using a reaction wheel or propellent to
| move yourself.
|
| Propellent is finite, so you want to use it as rarely as
| possible.
|
| A reaction wheel is by itself infinite (assuming it doesn't
| break), but eventually it saturates and you need to
| desaturate it, which basically means spinning the wheel the
| other way while spending propellent to maintain position.
|
| All of this is to say, reorientation is an expensive process
| especially if refueling isn't an option.
| Dylan16807 wrote:
| Reaction wheels only saturate by absorbing external
| acceleration, though.
|
| You can reorient as much as you want with a reaction wheel,
| and the only cost is electricity.
| curiousObject wrote:
| > _reorientation is an expensive process_
|
| That's true, but a failsafe automatic reorientation mode
| after two weeks with no communication from Earth might be a
| useful feature
| jjk166 wrote:
| On the timescale of decades, does a 2 week vs a 10 week
| waiting period make much of a difference?
| qingcharles wrote:
| Does NASA have any sort of emulator to test commands against
| before they run them on live?
|
| I mean, we're all human, I've made some really shitty fatal
| errors hacking untested code onto production servers.
| mcguire wrote:
| It's hard to find anything about older programs, but they
| currently put a lot of work into simulators.
|
| https://www.nasa.gov/sites/default/files/ivv_grubb_nasa_ivv_...
|
| On the other hand, at one time there was a physical "proof test
| model" of the Voyagers.
|
| https://www.jpl.nasa.gov/images/pia21734-voyager-test-model-...
| albert_e wrote:
| > it is programmed to recalibrate its position a few times a
| year. October 15 is the next scheduled reset.
|
| Curious to know how this recalibration actually works. Any
| explainer that anyone can point to would be appreciated. Thanks!
| ZiiS wrote:
| Not a rocket scientist; but I have tuned in a TV. I imagine it
| is simply programed to turn a few degrees then turn back to
| wherever it saw the strongest signal from earth.
| j16sdiz wrote:
| But....How does it know it's the earth?
|
| It is billions km away.., is the earth _that_ noisy compare
| to solar wind and cosmic rays?
| giantrobot wrote:
| Voyager has a star sensor that is meant to align with the
| Sun and Canopus (IIRC). If both are properly aligned it
| means it's pointed in the right direction. At its current
| distance the beam width is wide enough to cover all of
| Earth's orbit. So really it just needs to point at the Sun
| anymore.
|
| The carrier signal from Earth is also powerful on a
| particular frequency and polarization. While there's
| definitely noise at the receiver it's looking for a very
| specific signal so can filter out everything it's not
| expecting. We do the same thing on the Earth side,
| filtering out noise to recover the very weak signal
| received from Voyager.
| albert_e wrote:
| Makes sense.
|
| So I presume it uses its thrusters to impart a very small
| spin on one axis, and then on an orthogonal axis.
|
| A mechanism records the signal strength as it sweeps all
| angles, and once the optimum direction is determined, the
| thrusters are fired in just the right way to counteract the
| spin and bring the craft to a halt at the optimum
| orientation.
|
| Given this was programmed decades ago - the electromechanical
| system that does all this jugglery and runs reliably for so
| long would be a great case study for systems design.
|
| Even the programming that ensures that this routine is
| triggered without fail every few months must also have gone
| through intense reliability testing.
| ilyt wrote:
| doesn't even need thrusters if it has reaction wheels that
| are still operational
| JdeBP wrote:
| Start at the Voyager book at
| https://descanso.jpl.nasa.gov/DPSummary/summary.html .
| albert_e wrote:
| Excellent link - thanks
|
| I skimmed though the Voyager document and it seems to have
| very good coverage of overall telecommunications system.
|
| For the topic of the periodic calibration the following is
| all I could spot
|
| >> Four 7-hour and two 0.5-hour attitude control calibration
| maneuvers are performed per spacecraft every year, each
| requiring 70-m station downlink coverage to ensure
| uninterrupted downlink telemetry.
|
| While this is interesting in itself, it merely states the
| schedule but doesn't satisfy my curiosity about the exact
| mechanism used to do the recalibration.
|
| Thanks nevertheless. Interesting reads here.
| JdeBP wrote:
| The Voyager Neptune Travel Guide mentions things like the
| Canopus Star Tracker and the Sun Sensor.
|
| https://ntrs.nasa.gov/citations/19900004096
| albert_e wrote:
| Thanks!
| sqrt_1 wrote:
| Good video on the topic - there is a sun sensor on the dish -
| looks for the brightest object and orients to face it.
| https://www.youtube.com/watch?v=NbsHgE89qO4&t=340s
| superb_dev wrote:
| For all the distance Voyager has covered, our Sun is still
| the brightest object in its view? That's incredible
| Rebelgecko wrote:
| The space between stars is truly immense. The sun is still
| 2,000 times closer to Voyager 2 than the next star
| BenjiWiebe wrote:
| Approx one light-day out. The nearest star is 4.2 light-
| years out.
|
| Doesn't even matter if voyager is heading towards it or
| not, it's still crazy far away. Voyager is still on our
| doorstep as far as interstellar distances go.
| qingcharles wrote:
| How bright does the Sun appear compared to other stars at a
| distance of 32Bn km?
|
| Here is a photo from Voyager 1 at a distance of 4Bn miles:
|
| https://photojournal.jpl.nasa.gov/catalog/PIA00450
| albert_e wrote:
| Superb! Thanks for the link.
| Out_of_Characte wrote:
| Does anyone know how Voyager calibrates their antennas?
| NeoTar wrote:
| Not in any detail, but as a hand-waving explanation it keeps
| tracks of the Sun and the star Canopus, so by two fixed
| reference points you can have a known orientation.
| potamic wrote:
| I can't even begin to imagine how you would go about building
| an automated star tracker in the 60s.
| jjk166 wrote:
| The Sun is the brightest star and Canopus is the third
| brightest star (Sirius presumably is not in an appropriate
| position to be detected), so you don't really need a proper
| star tracker, you just need a brightness sensor.
| whartung wrote:
| But the ICBMs did. They also had star trackers to help
| them navigate, and they needed more robust maps than just
| the Sun and Canopus, since they had to be able to fly
| 24hrs a day, 365 days a year. Different problem space.
| makomk wrote:
| There's a bunch of publicly available documentation about
| how the Canopus star tracker on the Voyager probes works
| out there, last I looked, and it's quite an interesting
| design by modern standards. It uses an image dissector
| tube, which is weird and long obsolete vacuum tube tech
| that can measure the light in an electronically-controlled
| section of an image, to scan a slice of the sky around the
| roll axis of the spacecraft looking for an area in the
| right intensity range (which is fairly easy for Canopus
| since it's generally the brightest thing in that part of
| the spacecraft's view so long as the roll axis is correctly
| aimed at the Sun), and there's a bunch of hardwired digital
| electronics to control it and use that to adjust the
| spacecraft orientation.
| bradgessler wrote:
| This will make for the ultimate "that time I brought down
| production" story for the engineers involved in this oversight.
| KenArrari wrote:
| aliens
| hutzlibu wrote:
| In short, it was remote bricked, by giving it commands to rotate
| a bit. After successfully executing those commands - no further
| commands could be received, as now the antennas are not facing
| earth anymore.
|
| But luckily it automatically readjust itself to earth
| automatically every half year exactly for these events. So on
| 15.10 we will know, if it is really lost. In either case, the end
| of its mission is near anyway, because the nuclear batteries are
| near its end.
|
| edit: Nasa has a blog post on this
| https://blogs.nasa.gov/sunspot/2023/07/28/mission-update-voy...
| datadeft wrote:
| > because the nuclear batteries are near its end.
|
| and we are charging our phones daily....
| Inityx wrote:
| https://youtu.be/NT8-b5YEyjo
| WalterBright wrote:
| Perhaps a better design would be to realign the antenna
| automatically if it hasn't received any signal from Earth after
| a week or whatever.
| jonny_eh wrote:
| We can certainly do that with Voyager 3!
| politelemon wrote:
| This link from NASA mentions the October 15 date:
|
| https://www.jpl.nasa.gov/news/nasa-mission-update-voyager-2-...
| hutzlibu wrote:
| The text and link I provided mention it as well, but I am now
| not sure, if giving 15.10 as a date was maybe confusing for
| non europeans (or non germans, I am a bit lost who uses what
| date format)...
| guraf wrote:
| It was confusing to me. Took me a while to realize it was a
| date and then had to deduce what it represented.
|
| Frankly before your comment I wasn't going to complain
| because I saw the tantrum you threw when people corrected
| you on the usage of "bricked" but maybe next time spell the
| month to avoid ambiguity.
| madacol wrote:
| Oh man that reminds me a lot to Kerbal Space Program, those
| times I lost communication because of a wrong turn and the
| antenna/solar panel faced the wrong way
| NBJack wrote:
| I like to think at least a few NASA engineers come to
| meetings with some brilliant ideas....that were cooked up at
| the 1am mark of a 7 hour weekend KSP binge.
| jojobas wrote:
| You have to agree that "skip to morning" button really
| works.
| mromanuk wrote:
| who and when was this automatic reset on 15.10 added?
| dylan604 wrote:
| reminds me of the time I forgot i was on a remote connection,
| and could not figure out why the thing quit responding when i
| typed eth0 down
| mananaysiempre wrote:
| The Debian package installer once asked me (a long long time
| ago) whether I want to restart sshd after a glibc update,
| saying existing sessions wouldn't be affected. That was a
| lie, apparently, because the SSH session I was updating the
| system died and the resulting SIGHUP killed the update
| process in a way that necessitated some recovery later.
|
| More seriously, Mikrotik routers have a nice feature where
| they will rollback your config change if the connection
| you're configuring one over stops responding to keepalives.
| Like a lot of Microtik features, it's probably copied from
| some Serious Business network OS, but I wouldn't know.
| Mr_Modulo wrote:
| Yes, the Safe Mode button. But you have to remember to
| press it before you start configuring the router and then
| exit Safe Mode when you're done.
| tremon wrote:
| _it's probably copied from some Serious Business network
| OS_
|
| I wouldn't know who came first, but it's a feature of JunOS
| (Juniper) as well: every config apply first applies the
| config, then waits for confirmation on the terminal where
| it was ran. If confirmation isn't given within X seconds,
| it reverts the config change.
| renewiltord wrote:
| Had a node that I was connected to over wireguard. Wanted to
| reset the wireguard conf. sudo wg-quick
| down wg0
|
| Nice one, mate. Had to drive back to log in and bring up that
| interface. I still do this, FWIW, but now I use `at` to
| schedule "up" 1 min in future haha. So far so good though
| it's not smart :)
| dylan604 wrote:
| Luckily for me, I just had to go down the hall to the data
| center, and then reset it with the local terminal. Compared
| to you, I learned the lesson on the cheap, but you got the
| bonus of a nice get out of jail free card. Neat CYA trick
| that I will keep in mind.
| huehehue wrote:
| or when I was futzing with display configs on a linux
| install, accidentally disabled my screen, and had to restore
| it blind
| kaba0 wrote:
| That's such an absolute hacker feeling, I was honestly
| surprised I got it to work, back then. Thanks for reminding
| me of that!
| m463 wrote:
| usually I do something like: # ifconfig
| eth0 down; ifconfig eth0 up
|
| that said, I have done this: # reboot
|
| ...on the wrong system
| dang wrote:
| All: if you want to argue about what "bricked" means, please do
| that at https://news.ycombinator.com/item?id=36946612, not
| here. But also consider: " _Please don 't pick the most
| provocative thing in an article or post to complain about in
| the thread. Find something interesting to respond to instead._"
| - https://news.ycombinator.com/newsguidelines.html
| swarnie wrote:
| Amazing that someone thought up a solution to a hypothetical
| problem 46 years ago, then fired it 30 billion km away
| bumby wrote:
| Aerospace has a very high quality standard compared to other
| industries.
|
| Lots of formal processes capture what would otherwise be
| informal design decisions elsewhere. In this case, they
| probably have reams of pages detailing a failure mode effects
| analysis (FMEA). One mode is "oops, we sent the wrong
| command" and the document would define the specific design
| mitigation(s) for that outcome until it reaches an accepted
| risk threshold.
| aetherspawn wrote:
| FMEDA probably. In recent times, fault tree analysis seems
| to be better for complex systems.
| behnamoh wrote:
| Sometimes we don't give enough credit to previous
| generations.
| detourdog wrote:
| I only give credit to previous generations. Firm believer
| that we only understand in retrospect.
| rcxdude wrote:
| It's not really hypothetical: losing communication with stuff
| in space is a very common failure mode and a huge amount of
| the system design is focused on making it as unlikely as
| possible (generally the radio system gets a huge priority in
| almost everything and there are a lot of failsafes built at
| every level to make it possible to reestablish communication
| if anything disrupts it).
| JdeBP wrote:
| Indeed. Voyager 2 has in fact been listening via its backup
| receiver since 1978.
| jjk166 wrote:
| It wasn't a solution for this specific problem. Spacecraft
| orientations are going to drift over time, periodically
| rehoming is the simplest way of dealing with it. That it
| doesn't care whether the orientation drift was natural or
| artificial is just a bonus.
| whartung wrote:
| The Voyager that's flying now is not necessarily the Voyager
| that was launched.
|
| The hardware is the same, but they've updated, patched, and
| rewritten the software that's running in it throughout the
| years.
|
| I'm not suggesting that the failsafe mode wasn't originally
| considered, and implemented, but simply that it doesn't have
| to be the case. They could have made changes to it over time.
| ck2 wrote:
| How the heck does it know where earth is?
|
| That's some impressive science there, not like there is a deep-
| space GPS.
|
| Does it look for the sun and figure out from there?
| detourdog wrote:
| it probably has both gyroscopes and star-charts for
| navigation.
| Dylan16807 wrote:
| So other people talked about how it does track, but there's
| another thing to note here.
|
| "The high-gain antenna has a beamwidth of 0.5deg for X-band,
| and 2.3deg for S-band."
|
| At 130-150 AU, the earth is always within about 0.4deg of the
| sun. Since commands are sent on S-band, pointing directly at
| the sun gets a pretty good signal.
| gregsadetsky wrote:
| I assume star tracking -- wikipedia seems to confirm
|
| "... and celestial referencing instruments (Sun
| sensor/Canopus Star Tracker) to maintain pointing of the
| high-gain antenna toward Earth"
|
| https://en.wikipedia.org/wiki/Voyager_2
| kyleyeats wrote:
| Dung beetles do this too.
| dylan604 wrote:
| As long as there's not too much light pollution.
| Fortunately for the dung beetles, their habitat isn't
| very urban. However, it's the little examples like this
| that make me a light pollution dork.
| gregsadetsky wrote:
| that's nuts!
|
| "- African dung beetles orient to the starry sky to move
| along straight paths
|
| - The beetles do not orientate to the individual stars,
| but to the Milky Way"
|
| https://www.cell.com/current-
| biology/fulltext/S0960-9822(12)...
|
| https://www.science.org/content/article/dung-beetles-
| navigat...
| gregsadetsky wrote:
| Sorry to self-reply, but this Q&A on "Space Overflow" about
| this specific star tracker is great:
|
| https://space.stackexchange.com/questions/43803/how-did-
| the-...
| rvnx wrote:
| Cool finding!
| vntok wrote:
| Basically the probe knows where it is because it knows where
| it isn't. By subtracting where it is from where it isn't, or
| where it isn't from where it is (whichever is greater), it
| obtains a difference, or deviation. The guidance subsystem
| uses deviations to generate corrective commands to drive the
| probe from a position where it is to a position where it
| isn't, and arriving at a position where it wasn't, it now is.
| Consequently, the position where it is, is now the position
| that it wasn't, and it follows that the position that it was,
| is now the position that it isn't.
| mcguire wrote:
| Ok, what is this quote from?
| wizofaus wrote:
| https://web.archive.org/web/20031218192524/http://w3.uwyo
| .ed...
| wholinator2 wrote:
| Wait, i don't understand. I was under the assumption that
| this text was a joke, but now I'm seeing it in reference
| to air force training materials? Is it a joke there as
| well or did someone actually write this text seriously,
| and plan for it's use as intelligible instruction?
| wizofaus wrote:
| There's oodles of references to this online but nothing
| really I've found so far explaining whether it was ever
| intended to be taken seriously in the first place. It's
| hard to imagine anyone doing so.
| KptMarchewa wrote:
| It's apparently from the 50s, as seen here:
| https://archive.org/details/sim_electronics-
| now_1959-03_30_3...
| [deleted]
| dang wrote:
| Stub for arguing about what "bricked" means. These comments were
| originally replies to
| https://news.ycombinator.com/item?id=36941191, but we moved them
| because the offtopic discussion was choking the thread.
|
| Normally I'd have marked the entire subthread offtopic, but
| hutzlibu's comment deserves to be at the top, even if it does use
| the word "bricked" wrong.
| glimshe wrote:
| A brick can't fix itself in case of problems. Just grab a
| brick, put it in a corner of the room and you'll see. It stays
| there doing nothing, it's kind of amazing how little it can do.
| deepspace wrote:
| There is also such a thing as subtlety and nuance. Words
| borrowed from physical objects do not need to have, and in
| general do not have exactly the same meaning when applied to
| software.
|
| I would love to see a picture of your computer pulling itself
| up by the straps on its physical boots the next time you
| press reset. Bleeding when a process is "killed".
|
| Even something as superficially similar to real-world
| behaviour a "queueing" is implmented in a very different way
| in software, for the most part.
| glimshe wrote:
| You can also see nuance in humor, in particular when
| recognizing a joke.
| burnte wrote:
| > In short, it was remote bricked, by giving it commands to
| rotate a bit. > But luckily it automatically readjust itself to
| earth automatically every half year exactly for these events.
|
| I remember when bricking something meant it was totally
| unrecoverable. Now it means "temporarily not working but will
| automatically heal".
| pohl wrote:
| My device is as worthless as a brick, but only for the 2 or 3
| seconds it takes for the tip of my finger to travel to this
| reset button over here... <Tongue in="cheek"/>
| x3n0ph3n3 wrote:
| Then it's not actually bricked.
| phaedrus wrote:
| Instead of saying "bricked" you could say Voyager 2 is "soft
| locked".
| hutzlibu wrote:
| A device that is acting as a brick cannot receive commands
| and is not useful at all. That is the current status of
| voyager 2.
|
| "Unbricking" will hopefully work automatically, because there
| is no other option. But that can also fail and there is no
| way to know, or influence it.
|
| I use bricking in the definition of mobile phone tinkerers ..
| there are many results for unbricking btw, but I just checked
| and with the first result it seems that Apple now uses
| unbricking for activating a new device. Because technically
| before, it is also just a brick - but here I would agree,
| that it is not a appropriate term, but rather should be for
| somehow broken devices.
| JdeBP wrote:
| What this is telling us is that attempting to condense to
| "it was bricked" has actually introduced ambiguity, and
| that "brick" doesn't really explain a technical situation.
|
| The JPL doco (https://news.ycombinator.com/item?id=36941433
| https://news.ycombinator.com/item?id=36942321) calls it
| "Command Loss".
| hutzlibu wrote:
| But you did understood my original comment? I described
| exactly in what way it "bricked". I used the term in the
| first place, because this was my first assoziation, when
| I learned about the situation. That "uppps" feeling when
| you did something wrong and there is no going back..
| (poor guy) "bricking" describes these vibes for me and
| "Command Loss" does not.
| [deleted]
| nomel wrote:
| It's not bricked, it's operating autonomously for some
| time. They're incredibly different modes of operation.
| lcnPylGDnU4H9OF wrote:
| I think it's reasonable to say that it is operating
| autonomously and is currently "bricked" as a
| colloquialism. There's a certain helplessness for NASA in
| this case, which is similar to bricking one's device.
| Instead of hoping that the repair shop can fix it, they
| have to hope that their engineering foresight was
| adequate.
| hutzlibu wrote:
| After trying to optimize my laptops energy settings under
| linux, I once also ended up with a device that was
| operating low level autonomously for some time. It just
| would not accept commands from me, nor the power button,
| nor anything else. The CPU also wasn't running, but
| something was.
|
| In other words it was effectivly a brick to me.
|
| But since it was not a surface pro (I considered buying
| instead of that one), I could open it and disconnect the
| battery.
|
| And in effect, unbricking it. Quite trivial fix sure, but
| nearly impossible with many modern devices, where the
| battery is glued in.
|
| My point is, not every mode of operation is desired,
| especially if you cannot change it. Then you might as
| well have a brick in terms of usefulness.
| nomel wrote:
| No. Your laptop was not operating autonomously, by
| definition.
|
| It was not making its own decisions, to achieve some
| goal.
| hutzlibu wrote:
| Parts of it were. To make some checks for some hardware
| (as part of an automatic comand line tool). They just got
| into an infinite loop. Down on the hardware level.
| kfrzcode wrote:
| That's not autonomous that's automatic
| rvz wrote:
| > I remember when bricking something meant it was totally
| unrecoverable.
|
| Precisely. 'Bricking' something means it is unrecoverable and
| is irreversible.
|
| No idea at what point in time the definition was changed to
| mean 'temporarily not working'.
| sangnoir wrote:
| Bricking oftentimes can be reversed using JTAG connectors.
| IMO - bricking describes thr state that a device is not
| operable, not irrecoverably so - just that its difficult to
| reverse.
|
| Also, it's not a technical term with a rigid definition,
| hence "soft-bricking"
| mindslight wrote:
| > _I remember when bricking something meant it was totally
| unrecoverable_
|
| It may have seemed that way to you, but actually no.
| "Bricked" has generally referred to devices that are likely
| straightforwardly recoverable, but for a lack of
| documentation from the manufacturer.
| burnte wrote:
| No, that's not true, and it's never been true. The
| definition was always "turned into a device which is
| electronically indistinguishable from a brick and
| unrecoverable." Maybe an expert could do some deep diving
| to bring it back, but if it's beyond recovery to most
| folks, then we'd call it a brick. If you have to desoldier
| a flash chip and sldier on a new one with a filesystem that
| isn't trashed or with corrected software, then we've
| debricked it, but that's really a deep level repair.
| mindslight wrote:
| Your division of "experts" vs "most folks" is doing a lot
| of work here, and speaks to my point.
|
| Most folks don't really know how to use say Android
| fastboot or recovery modes either, yet we wouldn't call a
| device with a wiped system partition "bricked".
|
| Most "bricks" are things like a bootloader getting
| erased. Reflashing that through the standard process of
| JTAG or another debug protocol is a straightforward
| action (after all, the manufacturer has to get the first
| bootloader on there to begin with). The port pinout and
| config info just hasn't been publicly documented by the
| manufacturer, which is what pushes it into the domain of
| "experts".
| burnte wrote:
| If doctors create the term "heart attack" and laypeople
| misuse it, that doesn't change the definition.
| mindslight wrote:
| I don't really know how to connect your analogy. As far
| as I'm aware, the term "bricked" arose out of
| software/firmware modding communities (eg Android) to
| describe devices that were beyond their general abilities
| to straightforwardly fix.
| burnte wrote:
| No, bricked was a word IT techs were using at LEAST as
| early as the early 90s as that's when I learned it. I
| learned it when someone bricked a network switch in 93.
| Originally in the Android world (and before android with
| Symbian and others) bricked meant you flashed firmware
| that really killed it, maybe you can bring it back with a
| JTAG connection or something more extreme. Then as
| modding became more popular, they started being able to
| more easily recover these and UNbricking became a thing.
| millerm wrote:
| I got into an argument with a fellow Tesla owner on a forum
| who was screaming their car was bricked after their 12V
| battery died. All they had to do was replace the battery. It
| wasn't bricked. I sure received a lot of vitriol for saying
| it wasn't bricked. If you can simply perform a maintenance
| task, it's not bricked.
| Ao7bei3s wrote:
| Nothing is ever truly unrecoverable. If a device was built,
| it can be built again.
|
| What is bricked vs recoverable has always greatly depended on
| time and effort, individual skill level, available
| hardware/software tools, documentation, crypto keys, physical
| access, willingness to replace individual parts etc.
|
| Sometimes, even within an org, some teams e-waste expensive
| devices that aren't bricked deeper than what other teams
| recover from as part of everyday workflow.
|
| Taking a typical network device as an example, where do you
| draw the line? Driving to a remote location to plug the cable
| into another port, pressing a reset button, booting from USB,
| flashing a new firmware with TFTP, plugging in an external or
| internal console cable, opening the case and soldering a
| header to get access to the console, doing the same with no
| documentation, or an unknown (but maybe Google-able or
| reverse engineerable) password, flashing firmware with JTAG,
| shipping the device back to the engineers (or shipping an
| engineer to the device)...? It's always been arbitrary.
| kfrzcode wrote:
| Hi, I have drilled my hard drives but need to recover them,
| can you help?
| Atheros wrote:
| If _you_ can 't fix it or find someone who can, it is
| bricked.
|
| If you are able to fix it then it is not bricked.
|
| One device may be bricked to one person but not to another.
| But that must still be the definition, right? Otherwise the
| word has no meaning.
| weinzierl wrote:
| I'd say "totally unrecoverable but physically intact". You
| wouldn't call a device bricked if it has the form of small
| pile of ashes.
|
| Then "totally unrecoverable" is rare and the term bricked has
| always been relative. Your bricked device may be as good as
| new to someone who has a JTAG adaper and knows how to use it.
| spullara wrote:
| Bricked things can't be unbricked (unless it wasn't actually
| bricked to begin with and was misdiagnosed). That is why it is
| called bricked.
| catiopatio wrote:
| Bricked things absolutely can be unbricked, e.g. by opening
| them up and reflashing a component, or otherwise engaging a
| special-case recovery path.
| wnoise wrote:
| True, but they don't recover themselves automatically.
| Atheros wrote:
| Bricked things can only be unbricked because the word has
| gradually lost most of its meaning. At this rate some day
| you're going to hear someone say they bricked their phone
| and mean that it ran out of battery and needs to be
| recharged.
| catiopatio wrote:
| No, this is what the word has always meant.
|
| An embedded device with a failed bootloader update is
| considered "bricked", even if you can open it up and
| reflash it with a valid bootloader.
|
| I don't know why folks are so insistent on gatekeeping
| the word, as if doing so demonstrates some superior
| personal knowledge.
| Atheros wrote:
| Some people don't just guard that word, they guard all
| words. We as a society even need to pass laws to protect
| the definition of words we use in commerce, like "ice
| cream" and "bread", otherwise people would abuse them to
| the point where they become meaningless.
| waihtis wrote:
| Would be very interested in any writeups on how NASA anticipates
| all the thousands of scenarios that can go wrong up-front and
| prepares for them. Sounds like there might be some useful
| thoughts there on how to write more resilient software
| Zealotux wrote:
| I thought just that about the JWST; I remember an interview
| with one of the lead engineers saying he wasn't stressed about
| the launch because he knew they had done everything possible to
| ensure success and everything was in fate's hands now.
|
| For Voyager 2, 45 years of uptime in the hazardous space
| environment, billions of miles away, is simply incredible.
| onetimeuse92304 wrote:
| I think it isn't about anticipating every possible scenario as
| much as designing a platform with enough redundancy and ability
| to measure, turn off/on, adjust, reprogram, etc. pretty much
| everything.
|
| Part of this is just necessary for ability to learn for future
| missions. If something fails in space, you want to be able to
| figure out what happened so that you don't make the same
| mistake the next time. And you don't have a chance to send a
| second mission just to "replicate" the problem.
|
| So you do things like build your test equipment into the probe
| so you can measure stuff while in operation. Or maybe make sure
| you have a switch for everything so that you can turn something
| on or off to see if the problem persists.
| alex_suzuki wrote:
| It's so inspiring when you see how these things are just built to
| last.
|
| quote: "In the past, engineers have compared keeping the probes
| operational to keeping an old car running. The tech is severely
| outdated, yet it keeps ticking over - a trend often seen in the
| spacecraft of past decades."
|
| At some point us humans will probably simply have forgotten how
| to maintain them.
| WWLink wrote:
| > At some point us humans will probably simply have forgotten
| how to maintain them.
|
| Nah, these systems are simple and incredibly well documented. A
| ton of people have operated them, too. They'll be fine.
|
| I'd expect something like that to happen to a university
| cubesat lol.
| op00to wrote:
| We can only hope that because they're so well documented, we
| can work around any "dead hardware" or "dead media" issue.
| Like, I hope the Voyager manual doesn't say "see disk 2 for
| firmware", and disk 2 has turned to dust 10 years ago.
| joshstrange wrote:
| The Foundation series covers this as well though I can't really
| recommend the book series. I tried a re-read when the TV show
| came out and felt pretty icky with how women were portrayed in
| the books. Also they aren't as good I remember. The TV
| completely diverges from the books but in a good way IMHO.
| Normally that bothers me a lot but after rereading the first
| book again I think I prefer the TV show.
| pstuart wrote:
| I loved the series as young teen but rereading the first book
| was a disappointment. I'll be checking out Foundation after I
| finish Silo.
| swozey wrote:
| Space opera is my favorite genre but I've failed to get
| through the Foundation series probably 20 times now so this
| may be terrible advice but it's recommended to not read
| them in publication order by Asimov himself.
|
| This has a good breakdown:
| https://www.reddit.com/r/Asimov/wiki/seriesguide/
|
| edit: Somehow I got Foundation mixed up with Banks' Culture
| series. I think I have gotten through most of Foundation if
| not all but I've had a hard time with the Culture series,
| there I usually start with Player of Games..
| joshstrange wrote:
| The Culture series is good but I've struggled with
| getting through it all as well. If you like space opera I
| can highly recommend the Honor Harrington series, the
| first book being On Basilisk Station [0]. This has held
| up for me for well over a decade and I've reread the
| entire series (~14 books IIRC) at least 4-5 times. I've
| heard it described as "Horatio Hornblower in space" but I
| never read that series so I can't speak to that.
|
| [0] https://www.goodreads.com/book/show/35921.On_Basilisk
| _Statio...
| a_e_k wrote:
| Incidentally, _On Basilisk Station_ is a free e-book at
| the publisher 's website [0]. They also have an online
| HTML version [1]. So you can try the first book in the
| series to see how you like it before purchasing any of
| the others.
|
| [0] https://www.baen.com/on-basilisk-station.html
|
| [1]
| https://www.baen.com/readonline/index/read/sku/0743435710
| bayindirh wrote:
| You should read "The Machine Stops" by E. M. Forster. Also,
| "Pump Six" from "Pump Six and Other Stories" will also do
| fantastic job of diving into this "forgetting how to maintain
| them" reality.
| freilanzer wrote:
| > "forgetting how to maintain them" reality
|
| I serve the Omnissiah.
| alex_suzuki wrote:
| Awesome, thank you! Just as I was again running out of things
| to read.
| the_af wrote:
| Pump Six really nails that feeling of "this thing we don't
| really understand keeps filling the log with warnings we
| don't know what to do about, let's ignore them and pray it
| just keeps working."
|
| Any similarities with the real world are surely coincidental.
| ilyt wrote:
| Many apps have warning/errors that are undecipherable from
| the very beginning, let alone 20 years later.
|
| Or only make sense when looking into source code that is
| long gone
| sand500 wrote:
| The worst is when the log line is constructed in a way
| that makes it really hard to find the source. Source code
| file name and line number is ideal but a tag like on
| Android auffices.
| eastbound wrote:
| And to say that people are paid to find traces of attacks
| in logs, while after 5 years, everyone ignores everything
| that's in the logs.
| [deleted]
| tleilaxu wrote:
| The most incredible thing about The Machine Stops by E. M.
| Forster is how casually prescient it is - first published in
| 1909!
|
| Instant messaging, video calls, the internet...
| tass wrote:
| Ringworld
| skywal_l wrote:
| Fire upon the deep, where space ships runs on a future
| version of unix and only one guy knows what the unix epoch
| means.
| larperdoodle wrote:
| I don't recall that in that book. Maybe you're thinking
| of A Deepness in the Sky? I haven't read that one yet.
| NikolaNovak wrote:
| I loved that aspect of it - it's becoming more and more
| true as we build more and more frameworks/abstractions.
| Once we got to Kubernetes and some of the modern web
| frameworks, the notion of "Programmer-at-Arms", the one-
| in-thousands master developer who'd actually dig into the
| depths of these abstractions, made perfect sense!
| marssaxman wrote:
| Yes, that bit is in "Deepness".
| twoodfin wrote:
| I think the reference is in _Fire_ : It's an offhand line
| about an ancient timekeeping system which the modern
| engineers mistakenly believe is calibrated to humanity's
| first steps onto another celestial body.
| r2_pilot wrote:
| As A Fire Upon the Deep is one of my favorite books (it's
| been a while since I've read it- my copy is currently on
| tour), I'd like to chime in and say I remember this
| reference, but I believe it's in A Deepness In the Sky,
| which goes more into Pham's backstory. It's definitely
| one of these two books though.
| Freaky wrote:
| > Take the Traders' method of timekeeping. The frame
| corrections were incredibly complex--and down at the very
| bottom of it was a little program that ran a counter.
| Second by second, the Qeng Ho counted from the instant
| that a human had first set foot on Old Earth's moon. But
| if you looked at it still more closely. . .the starting
| instant was actually some hundred million seconds later,
| the 0-second of one of Humankind's first computer
| operating systems.
|
| - Chapter 17, A Deepness in the Sky
| joshstrange wrote:
| I really love that series. It's been a little bit since I
| last re-read them but there are certain concepts/ideas in
| them that I still think of from time to time.
| joshstrange wrote:
| Loved this series when I first read it and it will always
| hold a special place in my heart but I did reread a few
| months ago and the way Teela Brown (and some other women)
| is talked about/to left me feeling very uneasy.
| winrid wrote:
| Keep in mind if you start the Ringworld series there's also
| a tie in series that starts 200 years before Ringworld
| (Fleet of Worlds) and both end with the same last book.
| Niven and M. Learner wrote so many books...
| Vecr wrote:
| I think the Man-Kzin Wars are also somehow related, but
| I'm not sure if it's technically in the same continuity
| or not.
| winrid wrote:
| Same universe, not sure if same characters. There are
| like 20 books, and I think some of them are community
| written.
| dcdc123 wrote:
| > which is currently almost 24 billion clicks away from Earth
|
| It makes no sense to use that term in this article not to mention
| it is usually spelled klick.
| travisgriggs wrote:
| "severs" huh. A bit clickbaity maybe? I think I'd gone with
|
| "OOPS, NASA gave V2 the wrong number to phone home. Engineers of
| old have last laugh and reassure 'it's OK, V2 will sort it out'"
| eimrine wrote:
| > The probe is currently around 32 billion kilometers from Earth,
| and gets 15km further away every second.
|
| I beg anybody to rephrase it understandingly with using some
| units similar to football fields. Is it possible to launch a
| little cheap rocket with a transmitter just to correct Voyager's
| position?
| gregshap wrote:
| Here's a 'wrong' but possibly helpful comparison, in the spirit
| of football fields:
|
| 32 billion kilometers is about 100 times the distance a
| satellite travels from earth to Mars. [1]
|
| That Earth-Mars trip is estimated in the same article to take 4
| months, so figure 400 months or 30+ years to shoot another
| satellite out to reach Voyager 2.
|
| This is ignoring planetary slingshot math, the extra speed to
| 'catch' voyager 2, and surely lots of other details. Personally
| I find years and "mars" to be more intuitive in this case than
| trillions of football fields.
|
| [1]https://mars.nasa.gov/mars2020/timeline/cruise/#:~:text=The%
| ....
| NoZebra120vClip wrote:
| Okay, if you tossed a football in 1977, and you tossed it
| really hard, like with the force of 5,000 Joe Namaths, then the
| football would have traversed 350 billion football fields
| (that's 44 stadiums per human on Earth) and the football would
| be speeding across 164 more fields per second; that's 7,380 in
| the time I took to post this comment.
|
| *Joe forces estimated
| ourmandave wrote:
| Once time travelers have conquered all the big challenges
| (i.e. kill Hitler, buy Apple in 1980, stop Skynet), they can
| go back and make sure Sir Isaac Namath discovers the law of
| gravity.
|
| It's the 24th century version of jacking with Wikipedia.
| whycome wrote:
| People keep going back to kill Hitler. But the resulting
| future is a butterfly effect nightmare result. So, people
| keep going back to save him. That's why he had so many
| close calls.
| kridsdale3 wrote:
| Wolfram Alpha just told me that it's 800,000 laps around
| Earth's equator away. You can probably compare that to a very
| long airplane ride (about a 45 hour flight) done nearly a
| million times.
|
| If that's not enough for human scale understanding, it's gone
| the same distance Earth goes in its orbit in 34 years.
| fodkodrasz wrote:
| > I beg anybody to rephrase it understandingly with using some
| units similar to football fields. Is it possible to launch a
| little cheap rocket with a transmitter just to correct
| Voyager's position?
|
| please tell me you are being sarcastic!
| i000 wrote:
| It is one trillion baker's dozens times the height of 1 fl oz
| of 200 proof ethanol in a quarter inch glass tube heated to
| 100F.
| castis wrote:
| > Is it possible.
|
| Using current technology we could probably make an object go
| faster than that so yes, it would be able to catch up.
|
| However, we'd probably just put better instruments on this new
| object and make that the priority.
| KineticLensman wrote:
| > Using current technology we could probably make an object
| go faster than that so yes, it would be able to catch up
|
| We could achieve slightly greater speed immediately after
| launch but we wouldn't be able to exploit the planetary
| gravity assists that accelerated the Voyager spacecraft.
| jl6 wrote:
| The antenna is pointing two degrees off course, so you wouldn't
| need to send a spacecraft all the way to catch up with Voyager
| 2 and fix it, you'd just need to launch a relay spacecraft to
| the nearest point that intersects the signal beam. If Voyager 2
| is about 32 billion km away, that point would be only about 1
| billion km away, assuming the signal is a straight line.
|
| "Only".
|
| It's probably not worth it.
| contravariant wrote:
| That sounds like too much, but turns out that 2 degrees is
| indeed about 1/30 radians.
| megous wrote:
| You mean sending this antenna to space?
|
| https://megous.com/dl/tmp/95ce96af5966be24.png
|
| :)
| 6510 wrote:
| It looks enough like an umbrella.
| emmjay_ wrote:
| > 32 billion kilometers > launch a little cheap rocket
|
| My sides.
| tgv wrote:
| Not only that, it also has to locate a pretty small object
| whose position is not well known, and course corrections, if
| they would help, from Earth take 18 hours (round trips 36).
| throwaway2990 wrote:
| About 30,000 AR15 lengths per second.
| __alexs wrote:
| Since the muzzle velocity (1km/s) of an AR15 is about 1/15th
| the speed of Voyager (15km/s), if you had a matryoshka doll
| of AR15s that could fire other AR15s you would only need 15
| nested AR15s to shoot a bullet as fast Voyager is travelling.
| jjk166 wrote:
| Note that this is actually how multi-stage rockets work.
| __alexs wrote:
| Are multi stage bullets a thing?
| Rebelgecko wrote:
| In Russian, Konstantin Tsiolkovsky famously described the
| "tyranny of the Kalashnikov equation"
| desmond373 wrote:
| Its 3250000 australias away and gets 1 more australia away
| every 10 days.
|
| Im not sure if thats what you wanted but australias per day is
| my new favourite unit.
| selimthegrim wrote:
| Australia is wider than the moon so not a terrible unit
| chrismorgan wrote:
| Hmm... moon circumference is 10Mm, Australia width is 4Mm,
| so you can lay 21/2 Australias end-to-end when wrapping
| them around. Figuring out any 2D tessellation is left as an
| exercise for the reader. But the process of wrapping
| them... well, the biggest earthquakes on record only
| damaged half a dozen buildings and structures, to a few
| million dollars' damage; this process might just cause
| rather a lot more. Like a zillion Australias divided by a
| Tahiti or so, that many times as much. Yeah. It'll surely
| also depend on what depth you peel the Australias at.
| amenhotep wrote:
| 15 km further away every second and 1 Australia every 10 days
| implies that it would take 10 days to cross Australia if you
| were going at 15 km per second, which from my understanding
| of travel options there means either planes and trains are a
| lot faster than I was aware or something's got mixed up
| somewhere with these numbers!
| onetimeuse92304 wrote:
| > 15 km further away every second
|
| Nope, not true. Not every second. Depends on the time of
| year. For a few months, each year, Voyagers actually get
| closer to Earth.
| ummonk wrote:
| Check your math. It gets ~65 australias away each day.
| igleria wrote:
| constant 15 km/s and 32 billion km gives something like 67
| years. IF a 120 yard football field was equivalent to this
| distance and a very slow fly is moving through it, it means
| it's advancing 1.8 yards per year.
|
| or something, dunno.
| hans_castorp wrote:
| I gets 2 poronkusema further away every second
| gerdesj wrote:
| 0.5003% of the maximum velocity of a sheep in a vacuum (1)
|
| (1) https://www.theregister.com/Design/page/reg-standards-
| conver...
| eddieroger wrote:
| Kind of tangential, but I've been watching a lot of original
| Star Trek recently, so I was curious about how far this was in
| lightyears, probably because of the Enterprise's proclivity to
| run in to Voyager.
|
| If it's 15 billion miles away (sorry for my Freedom Units), it
| is 22 light-hours away, or 0.0026 light years away (unless my
| Google-fu is way off). If we could move at the speed of light,
| which we can't, it would still take nearly a day to get there.
| So if we were on the Enterprise moving at Warp 1, it would take
| a day to get there and reorient it back towards Earth. If we
| could move at Warp 10, we'd have already been there and fixed
| it.
| kridsdale3 wrote:
| 22 hours is assuming you only wanted to reach that location
| (and not stop to visit the craft) and you had instant
| acceleration up to c for your velocity, which would be
| infinite G forces and turn your cells in to quantum foam.
|
| More realistically, even if say we did have a light speed
| capable craft, we'd be limited by the forces for accel and
| decel to have a starting speed of 0 relative to Earth, and
| ending speed of 0 relative to Voyager. The limits would be
| determined by the withstanding capability of the bodies of
| the pilots, or the mechanical strength if it were another
| drone.
|
| I don't feel like doing the math properly, so I asked GPT4
| this question:
|
| > let's say we wanted to move a human astronought in a
| spacecraft to the current position of Voyager 2 which is 22
| light-hours away. We want to get there as fast as possible,
| and arrive at a co-moving frame with Voyager, which has a
| relative velocity of 32000 miles per hour moving away from
| the Earth. Assuming the astronaut can withstand a g-force
| maximum on their body of 6G, and using that to inform the
| maximum accelleration and deceleration for the voyage, how
| long does it take to reach the Voyager 2 co-moving frame?
|
| Response:
|
| Firstly, let's convert everything to consistent units. Here
| we'll use hours for time, miles for distance, and miles per
| hour^2 for acceleration.
|
| 1 G is approximately equal to 22 miles/hour^2. Therefore, 6G
| is approximately 132 miles/hour^2. The distance to Voyager 2
| in miles is 22 light-hours * 670616629 miles/light-hour =
| approximately 14753561838 miles.
|
| Assuming we accelerate at 6G until halfway, then decelerate
| at 6G for the second half, we can use the kinematic equation:
|
| d = 0.5 * a * t^2
|
| Solving for t when d equals half the total distance gives:
|
| t = sqrt((2 * d) / a)
|
| Substituting in the values:
|
| t = sqrt((2 * (14753561838 miles / 2)) / 132 miles/hour^2) =
| 84331.5 hours
|
| So, the total time to reach Voyager 2 while maintaining a
| maximum acceleration/deceleration of 6G is approximately
| 84331.5 hours * 2 = 168663 hours, or about 19.25 years.
|
| This is a rough estimation and doesn't take into account the
| relative velocity of Voyager 2 or relativistic effects at
| high speeds.
|
| It also assumes constant acceleration and deceleration, which
| wouldn't be feasible with today's technology due to fuel
| constraints.
|
| -------------
|
| So our 22 hour lightspeed trip would still take 19 years if
| it had a human onboard.
|
| The biggest limitation with sci-fi travel isn't breaking
| relativity, it's finding a way to accelerate squishy meat-
| bags. This person will be living at an effective weight of
| nearly 1000lbs for 20 years, which will really mess them up.
|
| For the sake of the longevity of our pilot, I asked to re-run
| the calculation limiting the on-board gravity to 1G. It now
| takes 114 years to reach Voyager's current position, which by
| then will be much farther. It turns out we will never catch
| up, and reaching it is impossible if we limit our craft to
| earth like conditions necessary for human health.
| Dylan16807 wrote:
| _Stop making the chatbot do math._
|
| And come on, you can sanity check those numbers.
|
| "1 G is approximately equal to 22 miles/hour^2."
|
| Think about this. That means it would take you an _hour_ to
| reach _22mph_.
|
| The real speed you'll be going is 22 miles per _second_.
|
| And sqrt(14753561838 / 132) is 10572, not 84331. That's not
| even close.
|
| Also it used the Voyager 1 distance which is significantly
| different.
|
| Once we fix all the numbers, each half of the trip is
| sqrt(20 billion km / 60m/s^2) which is a week. So two weeks
| total.
|
| At 1G, each half is 16.4 days, so it takes a month total.
| ohthehugemanate wrote:
| It's about 3.5 trillion NFL football fields away. 15km/s is
| about 33,000 mph - more than 10x the speed of sound, and faster
| than a bullet. Does that help?
|
| We are talking about distances that are so big, there is no
| comparison that makes sense. Nothing else IS that big. The
| numbers are literally "astronomical". If you're struggling to
| wrap your head around it, you're doing it right.
|
| "Space is big. You just won't believe how vastly, hugely, mind-
| bogglingly big it is. I mean, you may think it's a long way
| down the road to the chemist's, but that's just peanuts to
| space." -- Douglas Adams
| cheschire wrote:
| When you start getting beyond the "thousands of football
| fields" it starts becoming difficult to conceptualize. In
| this case, even though GP was asking for football fields, it
| may be easier to visualize it as flying nearly 800 thousand
| times around the entire equator of earth. And voyager is
| going around the equator roughly once every 45 minutes or so.
|
| So to catch up, you would have to be faster. Let's say you
| were able to travel around the equator in 15 minutes, so
| you're gaining 30 minutes per equator. If my napkin math is
| right, it would take you roughly 45 years to catch up to
| voyager.
| messe wrote:
| > 800 thousand times around the entire equator of earth
|
| This probably wasn't your intention, but putting it in
| terms like this, for me anyway, actually drives home just
| how _short_ a distance the Voyager probes have travelled.
| cheschire wrote:
| I just wanted to make the distance something that could
| be understood and processed. Sounds like it worked!
| messe wrote:
| You definitely did a good job. I'm an avid sci-fi reader,
| write it as a hobby, spend a not-insignificant amount of
| my free time reading up on space news, and even have a
| degree in mathematical physics; this is the first time in
| a long time that an analogical choice of units has had an
| impact on my perception like that. Well done!
| ilyt wrote:
| > When you start getting beyond the "thousands of football
| fields" i
|
| I feel like that line is somewhere between 5 and 15 for
| americans, and not "thousands". And probably at around "oh
| the handegg one, no, I have no idea how big one is in the
| first place" for rest of the world
| conductr wrote:
| As an American, I've never seen more than maybe 2-3
| football fields next to each other. They're usually stand
| alone items so that is even rare. Imagining them in
| plural at all is something people likely do with a large
| degree of error is my guess, even for us American's that
| are familiar with the size of a single field. It's a
| awfully small unit for anything related to space. Even a
| kilometer which is ~11x as long as an American football
| field is a small unit for space.
| dragonwriter wrote:
| For order of magnitude descriptions, American and
| Association Football fields can be treated as
| approximately equivalent lengths. (The former is slightly
| larger counting the endzones as part of the size,
| slightly smaller if not counting them.)
| ip26 wrote:
| Your parent was not suggesting to catch it, but rather to
| launch a transmitter to intercept Voyager's radio beam as a
| relay. Unnecessary, but creative.
| cheschire wrote:
| My math also didn't account for the fact that voyager
| would continue traveling in those 45 years you'd be
| trying to catch up, so it would actually take longer to
| catch up to it anyways.
| withinboredom wrote:
| It's crazy when you consider that the sun is 8 LIGHT MINUTES
| away from earth. Light can go around the entire planet
| hundreds, no, thousands of times in that same period. Space
| is huge. Incredibly huge.
| onetimeuse92304 wrote:
| > 15km/s is about 33,000 mph - more than 10x the speed of
| sound
|
| Well, technically, 15km/s IS "more than 10x the speed of
| sound". An average car, is, TECHNICALLY, more than twice the
| size of a bicycle.
| ohthehugemanate wrote:
| honestly I was just shooting for easy round numbers. "More
| than 43x the speed of sound" doesn't have the same ring to
| it. And besides, as we all know "technically correct is the
| best kind of correct!" :)
| onetimeuse92304 wrote:
| So what was wrong about "40 times the speed of sound"?
|
| Also, I don't particularly like the speed of sound for
| this comparison. Most people think of speed of sound as
| speed of sound at about sea level pressure, in gas
| composed of around 78% nitrogen and 21% oxygen and at
| roughly 25C temperatures. But the speed of sound is
| highly dependant on the medium and its temperature and
| pressure. There actually can be sound waves in space
| (pressure waves in interstellar gas resulting from
| various astronomic phenomena) and they propagate at very
| wide range of speeds, typically somewhere between 10 and
| 100km/s.
|
| The main reason to use "speed of sound" is because
| important things change when objects travel at little
| below or above speed of sound in the medium they are in.
| But this is only useful in relation to the actual medium
| the object travels through.
|
| One place where it trips people up is when they are
| talking high altitude airplanes or rocketry. They are
| talking about something traveling at "X Mach", or "X
| times the speed of sound" and then I try to figure out if
| they mean X in relation to the speed of sound up there or
| the speed of sound at sea level. Just a nightmare trying
| to use it to convey speeds even within confines of our
| atmosphere.
| bluejekyll wrote:
| A nice feature of using the speed-of-sound as a
| measurement unit is that people know how difficult it is
| for aircraft to achieve it. So it makes it clear how much
| faster these things are going. We don't have anything
| comparable between the speed-of-sound and the speed-of-
| light, do we? I suppose you could use escape-velocity,
| that isn't something as many people know, but does I
| guess get you closer to the speeds in question.
| ilyt wrote:
| > A nice feature of using the speed-of-sound as a
| measurement unit is that people know how difficult it is
| for aircraft to achieve it.
|
| But it's not aircraft ? It's trivial for spacecraft to
| achieve it
| onetimeuse92304 wrote:
| There is nothing trivial about it. The only reason
| Voyagers are traveling so fast is we were very lucky at
| the time and got gravity boost from pretty much
| everything we could get gravity boost from.
|
| But yeah, it is not comparable as the challenges for
| spacecraft and planes are completely different.
| dragonwriter wrote:
| > The only reason Voyagers are traveling so fast is we
| were very lucky at the time
|
| "Lucky", only in the sense that (1) completing a large
| government project on time, and (2) not having some kind
| of disaster (particularly, at launch) screw up the
| mission require a certain degree of luck of luck on top
| of planning and execution (though, not relying completely
| on that luck is also why there were two Voyagers): we got
| all the gravity boosts because the mission was planned
| around an alignment that enabled it to do that and
| visiting each of the outer planets (which was really the
| main goal; the beyond the solar system part was gravy.)
| burnished wrote:
| Trivial seems the wrong word here. Picking your nose is
| trivial. Space travel is exceptional.
| FredPret wrote:
| I think Mach numbers are always given for the situation
| the aircraft is in at the time
| onetimeuse92304 wrote:
| That's the idea. But quick survey of people in my
| vicinity confirmed most people think about Mach numbers
| as just another unit for speed of sound.
| dragonwriter wrote:
| > Well, technically, 15km/s IS "more than 10x the speed of
| sound".
|
| Technically, the speed of sound depends on the medium, and
| 15km/s is _much slower_ than the speed of sound in
| interstellar space. (Which the sources I can find give at
| ~100km /s.)
| roody15 wrote:
| Good description.. reminds me of Vernor Vince's description
| in his novels.
|
| We are truly lost in a "The Deep" ... as in absolute
| nothingness
| danbruc wrote:
| The number is wrong to begin with, Voyager 2 is about 20
| billion kilometers from Earth [1] if I did not do the
| conversion incorrectly as NASA shows it in miles only.
|
| [1] https://voyager.jpl.nasa.gov/mission/status/
| louthy wrote:
| It's 128,000,000,000,000 bald eagles
| Merad wrote:
| > Is it possible to launch a little cheap rocket with a
| transmitter just to correct Voyager's position?
|
| Possible, maybe. Little or cheap, definitely not. Both Voyager
| probes relied on a unique alignment of the planets in the outer
| solar system that allowed them to get a series of speed boosts
| using gravity assists from the gas giants. If we wanted to
| launch a rocket anytime in the near future that would be able
| to catch up with Voyager 2 we'd probably have to rely on good
| old fashioned brute force (rocket power). But then if you want
| the rocket to catch up in the next thousand years it's going to
| need REALLY big ass rockets to catch up with Voyager... and if
| you want it to rendezvous with Voyager instead of just zipping
| past, it will need to haul more rockets all the way out to
| Voyager so it can slow down and match speeds (which means even
| bigger rockets to launch from earth, etc.).
|
| tl;dr - space is big and the rocket equation is brutal.
| kamaal wrote:
| >>and gets 15km further away every second
|
| >>I beg anybody to rephrase it understandingly with using some
| units similar to football fields.
|
| More like it can go from Earth to Moon in like 8 hours(or so).
| fennecfoxy wrote:
| Apparently 32 billion km is about 29.65 light hours, so to
| catch up we'd need a magical massless spacecraft to travel at
| the speed of light for a bit over a day to reach it. Hopefully
| that demonstrates how utterly infeasible it would be to reach
| it.
|
| It's also near the end of its usable life so it wouldn't be
| worth it anyway.
|
| And actually, according to
| https://voyager.jpl.nasa.gov/mission/status/ it's actually
| 19,936,472,690 km from Earth so I think like 20ish light hours
| or so.
| zichy wrote:
| Not sure if you are trolling.
| qingcharles wrote:
| I'm think GP means we could launch a rocket to the place
| where Voyager thinks Earth is supposed to be (where its
| antenna is pointing towards) and fire off a signal to tell it
| to move.
| elif wrote:
| It's been travelling the width of the earth every 14 minutes
| for the last 47 years.
|
| To reach the point 2 degrees from earth would take 1.64 years
| at that speed.
|
| To reach that point before October 15th it would need to travel
| about 9x faster than falcon 9 second stage or almost twice as
| fast as the fastest spacecraft in history.
|
| But it would need significant additional time and fuel to slow
| down such that it didn't immediately blow past that point and
| become useless, so it would need an even higher speed.
| awestroke wrote:
| How to tell if somebody is an American
| chank wrote:
| -
| rob74 wrote:
| Then they would also use football fields (but think of
| soccer fields).
| louthy wrote:
| Only Americans call football 'soccer'
| skissane wrote:
| > Only Americans call football 'soccer'
|
| Australians call it "soccer" too. Disambiguates it from
| Australian Rules, Rugby League and Rugby Union
| iainmerrick wrote:
| The word "soccer" actually comes from England! From
| Wikipedia:
|
| _The term soccer comes from Oxford "-er" slang, which
| was prevalent at the University of Oxford in England from
| about 1875, and is thought to have been borrowed from the
| slang of Rugby School. Initially spelled assoccer, it was
| later reduced to the modern spelling._
|
| "Football" almost always means soccer (association
| football) in the UK, but there are also things like rugby
| football and Gaelic football.
|
| _Edit to add:_ you need to disambiguate when other forms
| of football are popular (eg at Oxford university) but
| these days soccer is the most popular sport by a huge
| margin.
| vinay427 wrote:
| If you ignore much of the majority English-speaking
| world, then yes, that would be accurate.
|
| https://brilliantmaps.com/football-vs-soccer/
| sho_hn wrote:
| Dave from EEVBlog just visited a facility communicating with
| Voyager 2:
|
| https://www.youtube.com/watch?v=586Zn1ct-QA
|
| https://www.youtube.com/watch?v=vUvzgZt1Vug
|
| There's a part 3 with a tour of the complex.
| whartung wrote:
| I was fortunate to have the opportunity to visit Goldstone, up
| in the California desert on Fort Irwin. It's not open to the
| public very often.
|
| I got to visit most everything there, including the 70m
| telescope. It was just a cool space tech nerd day of tours,
| presentations, and sunshine.
|
| The dichotomy of the 70m antenna is interesting is that it
| broadcasts 450 kilowatts of power out into space, but has to
| receive and decode, "as small as 1 billionth of 1 billionth of
| 1 watt" signals from the space craft.
|
| One of the reasons its on a military base is to restrict the
| airspace above it so that they don't accidentally cook some
| aircraft that happens to overfly the antenna when it's
| transmitting.
|
| It's truly astonishing they're able to pull that off, frankly.
| kylehotchkiss wrote:
| 450 kilowatts? Is this the most powerful transmitter on
| earth? Where does it source the electricity for this?
| silverscania2 wrote:
| It's a re-upload from 2017, just in case anyone else thinks
| they are going crazy like me.
| mlindner wrote:
| Why would someone reupload their own old videos?
| sho_hn wrote:
| "NOTE: This video is a re-release from the EEVblog Discover
| channel from 2017, to hopefully find a new audience."
|
| Worked on me, I guess :-)
| Nifty3929 wrote:
| I used to do remote work in firewalls quite often, and after
| locking myself out once or twice, I came up with a new habit:
| before making any changes I would schedule a reboot for 5min out
| which would revert any changes. That way if I locked myself out I
| could just wait for the reboot and get back in.
| networkchad wrote:
| [dead]
| stouset wrote:
| I did a similar thing in the early days of my career, but I
| actually _caused_ an outage as a result.
|
| In this instance, I was adding itables rules to a host. I wrote
| a script that add all the rules to enable expected network
| traffic, then set the default policy to DROP. Before running
| this script, I scheduled another script to be run which would
| delete all the rules I'd added. I did _not_ remember to set the
| default policy to ALLOW.
|
| The script runs, everything looks good. Five minutes later,
| pagers start going off.
|
| Thankfully we were able to remotely power-cycle the host and
| didn't have to drive down to the datacenter in order to fix the
| issue.
| knorker wrote:
| Standard practice on Cisco routers, where I've worked, is to do
| "reload 5" before doing dangerous things.
|
| On juniper, it's "commit confirmed".
| comboy wrote:
| or safe mode on mikrotik
| dang wrote:
| And then if it worked for those 5 min before the reboot, you'd
| redeploy the change 'for real', without a reboot?
| 2snakes wrote:
| Yeah, there are different kinds of memory in firewalls. Like
| a running-config and a startup-config. If you just change the
| running-config and don't commit to the startup-config, when
| the reboot takes place it'll pull the config from the (non-
| modified) startup-config instead, reverting changes.
| Nifty3929 wrote:
| copy run start!
| Nifty3929 wrote:
| My typical workflow was:
|
| - Schedule the reboot
|
| - do my changes
|
| - Make sure everything was working properly
|
| - Go get lunch
|
| - Notice a bunch of pages and alarms about a firewall going
| offline
|
| - Rush back to my office
|
| - Login to the firewall
|
| - Schedule the reboot
|
| - Re apply the changes
|
| - Test it again
|
| - CANCEL THE FING REBOOT THIS TIME
|
| - Eat my now cold lunch
| hsbauauvhabzb wrote:
| 'sleep 300 && init 6' was my go-to, but since then systemd has
| made firing init 6 unreliable (it won't trigger a reboot
| locally if root has an open ssh session, at least on Ubuntu).
| prox wrote:
| This is clever, I like it.
| knorker wrote:
| "commit confirmed" from Juniper routers is much better
| snuxoll wrote:
| Mikrotik safe mode gets a 3/5 in comparison - it reverts
| changes you made if you lose connection to the router, so
| it does it's job as an anti-lockout mechanism; but I much
| prefer the atomic nature of a confit commit on junos still.
| elif wrote:
| I can't believe it doesn't attempt to auto-calibrate after x days
| of no signal in some kind of exponential ramp up
| Aardwolf wrote:
| Why aren't there more space ships like voyager 2, going outside
| the solar system but still providing some signal?
|
| It's got to be possible to launch some in space now and have them
| go faster than voyager 2, so that the outside can be explored
| faster?
| dragonwriter wrote:
| > Why aren't there more space ships like voyager 2, going
| outside the solar system but still providing some signal?
|
| Because that part is a side benefit not worth launching for,
| and the main motivation (grand tour of the outer planets) for
| the Voyagers relied on a once-in-175-years alignment of the
| planets.
|
| But maybe we'll have nice probes ready to launch in the 2150s
| next time the alignment happens.
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