Voyager is probably the most badass awesome thing ever.
Every single aspect of space travel is an engineering/mathematic/scientific marvel. Not only did we plan, build, launch these, (before I was born) but we're still communicating (until we can't).
I'm reading links people have posted here, trying to understand how we communicate with these probes. It's fascinating.
What I find more amazing is the fact that a lot of what could be referred to as "space-age technology" is actually many decades old, and thus was accomplished with a fraction of the processing power and knowledge we have today. Voyager was launched in the late 70s, but based on technology of the 50s and 60s. We visited the Moon almost 50 years ago, using that technology.
If you look at old spacecraft hardware, one thing that stands out is its apparent simplicity and down-to-earth (no pun intended) design --- and I'd argue that this is at least partially responsible for its extreme reliability.
From that perspective, I feel as though developments in modern technology just can't compete for impact; we constantly search for new ways of designing things, wrapping ourselves in endless layers of abstraction and high-level thought, yet aren't really "getting off the ground" and accomplishing something concrete, so to speak.
From that perspective, I feel as though developments in modern technology just can't compete for impact; we constantly search for new ways of designing things, wrapping ourselves in endless layers of abstraction and high-level thought, yet aren't really "getting off the ground" and accomplishing something concrete, so to speak.
I’m not really sure this is true, though I understand why it might feel that way sometimes.
I’m currently travelling at about 180mph on board a high-speed train in Japan. I flew here on a jet which is something like 20% more efficient than the equivalent from a few years ago. Using the ubiquitous LTE network, I can make a real-time HD video call to my family back in the UK, using my palm-sized, battery-powered computer. I used the same device earlier to do some research about cities as we passed through them, and also to check the CCTV system at home. Over the past couple of weeks I’ve used a similar technology stack to locate my position to meter-level accuracy, to read and translate foreign language text from images in real time, and to record hours of 4K video.
Modern technology is astonishingly powerful - and in some ways, the examples I described above are even more impactful to me on a day-to-day basis than space exploration is. Don’t get me wrong - the latter is still important and exciting! But it’s sometimes too easy to forget the impact of the somewhat more mundane technology that’s all around us.
>I’m currently travelling at about 180mph on board a high-speed train in Japan.
Which is also (high speed trains) an 30+ year old technology, even if the train you're on was built more recently.
That's what the parent means about those older technologies having more impact. Which is trivially true: earlier low hanging fruits give substantially more bang for the back to progress, and then you get incremental progress and finally marginal returns on any technological fields.
The airplane was a huge development. The modern commercial airliner (50+ years old by now) as well. A jet "which is something like 20% more efficient than the equivalent from a few years ago"? Not so much.
>Using the ubiquitous LTE network, I can make a real-time HD video call to my family back in the UK, using my palm-sized, battery-powered computer.
Which again, compared to the initial impact of the internet and mobile communications it's just an incremental improvement. Being able to send messages and talk from Japan to the UK instantly -- great impact. Being able to send HD video on top of that? Not so much.
I agree that LTE/HD is incremental. It's probably fair to say that ubiquitous mobile smartphones are something more. (Initial mobile communications less so. When I had a feature phone I often didn't even carry it with me although certainly some people probably found them more transformational.)
But they're different systems, designed very differently. A high speed train and a space craft are both designed carefully to maximize their possible life. A cellphone is, unfortunately, been phased into the economy of consumption and planned obsolescence.
Consumer electronics from a few decades are not quite cellphones, but not quite high speed trains or nuclear reactors or space rockets. Many old C64 systems still work or can be restored, and I bet most of our current high end laptops will continue to work a decade from now (you might need to replace the battery).
The OP might have been talking about efficiency, and we have gotten a bit sloppy with that in the consumer world (why does Slack/Atom/Discord need to be a 100MB+ app bundled with its entire web browser and framework? It's like we're in the 2000s with 15 copies of the JDK on your system again!), but once again .. different uses.
A modern SpaceX craft is going to have custom real time operating systems designed specifically to preform much more complex calculations than we've done in previous space missions, hopefully increasing reliability and the amount of sensors we can read, record and transmit data for. The software engineers might be less space efficient in their code than the previous generation, but if the hardware is cheaper and we can increase readability at the expense of memory, why not do it?
In Kim Stanley Robinson's Mars trilogy (highly recommend; best Sci-Fi I've ever read), humans eventually create AI so complex it can manage space factories designed to build from asteroids. The most advanced AI ever created is used to maneuver an asteroid into orbit of Mars while also mining the interior and constructing the cable that would eventually turn into the space elevator over the course of a decade.
The reliability of these systems is indeed quite impressive, yet it simply isn't a requirement for most of our day to day equipment. OTOH some heavy duty machinery can be very reliable.
We always building on what was previously there so one can make that argument for almost about anything.
But we've definitely made progress on a number of things. My rav4 although a lot more complex than Toyotas of 30 years back is a lot safer and efficient.
Focused human attention is still by far the most powerful optimization device we have.
AI hype notwithstanding, no machine learning comes even close -- it's generally a parameter search in a space that's too pedestrian, leaving the real hard work (defining the problem context, goals / objective function, viable tradeoffs and shortcuts) to the human.
Cute AI demos aside, when reliability comes knocking on the door, you end up looking for ways to simplify or avoid the whole bloody mess.
If you spend the time to understand the problem well enough (as you must with space tech), the number of degrees of freedom aka model parameters shrinks. Then suddenly computing power and large-scale parameter searches don't buy you as much; their trade-offs against increased complexity aren't as appealing.
"With four parameters I can fit an elephant, and with five I can make him wiggle his trunk." -- John von Neumann
I've lived through a couple of design reviews for flight software and hardware, and I can tell you this is spot on. The emphasis is on minimal delta from previous products, absolutely nothing remotely risky, and complete assurance of functionality before launch.
Have you heard of the Opportunity Rover? I believe it has outlasted its designed lifetime a few times now. Also, its still operational.
The only way we can even contact Voyager is the fact that we have better radio signal processing on earth and that has been improving since we launched Voyager.
>What I find more amazing is the fact that a lot of what could be referred to as "space-age technology" is actually many decades old, and thus was accomplished with a fraction of the processing power and knowledge we have today.
Yes, but then they weren't using it to power immense social networks with pictures of people's food.
Both Voyagers are still collecting magnetic/plasma field and radiation data (only Voyager 1 is in interstellar space, Voyager 2 hasn't made it yet). Mostly they are measuring the outer edges of the Sun's magnetosphere as it interacts with interstellar space, and it's a dynamic phenomenon so the data is actually more interesting than you might imagine. Several research papers a year continue to come out of the missions.
tl;dr: it's not clear what defines the edge of the solar system, there's interesting reasons to want to know where it is, and voyager taught us a lot about it.
For anyone with an interest in Voyager, I highly recommend Emer Reynolds film, "The Farthest". This documentary is brilliant, beautiful, and funny - and I guarantee that you will learn something that you didn't know about Voyager!
For those in the UK, it's currently streaming on iPlayer - though it should ideally be seen in cinemas to be fully appreciated.
> "The Voyager flight team dug up decades-old data and examined the software that was coded in an outdated assembler language, to make sure we could safely test the thrusters," said Jones, chief engineer at JPL.
I'm curious as to what they mean by 'outdated.' Is the actual language outdated or simply the architecture? I would assume the latter, but it's tough to tell. I just can't figure out how assembly could become outdated.
Each processor has its own instruction set and thus assembly. Further, there are various assembly syntax dialects that can fall in and out of use. For example, the AT&T syntax and Intel syntax used for x86: https://en.m.wikipedia.org/wiki/X86_assembly_language#Syntax
But they should be .. or at least last as long as an old C64. You can put newer Windows on pretty old hardware, and for really old hardware you can always slap Linux on and it will still be useful. There are still Kernel forks to support 386 processors!
Cellphones are a mess because we can't even have a nice base hardware platform. ARM isn't a platform. It's a SoC spec with random shit soldered to random pins by different vendors with completely non-upstreamable kernels. Google could just mandate UEFI on OHA phones like Microsoft did with theirs, but instead we're just getting this /vendor partition in the next release.
I don't think it's unintentional either. It's an aspect of planned obsolescence. The cellphone industry wants you to upgrade every two years, when we should not be destroying the planet and creating gear that lasts 10 years. Fewer factories, less pollution, longer life .. but we're in a consumerist economy hardwired the opposite direction, where any type of profit shortfall or lack of growth is seen as a problem, not the result of a good product.
Agreed, but if a public company makes stuff to last 10 (why not 20) years then they'll go bust because capitalism requires profit and sustainable ideals are contrary to profit.
What we need is a privately held cellphone company that will forgo profit in favour of creating long lasting, repairable, maintainable devices. [I've been working on this thesis for the transition from capitalism to communism]
Meanwhile I'm wearing a 25 year old tshirt, whilst tshirts bought much more recently wear out and get holes in.
Instead, was designed to last only as long until the next induced appetite for a new phone. Cuz otherwise, financials wouldn't look as good while another company X in the industry capitalizes on it anyways
NASA usually has a duplicate system (full mechanicals, not just a simulation) to test things on to make sure they don't create a brick. NASA can also use the dupes as a backup in case there is an accident during launch and the first system gets destroyed.
This assertion is correct for the more recent robotic missions (Mars Science Lander, Mars Exploration Rovers (MER), Mars Pathfinder/Sojouner) but I don’t recall seeing or hearing about spares for earlier missions or satellite/spacecraft-based missions. Earlier missions would probably have had only an empty mechanical flight spare. I worked in the Spacecraft Assembly Facility at JPL and was very familiar with the Technical Inventory Management team (the group that managed storage and logistics for reusable and non-reusable technology assets).
Generally speaking, we built at least 3 versions (4 versions depending how you count).
1) Flight. The one put in the payload.
2) Flight spare. Often used in one of the 2 or 3 Mars test facilities at (the 2 Mars yards or simulation facility) and hooked up to a spare Ground Data System (controller system) via a 6 inch thick, 100 foot long “umbilical cord”.
3) A mechanical flight spare. A usually 80-90% mechanically accurate version that we called Bubba (at least for MER) that we’d pull out for Open House, or other special events and displays.
4) Lastly, I personally worked with subsystem flight spares (44u rack of the Satellite Communication Subsystem or the Flight Control System). Way too big to fit in a spacecraft in this configuration or a mock-up of the system.
What might be a more interesting story is how we bought dozens and dozens of old SUN pizza boxes and Sparc Stations in the mid and late 2000s from eBay (literally) in order to be able maintain the Flight Ground Data System.
The point really isn't to make sure the valves work (the environment might have broken them after a few decades in space), the point is to make sure the code you're uploading doesn't brick the computer. It's nice to have an original computer and fully replicated signal path to make sure there aren't any unforseen bugs. Emulators have a tendency to have 99% coverage but the missing 1% is what would cause us to throw an expensive brick out of the solar system.
They can not only be remotely upgraded, but remotely reprogrammed to avoid bad bits. 1970s computers were primitive by our standards, but not that primitive.
In the Epilogue of "Murmurs of Earth" (1978), Sagan writes:
"It is a difficult computer task to calculate what stars might by chance be along the Voyager spacecraft trajectories 50,000 or 100,000 years from now. Mike Helton of the Jet Propulsion Laboratory has attempted to make such a calculation. He calls attention in particular to an obscure star called AC+79 3888, which is now in the constellation of Ursa Minor -- the Little Bear, or Little Dipper. It is now seventeen light-years from the Sun. But in 40,000 years it will by chance be within three light-years of the Sun, closer than Alpha Centauri is to us now. Within that period, Voyager 1 will come within 1.7 light-years of AC+79 3888, and Voyager 2 within 1.1 light-years. Two other candidate stars are DM+21 652 in the constellation Taurus and AC-24 2833 183 in the constellation Sagittarius. However, neither Voyager 1 nor Voyager 2 will come as close to these stars as to AC+79 3888.
"Our ability to detect planetary systems around other stars is at present extremely limited, although it is rapidly improving. Some preliminary evidence suggest that there are one or more planets of about the mass of Jupiter and Saturn orbiting Barnard's star, and general theoretical considerations suggest that planets ought to be a frequent component of most such stars.
"If future studies of AC+79 3888 demonstrate that it indeed has a planetary system, then we might wish to do something to beat the odds set by the haunting and dreadful emptiness of space -- the near certainty that, left to themselves, neither Voyager spacecraft would ever plummet into the planet-rich interior of another solar system. For it might be possible -- after the Voyager scientific missions are completed -- to make one final firing of the onboard rocket propulsion system and redirect the the spacecraft as closely as we possibly can so that they will make a true encounter with AC+79 3888. If such a maneuver can be effected, then some 60,000 years from now one or two tiny hurtling messengers from the strange and distant planet Earth may penetrate into the planetary system of AC+79 3888."
We know so much more about exoplanets today than we did in Sagan's time, and have so much more computing power to bring to bear. Knowing the trajectory thrusters still work, it would be a fitting tribute to try one last interstellar bank shot into the corner pocket, and see if we couldn't honor Sagan's last wishes, and give the Voyagers a destination worthy of their journey and their cargo.
I could easily be wrong here, from the article it sounds like the remaining power reserves are only enough to correctly orientate Voyager to allow for its communications link to be pointing towards Earth.
If so and Voyager only has enough power to do some minor rotations of the probe for three more years it's unlikely that there is enough power to actually change its overall trajectory, even if fired all at once.
BTW thanks for your comment, it was nice to hear Carl Sagan again :)
Very likely there won't be humans in the next 100 to 500 years, assuming any reasonable rate of progress. Humans will quickly change themselves biologically, technologically, we are going transhuman.
That's very optimistic. There are are two pretty likely outcomes: humans will solve our problems, bring about peace, colonize Mars and voyage out into space ... or... we go extinct. We might waver between tech and stoneage for a bit with some war, but eventually we're likely to converge on one of those two.
Looking at humanity today .. I'm thinking we'll go extinct. Love your loved ones. Don't spent too much time in the office. Life is too short to not really live, cause there's a good chance literally no one will remember us a million years from now.
At the end were just apes with super computers. 100-500 years is not a long time.
The fact that ohur president in 2017 constantly throws out threats of nuclear war on a mass communication platform and yet has a sizable support says humans are fundamentally flawed. Just needs a few bad actors at the top and we'd be over.
Can somebody with knowledge of radio communication explain how we are able to send a radio signal to a destination that is 21 billion Kms away? How powerful does the signal need to be? What kind of technology is used to generate such a powerful signal?
It's mostly a function of how well your antenna is able to amplify the signal, how precise you can aim that antenna and how slow you transmit. If you have a very good antenna with lots of gain and a very precise mechanism of aiming it (at an object whose location is very well known, and Voyager is a moving target) it will take much less power than if either one of those elements is not optimal.
The idea here is that any radio energy that does not end up in the vicinity of the target was wasted and at 21 billion Km that gives you plenty of opportunity for mis-alignment.
Receiving the signal has similar challenges, with the added complication that this time the sender is sending with a power level that puts its signal under the noise floor by the time it reaches Earth.
Fun fact: this goes for the GPS satellites as well by the time their signal reaches your pretty little hand-held receiver and it takes nothing short of magic (to me, not to the people that design that stuff) to recover the signal.
If we launched a proxy satellite into the solar system to help communicate with these probes, would it make things easier/better? Or is it better to just communicate directly from the Earth?
For Voyager-like mission profile building useful network of such data relay satellites/probes would be prohibitively expensive.
For missions where that makes sense (mars probes, STS, ISS and IIRC even original Apollo moon landings) relay satellites or even networks of them are/were used. To some extent for such constructions to be useful it has to be constructed of satellites that orbit something which is near to target of the probe, which is impractical for probes that are on highly eliptical orbits around sun, not to say probes that are on exit trajectory like Voyager.
See the other thread :). Such satellite would need impractically large Rx sensitivity and Tx power. Doing that on surface of earth is simpler and significantly cheaper.
I think it would make things worse, the only advantage I see is that if you got it to work at all you could do away with the requirement that you'd need three base stations on Earth. A single Geostationary satellite should be able to keep both the base station and the Voyager in sight at the same time. But that's a lot of money to spend for very little advantage.
There is no launch vehicle that is capable of launchibg anything remotely similarly sized as typical DSN antenna, not to mention of similar mass. Also station and attitude keeping of such an satellite would be non-trivial problem at sufficiently high orbits for such thing to be useful.
Edit: TLDR: for the amount of money required to design, build and deploy such relay satellite in geosynchronous or such orbit you can do several manned missions to mars or some other planet of your choosing
It would not nearly have to be as heavy as it would have to be on Earth (no gravity to withstand so skeletal build will do just fine) and a 20KW transmitter could be powered on a satellite with relative ease. There have been quite a few proposals for antennae that unfold in space.
As for your edit: very heavy satellites cost (including launch) ~$250M whereas a manned Mars mission is estimated to cost $6B.
I really don't see how you could do 'several manned missions to Mars or another planet of your choosing' for the same budget as a single relay satellite, even a large one.
The problems I see with such a design are simply that it does not give you any advantage for spending all that money and actually stands a fair chance of making things worse. More stuff, so more stuff that can go wrong and if it does it is in a place where you can't fix it. Limited life-span as well compared to the Voyager itself because of the larger complexity (must keep two antenna's aimed at the same time while moving itself).
Unfolding some lightweight structure is certainly possible, but the attitude-keeping requirements are harsh.
Uplink path of DSN is capable of significantly higher power levels than 20kW, several orders of magnitude more. Also the whole transceiver electronics are especially fiddly, with various cryogenically cooled and/or high-power microwave valves without meaningful solid-state replacements, which is not something you want to have in GSO without any chance of mainteance.
> but the attitude-keeping requirements are harsh.
Yes, that's exactly what I wrote upthread, that's the hard requirement. And that is what will fail and then you've got a very expensive doorstop in an orbit outside of any repair capability. Inability do do maintenance / repairs is the killer.
My point was that the actual payload is mainteance-heavy.
On the other hand it is certainly true that RCS of such satellite would require exceedingly large stores of RCS supplies which will invariably run out and have to be somehow replenished.
Edit: even hall thrusters require stores of xenon and with the precision required the amount consumed is far from practical.
There are high gain antennas on both ends, and use of error correcting codes, as well as extremely high grade low noise amplifiers on the Earth side.
The Voyagers have a 3.7m diameter parabolic radio dish, larger than the Hubble space telescope's mirror even. That alone provides a huge amount of gain on communications. Additionally, the spacecraft have 10s of watts of power available for transmitting signals, which is a fair bit considering (while on the other end the ground stations have up to hundreds of thousands of watts to transmit). The ground-stations in the deep space network (DSN) are tens of meters across, a small antenna is 34m, the biggest ones are 70m across. That also provides a huge amount of gain alone. It means that there is more area to collect signals from the spacecraft and it means that the beam from the ground station to the spacecraft is much tighter, concentrating the total transmission power into a smaller cross-sectional area at the distance of the spacecraft.
The spacecraft also uses error correcting codes, which involve transmitting many more bits than the underlying data, but in such a way that errors due to noise are not only detectable but correctable.
On top of all of that you have the state of the art low noise amplifiers in the DSN antennae. A typical low noise amplifier is a carefully built electronics assembly made by experts. The DSN amplifiers? They use 99.95% purity ruby rods chilled to 4 degrees above absolute zero to form microwave MASER based amplifiers.
It's published by the JPL as part of the "Deep Space Communictions and Navigation Series". The rest of the books in the series, listed in the book's front matter, have some fascinating titles.
Cool video, thanks! They also mention this website[1] where you can see the status of the whole DSN live, what antennas in what locations are communicating with what spacecraft, with signal strengths and transmit powers and bitrates and all.
They mentioned that the received signal from the Voyager spacecraft is actually stronger than the signals from several closer craft, because the Voyagers have such good antennas.
The videos of their decoder screen brings back memories of doing very similar things with oilfield tools. The same sorts of techniques are used to get data from deep below the earth, though not with RF but mud pulse telemetry instead. Same digital encoding types and decoders. I got to work with the guys who designed all of the telemetry systems and wrote the decoders for that stuff too.
It's obviously a question of power and antenna gains, but a very important role is played by the encoding: Pioneer before, and Voyager after introduced concatenated codes [0], which consist of a viterbi decoded convolutional code inside an outer Reed Solomon code.
Curiously, those codes are now superseded by other, more modern approaches, for example Turbo Codes [1] which are used not only in deep space probes, but also in cellular communications and other applications that we consider normal these days.
I worked as an RF engineer for a few years and one of the senior engineers once told me a story about how they launched Voyager (I think it was Voyager) with a Viterbi encoder, even though we didn't have the ability to make a decoder at that time due to lacking the computing power. So they launched it knowing they would eventually have the technology, and of course they were right. No idea if that's true or not but I love the story.
According to the inverse-square law, doubling the distance will reduce the power of the signal by 1/4th. The moon is about one light second away, whereas Voyager is about 70,000 light seconds away. If we round down to 64k light seconds, that's about 16 doublings. If each doubling represends a 6db loss, that's about 96 decibels.
So, starting from a system that can communicate from Earth to the moon, if you can find a way to add 64 decibels then it can work from Earth to Voyager. Ways to add decibels include using more directional antennas on one or both ends or transmitting with more power. Alternatively, you can make up some of those decibels by communicating much slower.
The interesting thing about the inverse square law is that it's insensitive to the scales involved. For instance, going from 10 meters to 20 meters results in a 6db loss, and going from 1 light year to 2 light years also results in a 6db loss. This is much different from, say, light in a fiber optic cable, which would experience a 6db loss from impurities in the glass each time the light traveled some constant distance.
That's assuming you're firing the signal out in all directions though, right? For example, a laser doesn't drop in power in this way. I would think a tightly focused radio signal could also avoid such extreme degradation.
It's really hard to make electromagnetic radiation perfectly parallel. If you shine a laser pointer at something far away, the dot gets bigger with distance.
If you could send a perfectly parallel beam, it would effectively be an antenna with infinite gain. As far as I know, that's not possible but getting as close as you can is a good strategy. There's also antenna aiming limitations to consider -- it's possible to have too much gain if it exceeds your ability to point in the right direction.
The opposite extreme is an isotropic radiator, which emits equally in all directions. (That isn't possible either, but it's a good theoretical baseline.) Antenna gain is usually described relative to an isotropic radiator. So, an antenna with a gain of 12dbi means that in the direction it sends its strongest beam, it's 12 decibels stronger than it would be if the antenna were an isotropic radiator.
I think that's the crucial point. While transmission through a cable etc. has exponential decay, transmission through vacuum has quadratic decay, so much more feasible.
I'm not sure that the more interesting bit is the voyager->earth part.
Keep in mind that there are inefficiencies in simply transmitting with more power. The more you amplify, the more noise you introduce. No matter what you do, you can never improve the size and hardware that you're transmitting to.
I don't work much with RF, but, with optical transmissions, the major innovations I've seen are from better receivers that are better able to separate signal from noise at lower power levels. On the earth side of things, we can use massive dishes connected to modern hardware that have very advanced signal processing capabilities. Ultimately, Voyager is 1960s-era hardware with very very very minimal ability to change the software in any way.
If they wanted to (and had the funding to) build a dish on earth that was 10x larger to receive the signals from Voyager with hugely advanced signal processing, that's a totally doable thing. On the other hand, there is virtually nothing you can do to make voyager hear better.
Ultimately, its a lot easier to amplify something faint than it is to shout louder.
> Ultimately, its a lot easier to amplify something faint than it is to shout louder.
Yes, but since you are amplifying the noise right along with the signal if the other side shouts louder it really helps. As does a very good directional antenna (parabolic, very solid mount, very precise control of its orientation).
It’s mostly just very high gain antennas in both directions. You don’t need all that much power if your data rate is very slow and you have a very narrow beam.
(Searched for "voyager communication" on DDG, top hit.)
I was surprised to learn that it's a ground-based system. I'd think they would need antennas in space (on satellites) so that you can both send extremely powerful signals without disturbing others, and receive without having to go through the atmosphere. Instead, there are just three ground stations at approximately 120° around the earth for continuous communication.
Remarkable. I'm vividly reminded of that scene in the movie, Apollo 13, where this is said: [Gene Kranz:] I want you guys to find every engineer who designed every switch, every circuit, every transistor and every light bulb that's up there. Then I want you to talk to the guy in the assembly line who actually built the thing. Find out how to squeeze every amp out of both of these goddamn machines.
NASA has a remarkble group of engineers who know how to get every last erg of energy out of that machine.
I think Apollo 13 did a lot to show what talented engineering teams can do. They also didn't shy away from real terminology and rarely stopped to explain it. No other movie has done that in my experience.
Very impressive. Every day still the envelope of what mankind has touched is still expanding because of this craft. It's a tiny mark on a vast universe but for some unspecified reason it makes me feel very happy to know that it is out there and still ticking, I am not looking forward to the day that it eventually will shut down but even as an inert man-made mass that far out it will be an amazing accomplishment.
I am not looking forward to the day when it somehow returns, starts blowing up star ships, ultimately taking over one of them, and tries to seduce the crew
That... that was really something. That was and is incredibly engaging for me, though it's quite different and I'd understand if someone didn't find it to their taste. What a totally beautiful artifact of the internet.
That's actually a great movie plot, not sure if it has been done before.
Not with Voyager, but for example:
The year is 2243; a spacecraft that humans sent out of the solar system on a one way trip launched in 2045, has once again come into contact unexpectedly and is re-entering our solar system. The system seems to have been updated and is sending information that would have not existed when it was launched and is potentially foreign tech in 2243.
This ship was never supposed to come back...
Edit: Ok, I have admittedly not seen the first Star Trek movie.. I probably should =p
Rather belatedly the human race realizes - after decoding some interstellar video - that the Voyager's trajectory will bring it sooner or later into contact with a race whose sole mission is to eradicate all other intelligent life.
The Voyager's creators helpfully adding a map indicating its origins prompt the recall of the century: launch a mission to overtake both Voyagers and to capture them and bring them back before they are discovered.
Upvoted purely because I love the fact that there's someone here who hasn't seen ST:TMP.
(And you needn't bother, honestly. It's the franchise's answer to 2001, put together by people who didn't really get what made 2001 great. If, like me, you can't get enough absurdly prolonged sequences of old-school practical model effects in effectively static poses, then you'll love it to pieces, but otherwise...)
You just described the plot of the first Star Trek film. Even better, it was a Voyager probe (a fictional Voyager 6) that was augmented by alien machine intelligence and returned to Earth.
That's fanon. Yeah, I sort of like the idea too, and yeah, Goldsmith to some extent may have styled the First Contact Borg leitmotif after V'ger's from TMP, and yeah, maybe he did that deliberately, and yeah, somebody's friend of a friend said that Gene Roddenberry once coughed in a way that could be interpreted as suggesting he'd had in mind the Borg creating V'ger all along - but it's fanon all the same.
(Me, I like Ron Jones's theme from The Best of Both Worlds a lot better, anyway...)
I have a vague recollection of the humanoid that V'ger hijacked to serve as a voice being romantically involved with the original captain that Kirk replaced, and that relationship being exploited and becoming a plot element later. So I think there was some going on...
Back in the early 90's I wondered why so many Unix boxes had 'vger' in their name. Not until this year, when I watched the original Star Trek with my youngest, did I realize what it was all about.
Sad thing is I saw the movie in the theater when it was first released...just didn't put the two together.
The first two Linux machines I ever had to admin back in the 90's where called Picard and Kirk (Picard was the primary, Kirk the secondary (no guessing which series I preferred)).
The round-trip request/response time for a command is 39 hours (!) ... I guess the team has normalized to that latency, but when asking a system to fire with paths of execution plus hardware plus propellant/etc that haven't been used for 37 years ... I can only imagine the tension and celebration.
Related question ... can an easily amateur listen to response transmissions like this that come back from probes?
I had a chance to visit the Deep Space Network facility at Goldstone several years ago (definitely worth a visit if you can arrange one). The antennas they use vary in size from 26 to 70 meters in diameter, and even then they need to use lots of process gain because the signal is still several dB below the noise floor. Amateur tracking would probably be incredibly difficult.
Googling Amateur-DSN will probably give you a link to the Yahoo group where the people who do that kind of thing hang out. The short answer is that yes, numerous interplanetary probes can be received by amateurs with moderate effort/expenditure, but reception from the Voyagers is out of the question without access to a massive antenna.
In the spirit of what this community's name suggests it's about, how hard would it be for someone to hack into the spacecraft by sending it a signal to turn on its thruster too soon given the technology is 40 years old?
Has anything like this been tried before with other spacecrafts?
"how hard would it be for someone to hack into the spacecraft by sending it a signal"
You'd need to totally own the DSN. According to the Wiki:
Because of the enormous distances and the resultant weak signals from the spacecraft, the large antennas and the very sensitive receivers of the DSN are required to provide the necessary communications capabilities. The DSN is the world's largest and most sensitive spacecraft communications network. It consists of three deep space communications complexes located approximately 120 degrees of longitude apart around the world: at Goldstone, California; near Madrid, Spain; and near Canberra, Australia. This placement permits continuous communication with a spacecraft.
> In the spirit of what this community's name suggests it's about, how hard would it be for someone to hack into the spacecraft by sending it a signal to turn on its thruster too soon given the technology is 40 years old?
Perhaps listening to the traffic could help deciphering the encryption (if any).
What it wouldn't be easy at all is to have antennae large enough and in various parts of the world: amateurs still don't have the capacity to do that.
> Has anything like this been tried before with other spacecrafts?
“The best known of alleged takeovers of satellite control occurred in 2007 and 2008. In particular, a serious attack was observed in 2008 when hackers obtained the control of the NASA Terra EOS earth observation system satellite for 2 minutes in June and for another 9 minutes in October. Fortunately the attackers didn’t damage the satellite during the time they gained control of it.”
You are correct this wasn't the article I was looking for, didn't read it to verify. I can't find it now but 1-2 years ago some people used that dish to reactivate a "lost" satellite that had not been used for several years.
There were absolutely compromises, and the engineers who shipped it knew myriad ways in which it could be better.
To answer the question:
Find something you think is equally cool, learn what you can about the field, be open to the possibility of a pay cut, and start knocking on doors. Sometimes doors open. Work really hard when they do.
Two months before the Voyager probes were shipped for launch it was found out that Jupiter's magnetic fields and radiation environment were a lot stronger than anticipated, in excess of what the spacecraft were designed to tolerate. They ended up wrapping many of the cables on the spacecraft with aluminum foil bought from a local supermarket as a protective measure.
Does it need to be a job? If not, you can build your own low orbit satellites, scale rockets, satellites communications, aquatic robotics and more. In fact, aquatic robotics are one of the most approachable ones because you can do it in a nearby lake/river/beach and do proper science. Plus you can team up with local scientists and help them gather/process data.
Even building a cube-sat that never leaves your desk would be an interesting hobby project, really. Non-experts would certainly learn a ton from doing so, and you'd end up with a cool conversation piece, if nothing else.
You don't say what kind of engineering you do, but you could do worse than working at a particle physics lab.
You have everything from data analysis, complex control systems, physics simulations, high voltage electrical engineering... the list goes on.
Ok, the pay isn't silicon valley level but most labs take work life balance and professional development quite seriously and you get to work on cool stuff.
I just want to say that I've literally done this and it was awesome. Granted it was when I was at university and it was a "part time" job, but I've often thought about going back. Now this is going back 30 years and academia in NA has probably changed a lot, but at least at that time most of the top research groups had enough money to hire full time "technicians". At my university it was a union position, so the pay and benefits were not bad compared to the rest of society. Of course compared to the high tech industry, the pay was not even close :-) Probably for that reason, every body I worked with was passionate, brilliant and more than a bit quirky. Anyway, I ended up working in a chemistry group doing crystallography, a physics group doing high energy physics and an astronomy group that was working on community education programs. Each team had really interesting challenges.
One thing I would caution (from my experience) is that the attitude was very much "get it to work" vs "do it properly". I was writing software and had quite a bit of freedom, but the hardware guys were often tasked with, "We have this problem and there is nothing that we can buy/afford that will solve it. Could you please invent something? You have that mountain of spare parts from previous projects to work with". They would be wandering around the department saying things like, "Do you need that <whatever piece of electronics> any more?", and then would steadfastly break it down to get the parts/components that they needed. Probably less reusable stuff in electronics these days, but I remember being pretty awestruck at the time by what they could scavenge and then build.
I remember in the physics lab, my supervisor/boss had bought a laser printer from Europe. Because it was 240 volt, they built a voltage doubler so that they could use it. One day they accidentally plugged it into 2 voltage doublers and... well, predictably it no longer worked. But my buddy quite happily pounced on the dead carcass and I don't think it lasted more than a couple of hours before the working parts were repurposed for something else.
Like I said, this was a long time ago, but I imagine things still mostly work the same. Awesome place to work.
I currently work for a UK based particle physics facility and a lot of what you say is still true, it is an awesome place to work.
The tension between "get it to work" and "do it properly" is still there, particularly when there is pressure for results for conference papers. We try to do things properly though, simply due to the more onerous safety regulations now.
It is interesting coming across various historical bodges that lurk in dark corners, sort of little engineering time capsules.
aerospace (airliners, hardened electronics for space, etc) / robotics (all those problems with the fukushima robots, precision medical and industrial bots) / medical devices of all kinds
Of course, you can work on whatever you want to whatever standard you want if you do it on your own time & dime, if you have the willpower and the budget, or can find a patron, crowdfunding is viable now.
When you're far enough from the sun to avoid thermal cycles, in the vacuum of space, what forces will cause things to deteriorate? If I wanted something to last forever, deep space would be the perfect place for it.
-- It is a tough radiation environment. Materials are embrittled and altered over time.
-- Many materials age on their own; plasticizers outgas from plastics. You're probably familiar with how once-pliable but now old/aged plastics, even kept sealed in a box, can become crunchy and brittle.
-- Chemistry doesn't stop in space. The thrusters are likely to involve chemically-reactive materials. Any little bit of corrosion, stress-corrosion cracking, etcetera could cause anomalous performance.
Interesting, I didn’t realize cold welding was a problem in space. I assume it can be solved by applying a coating to surfaces that might come in contact with each other.
It definitely gets higher when you leave Low Earth Orbit, because you're leaving the Earth's magnetic field; so the ISS is definitely at the low end of the scale of Voyager's exposure.
Not sure how it varies as you leave the solar system - depends on the exact balance between Solar Energetic Particles (particle radiation from the sun) and Cosmic Rays (particle radiation from outside the solar system), and on how much the cosmic radiation increases as Voyager leaves the heliosphere.
I believe the thing that will kill voyager is primarily the radioactive decay of it's battery. It's power budget is so low now that it's got most everything off almost all the time. Sadly there is a point where they won't be able to turn on the radio to listen.
How does Voyager know where Earth is, such that it can position the dish correctly? Does it use inertia to keep track?
Also, at such an enormous distance, I’d expect very minor dish positioning errors to result in the loss of the line. It’s awesome that they had the skills to build something like that in the 80s.
It doesn't need to point its dish at Earth, it can simply aim for the Sun. It is so far away they are as good as in the same position relative to itself. And the Sun conveniently lights up making aiming a lot easier.
Looking up the math on that, the high gain antenna is within 3dB of max at up to .3 degrees off-target. It's 132 AU out, so Earth is within .41 degrees of the sun. Good enough!
Did they have digital light detectors in the 70s? I mean, it’s trivial now to aim something at the sun now, but they didn’t have image recognition then. A primitive heat sensor perhaps?
Even more impressive, Voyageur 1 was launched in September of 1977 [1]. It was originally built on early 1970's technology. An incredible amount of foresight and luck.
Voyager's antenna is aimed at the sun (because at its distance, earth and sun have close angular separation). So this means the command signal has to overcome microwave noise from the sun.
So this is the same problem as SETI. I know for SETI they reduce stellar noise by assuming that aliens are transmitting in very narrow bandwidths.
Would it be possible to use these thrusters, or even the main thruster, to speed Voyager or slingshot it around something right before it loses power to communicate back to us?
It'd be cool if right before we lose contact of it for good, we got it to go as fast as possible so that it will reach who knows where someday... just slightly faster.
As ssijak pointed out, there's nothing to slingshot around.
The additional speed we might get out of it is tiny compared to the 17km/s it already has.
If they used what little fuel was left to go faster, then wouldn't be able to communicate with the Earth. The current goal is to get information about what's at the edge of the solar system.
We know it's not going anywhere close to anything, any time soon. Wikipedia says "in about 40,000 years, it will pass within 1.6 light-years of the star Gliese 445".
And for all we know, if it goes faster it might pass by some destination it would reach now.
It's in interstellar space. Barring a really lucky encounter with another interstellar body, it'll be another 40,000 years before it's close to anything.
It doesn't seem like it's all the time. Pluto is the largest, Eris is close. Haumea, (225088) 2007 OR10 and Makemake are the only others at least 1/2 the diameter of Pluto.
We are finding more trans-Neptunian objects. There's about 2,500 of them. But as Adams said, "Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is."
Voyager can only be angled a smidgen from it's current path. There's nothing it can reach to do a slingshot.
If Voyager could change its path by 0.1 degree (which it can't), and if all of the trans-Neptunian objects were equally distributed around the Sun (which they aren't - and Voyager is going out of the plane of the ecliptic), then that's still only a 0.2% chance of having something in its path.
just as a scale, this distance is not even a light-day away ! i am just amazed that we can still "hear" it.
anyone have more info on the power with which the signal arrives here at earth ? and how do they make sure that ambient/thermal noise does corrupt it ? thank you !
There's a wealth of fascinating information including book series on deep space communication at the JPL DESCANSO
Deep Space Communications and
Navigation Center of Excellence:
Well, cough, if rocketry is involved then reaction mass is being expended somewhere somehow... whatever the underlying chemistry may be... so it is a finite resource that is subject to depletion...
I think you're saying 'the fuel hasn't been used up' to mean that 'the fuel has not been entirely spent and there is plenty left', and the other person thinks you mean 'no fuel is used at all when the thrusters are fired' which is why they're correcting you. Both are reasonable but different interpretations of 'used up'.
I'm an applied mathematician and a practicing economist, I'm afraid I wouldn't understand chemical reactions as being of one sort or another if they hit me on the head and set me on fire. I'm honest, I know my limits, and chemical ignorance is one of them.
They are pressure fed hydrazine monopropellant thrusters. They are incredibly reliable. Keep in mind that Voyager 1 doesn't have reaction wheels or any other method for controlling its attitude other than its thrusters, and it's 3-axis stabilized. The original thruster set fired thousands of times over a nearly 4 decade period and now the backup thruster set is being rotated into use.
How could a rocket system, which when in operation vents reaction mass into the vacuum of space, ever qualify as a “sealed system”? Surely only the storage tanks could ever qualify as being a “sealed system”, and even then an imperfect one, because there must be one or more potentially leaky valves leading to the actual nozzle somehow?
I always thought "thrusters" were devices that always spewed out majestic flames and plumes of smoke whenever they are fired. I was surprised, as a kid, to learn that the Voyager thrusters effectively are no more exciting that pressing the nozzle of an aerosol spray can for a split second. Stands to reason that they don't need much force to affect the spacecraft inertia at those weights and speeds.
Still, a stupendous achievement to have them still working 40 years after being deep frozen in space!
If you read the specs (http://www.astronautix.com/m/mr-103.html) of the thrusters in question, you can see that they do "spew flames" and there is a combustion chamber:
Irrespective of what is used, consider that in the vacuum of space, when you're not in a hurry, you'd only need the tiniest bit of propellant/thrust for an attitude correction. Even for a comparatively heavy vehicle like voyager. The other forces at play are so miniscule, that you only need a ridiculously small force to start it rotating (and the opposite when you want it to stop).
I'm too old now: but I so wish I could have been a young engineer on such a project. The title is literally "37 years later." (And that's not from launch.)
> This week, the scientists and engineers on the Voyager team did something very special.
I would say if you still manage to run sophisticated system that is 37 years old, even more challenging when its out in space, everything you do is special.
Every single aspect of space travel is an engineering/mathematic/scientific marvel. Not only did we plan, build, launch these, (before I was born) but we're still communicating (until we can't).
I'm reading links people have posted here, trying to understand how we communicate with these probes. It's fascinating.