[HN Gopher] Voyager 1 Breaks Its Silence with NASA via Radio Tra...
___________________________________________________________________
Voyager 1 Breaks Its Silence with NASA via Radio Transmitter Not
Used Since 1981
Author : elsewhen
Score : 166 points
Date : 2024-11-11 13:48 UTC (6 days ago)
(HTM) web link (www.smithsonianmag.com)
(TXT) w3m dump (www.smithsonianmag.com)
| 31337Logic wrote:
| Truly amazing!!
| iamgopal wrote:
| Can we send a voyager 3 with much advance battery and sensor, and
| at much faster speed so that it may reach farther than voyager 1
| and 2, in let's say just couple of years ?
| HWR_14 wrote:
| No, we cannot.
|
| We could make a Voyager 3, but I don't think there is any way
| to expect it to catch up with currently feasible technology.
| And it could only be launched at specific times.
|
| It certainly could have more advanced sensors and batteries. I
| don't know if the battery improvement would really matter on a
| decades long mission.
| rlpb wrote:
| As far as I understand their speed mostly comes from gravity
| assists from Jupiter, so you'd have to wait for suitable
| orbital alignments and the basic technology for "much faster
| speed" doesn't exist.
| dnh44 wrote:
| I never actually knew that. My mental model for how this
| works was way off; I'll have to read more.
| baq wrote:
| Play Kerbal Space Program (the original, not the sequel).
| You'll become an orbital mechanics pro in a couple days.
| skissane wrote:
| > and the basic technology for "much faster speed" doesn't
| exist.
|
| Various forms of nuclear propulsion have been investigated.
| None of them are anywhere near ready for missions, but that
| seems to be more due to lack of investment in their
| development (and
| environmental/legal/regulatory/geopolitical/etc concerns)
| than any scientific obstacle. If NASA/etc were really serious
| about it (as in willing to spend multiple billions a year on
| it), it could probably be made to work in only a few years.
| ivan_gammel wrote:
| This probably can happen as soon as there's some
| manufacturing and mining capacity beyond LEA, so that it's
| safe to use nuclear technology without any environmental
| impact. Moon is an option here, so likely it's 5-15 years
| after first Moon base is established (I'd expect
| exponential growth of it).
| skissane wrote:
| > This probably can happen as soon as there's some
| manufacturing and mining capacity beyond LEA, so that
| it's safe to use nuclear technology without any
| environmental impact
|
| The idea pursued nowadays is you launch using chemical
| propulsion and then only turn on the nuclear propulsion
| once you reach a safe distance from Earth. This is
| different from the original 1950s Project Orion which
| proposed to use nuclear pulse propulsion (i.e.
| repurposing nuclear weapons for propulsion) from the
| surface to orbit, which would have produced enough
| fallout to likely kill a handful of people per launch (in
| the long-run through higher cancer rates). The question
| then is - is it safe to launch nuclear material to orbit
| using chemical propulsion? Yes, we can secure it in
| containers designed to survive catastrophic loss of the
| launch vehicle. But, will the general public believe it
| is safe, even if it actually is? Possibly not-which is a
| political obstacle rather than a technical one.
|
| The other issue is that nuclear propulsion systems can be
| too large/heavy to launch on a single chemical rocket,
| but you could launch them as multiple modules assembled
| together in orbit.
|
| I don't think this need or should depend on off-Earth
| manufacturing or mining capacity. I think it is going to
| be a long time before the highly complex manufacturing
| supply chains needed to turn raw materials into cutting
| edge technology like nuclear space propulsion systems
| exists off Earth. But we should be able to manufacture
| them modularly on Earth, such that in space we'd be doing
| module assembly rather than manufacturing.
| FriedPickles wrote:
| > the basic technology for "much faster speed" doesn't exist.
|
| ...but we're very close. The next technique will be flying
| near the sun then deploying a solar sail for a huge speed
| boost. Voyager goes 3 AU/yr, solar sail boost with todays
| technology will enable 7-9 AU/yr.
|
| Highly recommend watching Slava Turyshev discuss his work on
| an SGL telescope, which employs this technique.
|
| https://www.youtube.com/live/lqzJewjZUkk?si=57VS4oqbaKEXmyOR
| gruturo wrote:
| Yes, but mostly no, also no, and, frankly, why would we.
|
| Yes: we could lift off a much heavier spacecraft, give it
| plenty of fuel, and many of its parts would be lighter than
| their 1970s equivalent, giving us lots of room for modern
| sensors
|
| No: the "battery" in the old ones is nuclear and it's going to
| be difficult to beat that (but not impossible: a nuclear
| stirling engine, either powered by fission or by decay, e.g.
| https://www.nasa.gov/technology/rps/stirling-convertor-
| sets-...)
|
| Also no: the old Voyagers benefited from a lot of gravity
| assists from half the solar system, thanks to an alignment
| which won't happen again until 2151
| (https://space.stackexchange.com/questions/5075/when-is-
| the-n...), so unless you're not in a hurry, we won't have that.
|
| Why would we: the _point_ of the Voyager crafts was to do close
| flybys and collect plenty of data from the outer planets, not
| to go as far away and as fast as possible. You want to be as
| slow as possible near them, so you have science time. You're
| rushing this part in order to get right away to the centuries
| of nothing which follow?
| voytec wrote:
| > the "battery" in the old ones is nuclear and it's going to
| be difficult to beat that
|
| Newer atomic batteries can theoretically last centuries
| instead of decades.
|
| V'ger 1 atomic battery is based on Plutonium-238 which has a
| halflife of ~88 years. It's down to ~210W output from initial
| 470W at launch time.
|
| Americium-241 has a half-life of over 400 years.
| gruturo wrote:
| The longer the half life, the lower the power output, no
| free lunches. But by putting the same suitable radioactive
| lump in a stirling engine you can extract 4 times as much
| electricity: https://en.wikipedia.org/wiki/Stirling_radiois
| otope_generato...
|
| So yes maybe with Americium-241 we could have something
| which lasts 4 times a much _and_ gives us the same amount
| of power thanks to a SRG.
| gray_-_wolf wrote:
| But it seems to involve moving parts, so I am not sure
| the reliability trade-off is worth it for
| decades/centuries long missions.
| rightbyte wrote:
| Using a sterling motor would give you mechanical wear.
| moomin wrote:
| Finding "V'ger" hilarious.
| Self-Perfection wrote:
| We probably do not need to wait for ideal planets position to
| outrun Voyagers. We have ion thruster now with much higher
| specific impulse!
|
| Voyager-2 gained about 10 km/s at Jupiter, about 5 km/s at
| Saturn, about 2 km/s at Uranus, and lost about 2 km/s at
| Neptune. [1]
|
| Dawn spacecraft gained 11.5 km/s from ion thrusters.
|
| So just gravity assist maneuver just around Jupiter alone +
| massive tank for ion thrusters gas might give 20+ km/s
|
| Though I agree that value of such a mission would be low.
|
| [1] https://www.planetary.org/articles/20130926-gravity-
| assist
| gruturo wrote:
| Unfortunately a gravity assist maneuver is almost
| "incompatible" with an ion thruster.
|
| If you approach e.g. Jupiter you gain speed (it's pulling
| you in), which you then lose as you get away from it (as
| it's still pulling you in, meh). Gravity assists work
| because you use your chemical rocket right when you are
| closest and speed away, "robbing" Jupiter of the chance to
| claim the energy it lent you on approach.
|
| Ion thrusters have very low thrust, so you would accelerate
| veeeeery slowly away from Jupiter's gravity well - and in
| this time it will keep affecting you and slowing you down,
| and the whole thing would be barely worth doing.
|
| You could bolt on a very simple solid rocket booster just
| for the gravity assist, of course, but its ISP will be
| lower and you'll have to carry its mass until you can
| expend it.
| m4rtink wrote:
| I think you are mixing up gravity assist with the oberth
| effect. I'm pretty sure Voyagers did no massive burns
| close to the giant planets for example. A (so far
| theoretical) Solar Oberth maneuver on the other hand...
| plorg wrote:
| Just a small aside, are Stirling engines used on other
| spacecraft? The Wikipedia article suggests development was
| largely abandoned a decade ago. My first glance concern would
| be that because it's reliant on moving parts it is liable to
| fail sooner than a purely thermoelectric RTG (due to part
| wear, lubricant leaks, fatigue, etc). This would seem to be
| quite important on the timeline of a probe that is going to
| take a long time to reach the subject of its investigation.
|
| Which, to your point, only works against the idea of
| hypothetical Voyager 3.
| hinkley wrote:
| Strictly speaking, the voyager missions already are the faster
| space craft that caught up with another spacecraft - Pioneer 10
| and 11.
|
| Looks like we lost contact with 10 and 11 in 1995 and 2006
| respectively. They both ran out of power and shut down.
|
| The voyager missions used a rare planetary alignment to get
| boosts. And a radioisotope thermal engine that has gotten
| pushback in later spacecraft designs, although they have
| ceramic versions now meant to address most of the issues.
|
| That said, New Horizons, which gave us those lovely shots of
| Pluto, was launched in 2006. But it is traveling faster than
| the Pioneers but slower than Voyagers, so it'll be the third
| farthest away at some point.
| NikolaNovak wrote:
| My understanding is that
|
| 1. Our rocket / propulsion technology today may be cheaper (thx
| largely to SpaceX), but it doesn't really necessarily provide
| MUCH more delta V. Meanwhile
|
| 2. Voyager launches relied on a once-in-a-blue-moon (not quite
| once in two centuries) alignment of various planetary bodies to
| give a spectacular orbital slingshot boosts.
|
| So my limited understanding is that we can't really overtake
| voyagers very easily. Whether our current technology coild be
| made more reliable in the long term is another good point of
| discussion :-)
| vikingerik wrote:
| The alignment isn't what matters for overtaking Voyager.
| Jupiter alone is enough, and New Horizons nearly did. Jupiter
| accounts for the vast majority of any gravity-assist plan.
| Saturn has 30% the mass and 2/3 of the orbital velocity, so
| it could only add 20% more over what you get from Jupiter
| alone, and the ice giants are smaller and slower yet.
| Denvercoder9 wrote:
| > New Horizons nearly did.
|
| New Horizons didn't nearly overtake Voyager. It's currently
| traveling about 4 km/s slower, and as it's still closer to
| the Sun, it's also decelerating more.
| vikingerik wrote:
| Yes, I wrote that short for brevity. If you must have the
| full thing spelled out: New Horizons nearly got enough
| velocity at Jupiter to eventually overtake Voyager. 4
| km/s is "nearly" in astronomical terms. New Horizons
| wasn't really trying to optimize for speed at Jupiter
| (its closest approach was over 10m km), and a spacecraft
| that did could easily overtake Voyager using Jupiter
| alone and not need an alignment with Saturn or anything
| else.
| jfengel wrote:
| Even if we could there isn't much point. There just isn't very
| much out where the Voyagers are, and there won't be for a long
| time. We're shutting down sensors on Voyager because there just
| isn't much to see. It's just vacuum.
|
| If we had something capable of getting to Voyager in a year
| that might be worthwhile, because it would stand a chance of
| getting somewhere interesting in a few decades. But we are
| absolutely nowhere near that level.
| Denvercoder9 wrote:
| > We're shutting down sensors on Voyager because there just
| isn't much to see.
|
| That's not why Voyager's sensors are being shut down, they're
| being shut down because the probes no longer have the power
| to run them.
| downrightmike wrote:
| Not in our lifetimes
| vlovich123 wrote:
| > at much faster speed
|
| As others have pointed out, the speeds for Voyager 1 were
| because of gravity assist of Jupiter and Saturn while Voyager 2
| was a gravity assist of Jupiter, Saturn, Uranus and Neptune.
| Jupiter & Saturn line up relatively often enough so we could
| try to outdo Voyager 1 speeds a bit with a lighter air craft
| due to various advancements. But it's unclear we'd learn
| anything really new from having sensors that reached further
| out and our technology for propulsion really hasn't
| meaningfully advanced to outdo gravity assists from Jupiter +
| Saturn. There's some proposals to use nuclear explosions behind
| a probe to achieve speeds of ~10k km/s which would be
| substantially faster but there's numerous obstacles (cost +
| international treaties banning the use of nuclear in space).
| grvbck wrote:
| > let's say just couple of years ?
|
| Not a couple of years. The Voyagers have been doing around 38
| 000 mph since the late 1970's. That is rougly 17 km/s. The
| proposed Interstellar Probe mission aims to do 20 km/s or
| slightly more. It will take it decades to overtake any of them
| (no actual overtaking will probably take place though, as its
| trajectory most likely will be different).
| heresie-dabord wrote:
| > scientists and engineers back on Earth have increasingly had to
| deal with age-related maintenance issues
|
| There is perhaps unintended irony in that sentence, but it does
| evoke some Asimov stories in which human characters age while
| supporting technology.
| mannykannot wrote:
| I like this quote:
|
| "We didn't design them to last 30 years or 40 years, we
| designed them not to fail," John Casani, Voyager project
| manager from 1975 to 1977, says in a NASA statement.
| jfengel wrote:
| That doesn't seem helpful. Nothing lasts forever, and if you
| don't figure out when it's going to fail, it's going to be
| sooner rather than later.
| davidcbc wrote:
| Maybe the guy who helped launch the two manmade objects
| furthest from earth knows more about how to build space
| probes than you
| yodon wrote:
| >Nothing lasts forever, and if you don't figure out when
| it's going to fail, it's going to be sooner rather than
| later.
|
| You might be surprised about the reality of the situation.
|
| I had a professor who worked on the design and fabrication
| of the Apollo Guidance Computers, which likely was a
| somewhat similar process to the one being discussed here.
| It's been quite a few years since his lecture on it, but
| the process went something like this:
|
| They started with an analysis of the predicted
| lifetime/reliability of every chip type/component available
| to potentially include in the design.
|
| The design was constrained to only use components with the
| top x% of predicted life.
|
| Then they surveyed each manufacturer of each of those
| component types to find the manufacturer with the highest
| lifetime components for each of the highest lifetime
| component types.
|
| Then they surveyed the manufacturing batches of that
| manufacturer, to identify the batches with the highest
| lifetimes from that manufacturer.
|
| Then they selected components from the highest lifetime
| batches of from the highest lifetime manufacturers of the
| highest lifetime components.
|
| Using those components, they assembled a series of guidance
| computers, in batches.
|
| They tested those batches, pushing units from each batch to
| failure.
|
| They then selected the highest quality manufacturing batch
| as the production units.
|
| When he gave this talk, decades after the Apollo era, NASA
| had been continuing to run lifetime failure analyses on
| other units from the production batch, to try to understand
| the ultimate failure rate for theoretical purposes.
|
| Several decades after the Apollo program ended, they had
| still never seen any failure events in these systems, and
| shortly before the time of his lecture, I believe NASA had
| finally shut off the failure testing of these systems, as
| they were so remote from then "modern" technology (this was
| decades ago, hence the quotes around "modern").
|
| This is what happens when you have the best minds committed
| to designing systems that don't fail. Yes, the systems
| probably will fail before the heat death of the universe.
| No, we don't have any idea when that failure time will be.
| Yes, it's likely to be a very long time in the future.
|
| (And, of course, this is typed from memory about a lecture
| decades ago on events happening decades before that. This
| being HN, someone here probably worked on those systems, in
| which case hopefully they can add color and fix any defects
| in the narrative above).
| thebruce87m wrote:
| >This is what happens when you have the best minds
| committed to designing systems that don't fail.
|
| And a budget to support them.
| heresie-dabord wrote:
| A testament to requirements and quality. Thanks for
| sharing this insight, cheers!
|
| > This is what happens when you have the best minds
| committed to designing systems that don't fail.
|
| Given how times have changed, perhaps it is also valuable
| to note that other major-yet-unwritten factor:
| _confidence in the supply chain_.
| exmadscientist wrote:
| Incidentally, you have the question backwards: no one
| really cares when it's going to fail. We care when it's
| _not_ going to fail: will the spacecraft make it to its
| destination or not? It doesn 't really matter what happens
| after that.
|
| This might seem like a nitpick, but changes in approach and
| mindset like this are often the difference between success
| and failure with "impossible" problems like this. So it's
| critical to get your approach right!
| mannykannot wrote:
| I imagine there are cases which exemplify your point, but
| this does not look like one of them.
| NavinF wrote:
| FWIW his quote also applies to a lotta devices here on
| Earth. For example guns are not designed to last forever,
| but they are designed not to fail. You don't want to hear a
| click when you expect a bang or vice versa. As a side
| effect, they last forever. It's fairly common for a 100
| year old gun to work perfectly in 2024.
| xpe wrote:
| I would expect a mindful trade-off against total system mass
| and cost.
| metalman wrote:
| It's too bad this cant qualify as some sort of world record
| that_lurker wrote:
| Could be the start of space records :-)
| metalman wrote:
| I was struggling trying to think up any other plausible
| scenario, where one unit in a continiously operating piece of
| electronic /hard/soft ware was rebooted after such a long
| time and Voyager most likely has no competition in this
| regard or in a number of others sure speaks volumes for how
| well the nasa crew ,knew there stuff, and got it right
| durring that era,on budget,on time, and now doing inter
| generational space research making the actual designs and
| blue prints of the space craft, very much worth re
| examinining
| gruturo wrote:
| We have to way to know it it's actually the fastest and
| farthest object: A 1957 nuclear test was conducted underground,
| but the scientists decided to cap the borehole with a sizable
| concrete and metal plug.
|
| The nuclear explosion may or may not have caused said plug to
| reach space - the data from the cameras indicate it had at
| least 6 times the needed escape velocity, but it is difficult
| to estimate whether it would completely disintegrate or if
| enough of it would survive the atmosphere and whether it would
| "count"
|
| https://nuclearweaponarchive.org/Usa/Tests/Plumbob.html (look
| for Pascal-B)
| pupppet wrote:
| I didn't realize the Voyagers relied on a once in a 175 year
| planetary alignment. What a lucky break technology had advanced
| to the point we could make use of it.
| jmclnx wrote:
| And I remember the "crazies" saying the world will come to an
| end due to that alignment. That belief was reported in the main
| stream media.
|
| When it did not happen, I think they moved on to 2012 :)
| timthorn wrote:
| Ah, yes - The Jupiter Effect:
| https://www.goodreads.com/book/show/3400930-the-jupiter-
| effe...
| fwipsy wrote:
| Forward by Isaac Asimov? I'm surprised he would have his
| name associated with this.
| harrisi wrote:
| Not just any foreword, a pretty big endorsement. You can
| borrow the book from the internet archive to read the
| full foreword, but here's the last bit:
| And in the end, it turns out that something will happen
| in 1982 that just may-- No, no, read it for
| yourself. Read it carefully and you'll find it far more
| fascinating than the tale of any millionaire found
| stabbed in any library, locked or otherwise. And far more
| important, too especially if you live in California.
| ISAAC ASIMOV 17 April 1974
| grapesodaaaaa wrote:
| I'm trying to figure out why the alignment was so important.
|
| Wouldn't it be possible to get a gravity assist in any
| alignment - albeit just taking a little longer to ping-pong
| across the system?
| ericbarrett wrote:
| The alignment greatly reduced the amount of
| energy/propellant/weight to launch the Voyager missions with
| all four of the outer planets on the menu. Alignments that
| allow you to reach a smaller set of the outer planets with
| the same budget are more common: years or decades.
|
| (Edit) Another thought, since you mentioned time--numerical
| computing power and the math required to exercise it have
| advanced greatly since the 1970s, and it's likely that some
| of the trajectories and maneuvers feasible (again with the
| same fuel budget) today, even if they took 100+ years to
| complete, weren't even calculable back then.
| vikingerik wrote:
| The scenario where a gravity assist doesn't work is if
| turning sharply enough would require your minimum
| planetcentric approach distance to be less than the radius of
| the planet - you'd crash into it instead.
|
| This is why Voyager 2 couldn't also do Pluto - it would have
| needed to change course by roughly 90o at Neptune, which
| would have required going closer to the center of Neptune
| than Neptune's own radius.
|
| The most unusual gravity-assist alignment that we did was for
| Pioneer 11 going from Jupiter to Saturn. The encounters were
| separated by roughly 120o of heliocentric longitude. Pioneer
| 11 used Jupiter to bend its path "up" out of the ecliptic
| plane and encountered Saturn on the way back "down". Nowadays
| we wouldn't bother doing that (we'd wait for a more direct
| launch window instead), but the purpose of this was to get
| preliminary Jupiter and Saturn encounters done in time before
| Voyager's launch window for the grand tour alignment.
| westurner wrote:
| Could Voyager have reduced velocity, glanced off Neptune,
| waited for the return path on a narrow elliptical orbit,
| and then boosted to effectively make the 90deg turn to
| Pluto at that time? Was that impossible given its Neptune
| approach trajectory, or would glancing off and waiting have
| been more fuel?
|
| And, why didn't this vortical model that includes the
| forward velocity of the sun make a difference for Voyager's
| orbital trajectory and current position relative to earth?
| https://news.ycombinator.com/item?id=42159195 :
|
| > _" The helical model - our solar system is a vortex"
| https://youtube.com/watch?v=0jHsq36_NTU _
| vikingerik wrote:
| Breaking that down: Voyager itself couldn't have reduced
| velocity, it had nowhere near enough reaction mass to do
| that. Hypothetically a spacecraft could but you might be
| talking about orders of magnitude more reaction mass.
| (Which means multiples more of the fuel to launch and
| accelerate that mass itself, which could quickly escalate
| beyond any chemical rocket capabilities.)
|
| It also likely wasn't possible to get to Pluto on some
| future Pluto orbital pass. The limiting factor is likely
| that Voyager's incoming trajectory to Neptune was already
| too far beyond solar escape velocity to get into that
| narrow elliptical orbit you propose. (You'd have to
| slingshot so close to Neptune's center that you'd hit the
| planet instead.)
|
| Designing from the beginning to come in slower to Neptune
| and adjust to encounter Pluto on some future Pluto
| orbital pass was probably possible, but yeah you might be
| talking about time scales of Pluto's entire orbit or even
| multiples of that. (We do similar things for inner solar
| system missions, like several encounters with Venus
| separated by multiple Venus-years, but that's on the
| order of single-digit years and not hundreds.)
|
| The common answer to a lot of these outlandish slingshot
| questions is usually, yes it's eventually possible by
| orbital mechanics, but it gets so complicated and lengthy
| that you may as well just build another separate
| spacecraft instead. We talk about Voyager's grand tour
| alignment because it's captivating, but realistically if
| that hadn't happened we would have just done separate
| Jupiter-Uranus and Jupiter-Neptune missions instead.
|
| The sun's motion relative to the galaxy doesn't matter
| for any of this - nothing else in the galaxy is remotely
| close enough to affect anything, the nearest star is
| still over 1000x Voyager's distance.
| downrightmike wrote:
| Speed run hacking
| exmadscientist wrote:
| The alignment was important because it allowed visiting four
| planets with one spacecraft. So you only had to launch one
| spacecraft. (We launched two anyway.)
|
| If you are willing to launch four spacecrafts to visit four
| planets, the alignment restrictions are much relaxed. You do
| need to be careful about your launch window to get a nice
| boost, but it's measured in years between windows, not so
| much centuries.
| Sharlin wrote:
| No, there's no pingponging. There's only _so_ much momentum
| you can exchange with a planet, because there 's only _so_
| close a flyby that you can make before it stops being a flyby
| and becomes a fly-into.
| relistan wrote:
| Ignoring the feasibility of the physics, imagine trying to
| calculate all the resulting trajectories to point antennas at
| to talk to the probe. With computers and equipment of the
| 1970s.
| kibwen wrote:
| It wasn't just a lucky break, it was the result of furious
| efforts by scientists to lobby years in advance to take
| advantage of the alignment, as well as engineers who repurposed
| two Mariner probes to save money, as well as canny NASA
| bureaucrats who sneakily downplayed the possibility of a full
| Grand Tour in order to reduce estimated costs (with the full
| intent to underpromise and overdeliver, which Voyager 2
| successfully did by "coincidentally" being on course to visit
| Neptune and Uranus after completing its primary mission to
| Jupiter and Saturn (to this day, Voyager 2 remains the only
| visitor to Uranus and Neptune)).
| bigiain wrote:
| Still a huge amount of luck involved. If that planetary
| alignment had happened even 10 years earlier NASA probably
| wouldn't have had the capability to do anything with it. If
| it had been sometime recently, say after the Challenger
| disaster, I doubt it would have got funding...
| jonplackett wrote:
| Were engineers 50 years ago just much smarter than we are now?
| It's pretty unbelievable that these things still work. Or is
| there something systemic about how they were able to achieve so
| much so long ago with basically no computers to help.
| arcbyte wrote:
| There was much less overall complexity (and capability). These
| engineers interacted directly with capacitors and circuits to
| accomplish their tasks. Integrated circuits enable a lot of
| modern society, but it also segregates engineering between
| fabrication time and everything afterwards.
| jonplackett wrote:
| I find that more analogue / mechanical type machines even
| more amazing in someways. Like how they say it 'decided' to
| switch to its backup radio. How are those decisions made on
| such basic hardware? I guess thinking mechanically is just a
| very foreign concept for me mostly making software
| avereveard wrote:
| They had lot less resources and knowledge to estimate the right
| amount of resilience for achieving the mission goals and erred
| on the side of cautions.
|
| You can see something similar happening in bridges, weight per
| meter load has come down considerably since the 60s because
| material understanding is much more advanced and they meed less
| margin for the same safety factor.
| soulofmischief wrote:
| Our understanding of physics has also gotten much better, for
| example our understanding of tensegrity.
| https://en.wikipedia.org/wiki/Kurilpa_Bridge
|
| > The Kurilpa Bridge is a multiple-mast, cable-stay structure
| based on principles of tensegrity producing a synergy between
| balanced tension and compression components to create a light
| structure which is incredibly strong.
| liamwire wrote:
| Delighted to see this here -- the Kurilpa Bridge is less
| than 50 meters from my front door and is something to
| behold each time I get the chance to use it.
| kamma4434 wrote:
| Golden NASA budgets might have helped...
| jdthedisciple wrote:
| They weren't affected by DEI nonsense yet.
| emchammer wrote:
| It's not nonsense. Many of the radio receiver setups made use
| of diversity or dual-diversity configurations. Also,
| transmitter and receiver blocks from different manufacturers
| were wired in switchable primary/backup configurations.
| ReptileMan wrote:
| >Were engineers 50 years ago just much smarter than we are now?
|
| Were the 2006 sony santa monica programmers smarter then us
| when they delivered God of War 2 for the PS2 on its tiny
| resources?
|
| Usually the constraints force you to become inventive and
| smart. Put a hard limit of 128 mb per tab on web browsers and
| suddenly both the developers of the browsers and the web
| developers will become extremely smart.
|
| The over abundance of resources has made the majority of
| software engineers lazy. If we once again live in scarcity
| times - suddenly people will start to ask why we need 8
| abstraction layers to do something.
|
| I would guess they were quite smart bunch, but no superhuman -
| just people tasked with extremely challenging task, trying to
| jury rig something on the edge of possibility. My guess is that
| they took their tasks more seriously and to heart.
| jccooper wrote:
| NASA missions still routinely overperform. Curiosity's been
| operational on Mars for a good 12 years now.
| Tempest1981 wrote:
| Worth a watch, imo:
|
| _It 's Quieter in the Twilight_
|
| https://www.space.com/nasa-voyager-mission-engineers-documen...
|
| Interesting trying to manage their declining power budget. And
| decipher docs written 40+ years ago.
| gdubs wrote:
| I'm reading Pale Blue Dot to my kids at night currently so this
| is really awesome. (The Voyager missions are described in
| excellent detail in ways that I never appreciated fully before.)
|
| It blows my mind that these are machines from the 8-track era.
| And they have fallbacks and redundancies that were completely
| ahead of their time.
| leobg wrote:
| Cool! I do the same thing with books like Asimov's Earth and
| Space (science) or Lois Lowry's Number the Stars (fictional
| history). What other books can you recommend?
| gdubs wrote:
| Good question but I have a fever at the moment so
| unfortunately my brain is not fully functioning :/
| Salgat wrote:
| NASA loves to downplay expectations in case something goes
| wrong, but people really underappreciate just how
| overengineered these things are, which makes sense when a bad
| mission can be political suicide for their future funding.
| gdubs wrote:
| It was also incredibly on budget. I think Sagan says in the
| book it cost the individual American taxpayers in the single
| digit dollars.
| noselasd wrote:
| Single digit dollar sounds more like the Appollo program. I
| think it's been a _long_ time since the entire NASA budget
| was more than a penny per tax dollar.
|
| NASA says the voyager mission cost 865 million dollars from
| the start in 1972 to Neptune encounter in 1989, and
| currently runs at 7 mllion dollars per year.
| stevenwoo wrote:
| One feels a terrible disappointment Sagan didn't live to see
| the future mission projects he talks about in the book get
| finished and most of them succeeded IIRC. By happenstance the
| 2024 Solar System BBC series mostly uses animation but has some
| real photos and videos to document a lot of happened since the
| book was published.
| isosphere wrote:
| The last time I read Cosmos I hit the part about the Cassini-
| Huygens mission where he wondered what we might find under
| the atmosphere of Titan, and was able to immediately just
| find out.
|
| I imagine a lot of people who work on space missions do not
| outlive their work - which feels sad but also ... inspiring?
| wkat4242 wrote:
| Yeah it's really amazing that these come from a time where
| normal people had never even heard of bits and bytes. And now
| they're the furthest man made objects and their data link still
| works.
| ghoomketu wrote:
| It's fascinating how Voyager 1, despite my lack of space
| knowledge, utilizes a nuclear power source for 40+ years,
| offering steady and reliable power without any moving parts that
| could degrade over time.
|
| In contrast, India's decision to rely on solar panels led vikram
| lander to be dead in just 14 days due to lack of sunlight
| (afaik).
|
| I'm curious about the rationale behind this choice when nuclear
| power seems like a far superior option. Can someone shed light on
| this decision?
| selectodude wrote:
| Using plutonium works great but there are two issues. 1) they
| don't output that much power. Few hundred watts at most, and
| they decay at a fixed rate. 2) you need to get your hands on a
| decent amount of plutonium. Great for dirty bombs, hard to
| source.
| floatrock wrote:
| Isn't it something like space-reactor plutonium is a waste
| product from nuclear weapons production, and since we don't
| really make nuclear weapons at scale anymore, we aren't
| really making (refining?) plutonium anymore. And NASA has
| some amount on reserve, but they're rationing it out
| carefully. So the Clipper probe had to go with a massive
| solar array (100ft, the length of a basketball court) because
| they would rather save their plutonium for some future rover
| mission.
| nick__m wrote:
| it don't make sense to stock hot plutonium to use it later,
| it loose power and decays overtime wherever you use it or
| not!
| TkTech wrote:
| Both Canada and the US have restarted production specifically
| to produce RTGs for NASA, but the process takes time to scale
| up and automate. It's gone up 4x in 4 years and continues to
| increase, so this is a problem that will eventually be
| "fixed".
| krger wrote:
| > I'm curious about the rationale behind this choice when
| nuclear power seems like a far superior option. Can someone
| shed light on this decision?
|
| India's plutonium has already been spoken for.
| jordanb wrote:
| A good reason is the lack of availability of the needed isotope
| (Pu238).
|
| The Europa Clipper has a huge array of solar panels instead of
| an RTG due to the last of the available supply going into the
| New Horizons spacecraft.
|
| Pu238 was a cast-off isotope from nuclear weapons development
| so it was more readily available during the cold war. We should
| be happy that it's scarce now.
|
| Also solar panels have gotten a lot better than they were when
| Voyager was launched, but even today anything going out past
| Saturn is not going to be able to use solar energy.
| wffurr wrote:
| There was just an article about a whole array of "nuclear
| batteries" using all sorts of decent chemistry:
| https://news.ycombinator.com/item?id=42118306
|
| Are any of those candidates or are they just too small or
| with too poor a mass ratio compared to plutonium RTGs?
| YakBizzarro wrote:
| Availability :) a RTG requires Plutonium 238, which needs to ne
| created almost on purpose in a nucleare reactor. Not all
| nations have this ability or they are running such expensive
| programs. Also in the USA they are reserved for programs where
| there is very little light available
| augusto-moura wrote:
| I don't know the exact reasons why Vikram didn't get a fission
| reactor. But I can assume from similar missions:
|
| 1. Solar is pretty good as far as Mars and it gets worse as it
| travel further from the Sun. This is why most probes that
| travel past Mars need a nuclear reactor (Voyager, Pioneer,
| Cassini, etc). Going closer to the sun they get even better
|
| 2. Sending radioactive materials on rockets presents a risk and
| it is avoided if possible, lunar probes are usually cheaper and
| can still benefit from solar, so no need for nuclear. Imagine
| throwing plutonium in the atmosphere in the case of an accident
|
| 3. Nuclear reactors in probes are small and rely on decay
| radiation, they _usually_ have pretty small powet output, solar
| has a lot
|
| 4. And last but not least, price, solar is much cheaper than
| nuclear
| mmooss wrote:
| > fission reactor
|
| Am I wrong that the plutonium in the Voyagers is not in a
| fission reactor but in an RTG (Radioisotope Thermoelectric
| Generator), which converts the heat from the plutonium into
| electricity. ?
|
| I suppose the heat is result of fission, but I don't think an
| RTG is what is meant by a fission reactor. ??
| Vecr wrote:
| Voyager uses a RTG. The USSR used some full-on nuclear
| reactors in space, but as far as I know no one else
| publicly did.
| joeyo wrote:
| The US put a fission reactor in space too. They did it
| first, in fact: https://en.wikipedia.org/wiki/SNAP-10A
|
| Edit: it's apparently still there and will be for a long
| time (!) albeit non-functional: > Decay
| date: April 3, 5966 (planned)
| datameta wrote:
| Dead in 14 days? Was there a miscalculation that lead them to
| believe they could make one full night?
| freeone3000 wrote:
| Sure!
|
| First, the nuclear power source is a giant hunk of plutonium.
| It is expensive to get, dangerous to use, and due to concerns
| about further refinement, is restricted internationally.
|
| Second, it is toxic inherently -- the source is continuously
| radioactive at a hazardous level to humans, plutonium itself
| has acute and long-term toxic effects aside from the
| radioactivity, and if a launch fails, the rtg will disintegrate
| and poison hundreds of miles (see Kosmos 954, which
| disintegrated over Canada)
|
| Third, it is HEAVY. They produce 40W per kilogram. Solar panels
| produce three times that much on Mars, and can be folded
| compact for launch.
|
| Voyager used an RTG because its planned mission took it far
| beyond where sunlight can generate power, and it could do so
| because it had the budget of NASA and plutonium from the
| Department of Energy.
|
| Solar panels are way cheaper, lighter, easier to procure,
| easier to launch, and tend not to cause international
| incidents.
| Salgat wrote:
| I wonder if you could do a hybrid approach, where the nuclear
| device is very small, but able to charge the battery over a
| longer duration to the point where the solar panels can be
| repositioned and utilized again.
| mlyle wrote:
| Lots of missions use radioisotopic heaters, where you don't
| bother with the thermocouples and just have the material
| get warm and protect components which are vulnerable to low
| temperatures.
|
| That's the main reason why spacecraft don't survive a
| temporary power outage: terrible environmentals.
|
| But at this point, we don't have a lot of Pu-238, which is
| one of the only decent candidates.
| jojobas wrote:
| Kosmos-954 didn't poison hundreds of miles, square or
| otherwise.
|
| They could only find a dozen of radioactive bits, each only
| dangerous within a very small area around it, and not really
| leaching anything due to its ceramic nature. Most of the fuel
| dispersed and became harmless by dilution, probably never
| even reached the surface.
| pkaye wrote:
| RTGs need plutonium 238. I've read even US doesn't have a lot
| available. The Europa Clipper will be using solar panel for
| example. India could also use batteries and a standby mode
| during the 14 days without sunlight. But any extra weight would
| add to the launch cost. Maybe in future missions as they get
| confident with successful landing, they will have bigger lander
| that can survive the lunar night. Even the early Mars rovers
| from NASA were tiny and solar powered (ie Sojourner in 1997.)
| elzbardico wrote:
| India is a nuclear armed-nation with some long-standing border
| tensions with some of their also nuclear-armed neighbors.
|
| The military probably have priority on the decisions about the
| allocations of their plutonium stocks.
| kvemkon wrote:
| Discussed earlier:
|
| "NASA reconnected with Voyager 1 after a brief pause"
| (30.10.2024)
|
| https://news.ycombinator.com/item?id=41992394
| ck2 wrote:
| Imagine 100 years from now they come up with a probe engine that
| can get to 10% the speed of light, it would only take a month to
| reach Voyager.
|
| Even at only 1% it would take under a year, but lots of
| breakthroughs needed for even that.
| WalterBright wrote:
| Now that we've got SpaceX cheap launches, it's time to launch a
| fleet of solar system probes and space telescopes.
|
| Why isn't this happening?
| teruakohatu wrote:
| See Three Body Problem (the books)
| tliltocatl wrote:
| AFAIK launch vehicle cost were never the problem for deep space
| probes. Launch windows still are - Voyager was extremely lucky
| in this regard. And then there is probe design and construction
| - SpaceX made launches cheaper, but that just shift most of the
| cost into the payload. And then there is no point in having
| such a fleet if you there isn't enough funding for scientists
| to process the results.
| WalterBright wrote:
| Most of the probes would be identical. Building two identical
| probes would cost only marginally more than 1, perhaps 10%
| more.
|
| > but that just shift most of the cost into the payload
|
| It reduces the cost, not shift it.
|
| > And then there is no point in having such a fleet if you
| there isn't enough funding for scientists to process the
| results.
|
| Plenty of funding would become available if the funding for
| junk science stops, such as:
|
| "In 2021, the National Institutes of Health (NIH) awarded
| $549,000 to a Russian lab performing experiments on cats,
| including removing part of their brains and seeing if they
| could still walk on treadmills, according to the Washington
| Times." https://nypost.com/2024/11/13/us-news/where-elon-
| musk-can-st...
| mmooss wrote:
| > Most of the probes would be identical.
|
| Is there some existing plan? A paper that supports this
| idea? It's not clear to me that the probe we send to one
| place for one purpose is the same we'd send to another.
|
| > Building two identical probes would cost only marginally
| more than 1, perhaps 10% more.
|
| I've read from experts - somewhere here on HN - that isn't
| how the costs work.
|
| > Plenty of funding would become available if the funding
| for junk science stops, such as
|
| > "In 2021, the National Institutes of Health (NIH) awarded
| $549,000 to a Russian lab performing experiments on cats,
| including removing part of their brains and seeing if they
| could still walk on treadmills, according to the Washington
| Times." https://nypost.com/2024/11/13/us-news/where-elon-
| musk-can-st...
|
| $500k is not enough to matter for a space probe, and I
| don't see why that brain research is junk science. If you
| truly think the research was about half-brained cats, then
| you really should appreciate that research. :D
| mmooss wrote:
| Isn't most of the cost due to designing and building the
| probes? One launch has been routine for NASA (and others) since
| long before SpaceX.
| tunnuz wrote:
| This stuff will never not blow my mind.
| renegade-otter wrote:
| That thing just won't die!
| bilsbie wrote:
| I'm not saying it's true but I really feel like I see this
| article once or twice a year. I'm not sure what's going on.
| xanderlewis wrote:
| I think there've been at least two recent episodes of trouble,
| including this one. I feel like I've seen more than two
| articles about it though.
___________________________________________________________________
(page generated 2024-11-17 23:00 UTC)