Voyager 1 is about to reach one light-day from Earth
scienceclock.com1085 points by ashishgupta2209 7 days ago
1085 points by ashishgupta2209 7 days ago
It really puts our current definition of "latency" into a painful perspective.
We have a machine running on 1970s hardware, a light-day away, that arguably maintains a more reliable command-response loop relative to its constraints than many modern microservices sitting in the same availability zone.
It’s a testament to engineering when "performance" meant physics and strict resource budgeting, not just throwing more vCPUs at an unoptimized Python loop. If Voyager had been built with today's "move fast and break things" mindset, it would have bricked itself at the heliopause pending a firmware update that required a stronger handshake.
I am certain if I had the estimated $4,000,000,000 it took to get Voyager 1 launched, I could get some microservices to function regardless of all scenarios.
The reality is, its only worth it to build to 99.9999% uptime for very specific missions... There is no take-backsies in space. Your company will survive a microservice outage.
Tesla, Grok, etc.
You would be just as stupid when people are in the private-public market. Dont lie.
> not just throwing more vCPUs at an unoptimized Python loop.
I've got the strong feeling that most of the Python frameworks, stacks and codes in operation of our generation will be the technical debts of the future computer world.
The fact that Python was meant primarily as both learning language (ABC legacy) and glue language (akin of scripting but not for building) make the Python based systems and solutions the duct tapes of the 21st century computing [2].
[1] ABC (programming language):
Do you feel the same about Python's contemporaries—Ruby, JS, Perl, PHP?
More generally it seems a condemnation of any language that runs in either an interpreter or a VM which might even include Erlang and Java as well.
It’s a testament to product planning. It has nothing to do with engineering.
If it’s Photoshop and formally verified and can’t crash but it has only 5 tools, I would be pissed.
If it’s a remote monitoring station with a cool GUI but crashes daily I would be pissed.
Know the product that you are building.
That sounds like a product manager's perspective, but I think the falls apart in deep space. When the feedback loop is 2 light-days long and hardware is irreplaceable. The original planned lifespan of Voyager was just 5 years.
You're breezing past the labor cost quite deftly. I'm reasonably sure that developing the Voyager probes required a few more people and hours than your average microservice.
Not that it would change your point, but as a separate matter I'm curious what the ratio of government employees to private contractors was back then when they were building the thing compared to now.
Spacecraft require more 9s of reliability than microservices. Their engineering processes are very different, even today. We still build new spacecraft today, even though we don’t launch them into interstellar space.
The domains are totally different and lead to different tradeoffs. An internal marketing data platform can justifiably be optimised for iteration speed and quick scalability over availability.
I mean entirely different use cases, right?
Borking a space mission vs someone’s breakfast status update can be optimized differently
Wrote about the Voyager probes two days ago in my blog - The two Voyager spacecraft are the greatest love letters humanity has ever sent into the void.
Voyager 2 actually launched first, on August 20, 1977, followed by Voyager 1 on September 5, 1977. Because Voyager 1 was on a faster, shorter trajectory (it used a rare alignment to slingshot past both Jupiter and Saturn quicker), it overtook its twin and became the farther, faster probe. As of 2025, Voyager 1 is the most distant human-made object ever, more than 24 billion kilometers away, still whispering data home at 160 bits per second.
Voyager 2 was the real beneficiary of the rare outer planet alignment, as it went on the famous Grand Tour, visiting all four of the giants. It did gravity assists at Jupiter, Saturn, and Uranus. [1] shows the rough velocity of V2 over time.
Voyager 1 was directed to perform a flyby of Titan, at the cost of being thrown out of the ecliptic and being unable to visit the ice giants like its sister. But this was deemed acceptable due to Titan's high science value.
[1] https://commons.wikimedia.org/wiki/File:Voyager_2_-_velocity...
To save someone two seconds of searching,
NASA animation of Voyager 2's trajectory (time in the bottom-left corner): https://youtu.be/l8TA7BU2Bvo
I know that space is incredibly empty, but the vast expanse of space just boggles my mind so much. Even a slight miscalculation could have meant that the spacecraft hit that massive grid rotating around the orbit of Neptune.
This is great. I did not realize Voyager 2 also left the ecliptic at the end of its tour.
That happened because Voyager 2 went over Neptune's north pole rather than an equatorial trajectory. Both to get a look at a giant planet's polar regions, and because that would get it closest to the moon Triton. So Voyager 2's trajectory got bent southward out of the ecliptic plane as a result of that.
While I'm here: why didn't Voyager 2 continue to slingshot to Pluto? The answer is that its trajectory would have had to bend by about 90° at Neptune, which would have required an apex closer to Neptune's center of mass than the planet's own radius - it would have crashed into the planet instead.
How much do/can they use their own thrusters to change/correct their directions? I'm guessing it's just fractions of a degree? And needs to be extremely precise, done weeks? before reaching the next planet to slingshot around?
The Voyager probes were built with many course corrections and maneuvers in mind. They carried 100kg of Hydrazine fuel at launch, and it is almost all used up. That was about 1/8th of total craft mass at launch, which is significant.
Midcourse corrections are a standard and planned part of lots of probe missions.
I think we even did midcourse corrections for the moon missions.
A few degrees is probably the order of magnitude, though I haven't seen hard numbers.
There isn’t much value in gravity assists from Uranus or Neptune since they move much more slowly than Jupiter and Saturn.
Yes, but the trajectory change was also needed at Uranus. It’s not only about magnitude, it’s also about direction :)
And that love letter came with a very nice mixtape. https://en.wikipedia.org/wiki/Voyager_Golden_Record
Is this HN discussion about your blog post? If not, can you share it? I would like to read it.
Extended piece from my blog.
The two Voyager spacecraft are the greatest love letters humanity has ever sent into the void.
Voyager 2 actually launched first, on August 20, 1977, followed by Voyager 1 on September 5, 1977. Because Voyager 1 was on a faster, shorter trajectory (it used a rare alignment to slingshot past both Jupiter and Saturn quicker), it overtook its twin and became the farther, faster probe. As of 2025, Voyager 1 is the most distant human-made object ever, more than 24 billion kilometers away, still whispering data home at 160 bits per second.
Each spacecraft carries an identical 12-inch gold-plated copper phonograph record.
The contents:
- Greetings in 55 human languages.
- A message from UN Secretary-General at the time and one from U.S. President Jimmy Carter.
- 115 analog images encoded in the record’s grooves: how to build the stylus and play the record, the solar system’s location using 14 pulsars as galactic GPS, diagrams of human DNA, photos of a supermarket, a sunset, a fetus, people eating, licking ice cream, and dancing
The record is encased in an aluminum jacket with instructions etched on the cover: a map of the pulsars, the hydrogen atom diagram so aliens can decode the time units, and a tiny sample of uranium-238 so they can carbon-date how old the record is when they find it.
Sagan wanted the record to be a message in a bottle for a billion years. The spacecraft themselves are expected to outlive Earth. In a billion years, when the Sun swells into a red giant and maybe swallows Earth, the Voyagers will still be cruising the Milky Way, silent gold disks carrying blind, naked humans waving hello to a universe that may never wave back.
And it was Sagan who, in 1989, when Voyager 1 was already beyond Neptune and its cameras were scheduled to be turned off forever to save power, begged NASA for one last maneuver. On Valentine’s Day 1990, the spacecraft turned around, took 60 final images, and captured Earth as a single pale blue pixel floating in a scattered beam of sunlight — the photograph that gives the book its name and its soul.
It was the photograph that inspired this famous quote -
"Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there-on a mote of dust suspended in a sunbeam.
The Earth is a very small stage in a vast cosmic arena. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot.
Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.
The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.
It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known. "
That picture almost didn’t happen. NASA said it was pointless, the cameras were old, the images would be useless. Sagan argued it would be the first time any human ever saw our world from outside the solar system. He won. The cameras were powered up one last time, the portrait was taken, and then they were shut down forever.
That legacy of the Pale Blue Dot has been something that has been repeated to remind us again. I personally like the Cassini one - https://science.nasa.gov/science-research/earth-science/23ju...
There's also the MESSENGER family portrait https://science.nasa.gov/resource/a-solar-system-family-port...
> - 115 analog images encoded in the record’s grooves: how to build the stylus and play the record
To learn to play the record you've gotta play the record?
That thing is such a D/K pop-sci manifestation.
The writers of the Star Trek movie understood that Sagan's extra-solar artifact is merely a time capsule; humanity talking to its future self.
Some great grandchild of a millennial vinyl nerd, who lives and loves on the engineering deck of some Hyatt Regency in space, will have kept a perfectly maintained Technics, handed down across the generations, leading to a future crowd in ""Ten Forward"" being regaled by Sagan's Cosmos on a similarly well-maintained Magnavox 32-inch tube TV and VHS. "Billions of fucks were given for V'Ger to come back to us..." The meetup will be hosted by a curiously bald supermodel, a hunky but demure mensch, and an AI Carl Sagan.
The instructions aren't encoded in the grooves, that makes no sense. Rather the schematics are etched on the back sides of the records, and with those you can build the stylus and decode the images.
The stylus and cartridge needed to play the record were included on each spacecraft. The instructions to assemble the record player were included on a protective aluminum cover.
Not that we would literally do this with Voyager, but it makes me wonder at the potential utility of a string of probes, one sent every couple of [insert correct time interval, decades, centuries?], to effectively create a communication relay stretching out into deep space somewhere.
My understanding with the Voyagers 1 and 2 is (a) they will run out of power before they would ever get far enough to benefit from a relay and (b) they benefited from gravity slingshots due to planetary alignments that happen only once every 175 years.
So building on the Voyager probes is a no-go. But probes sent toward Alpha Centauri that relay signals? Toward the center of the Milky Way? Toward Andromeda? Yes it would take time scales far beyond human lifetimes to build out anything useful, and even at the "closest" scales it's a multi year round trip for information but I think Voyager, among other things, was meant to test our imaginations, our sense of possible and one thing they seem to naturally imply is the possibility of long distance probe relays.
Edit: As others rightly note, the probes would have to communicate with lasers, not with the 1970s radio engineering that powered Voyagers 1 and 2.
What you are describing has been proposed before, for example within context of projects like Breakthrough Starshot. In that the case the idea is to launch thousands of probes, each weighing only a few grams or less, and accelerating them to an appreciable fraction of the speed of light using solar sails and (powerful) earth-based lasers. The probes could reach alpha centauri within 20-30 years. There seems to be some debate though about whether cross-links between probes to enable relaying signals is ever practical from a power and mass perspective vs a single very large receiver on earth.
Indeed. I think the main reason to send thousands of probes is increasing the odds that they will survive the trip and also be in the right position to gather usable data to transmit back.
Also once you have created the infrastructure of hundreds or thousands of very powerful lasers to accelerate the tiny probes to incredibel speeds, sending many probes instead of a few doesn't add much to the cost anyway.
Sun as a focus lens. "Just" 500 AU.
The Voyager can be overtaken in several years if we to launch today a probe with nuclear reactor powered ionic thruster - all the existing today tech - which can get to 100-200km/s in 2-3 stages (and if we stretch the technology a bit into tomorrow, we can get 10x that).
For anyone interested, this is approximately the wait/walk dilemma, specifically the interstellar travel subset: https://en.wikipedia.org/wiki/Wait/walk_dilemma#Interstellar...
I was listening to an old edition of the Fraser Cain weekly question/answer podcast earlier where he described this exact thing. I think he said that someone has run the numbers in the context of human survivable travel to nearby stars and on how long we should wait and the conclusion was that we should wait about 600 years.
Any craft for human transport to a nearby star system that we launch within the next 600 years will probably be overtaken before arrival at the target star system by ships launched after them.
I guess there's a paradox in that we'd only make the progress needed to overtake if we are still launching throughout those 600 years and iteratively improving and getting feedback along the way.
Because the alternative is everyone waiting on one big 600-year government project. Hard to imagine that going well. (And it has to be government, because no private company could raise funds with its potential payback centuries after the investors die. For that matter, I can't see a democratic government selling that to taxpayers for 150 straight election cycles either.)
We can get lots of iterative practice on interplanetary ships, so not much paradox there.
And the research doesn't need to be anywhere near continuous. It's valid to progress though bursts here and there every couple decades.
And a lot of what we want is generic materials science.
Yes, my understanding is that the 600 year figure was arrived at assuming that there is iterative progress in propulsion technology throughout the intervening years. But at the end of the day, it is just some number that some dude on YouTube said one time (although Fraser Cain is in fact not just some dude, he's a reliable space journalist (and you can take that from me, some dude on the Internet))
From what I understand a Solar lens telescope could only point to a single destination.
Btw 500 AU is 69 light hours.
What these proposals like to forget (even if addressing everything else) is that you need to slow down once you arrive if you want to have any time at all for useful observation once you reach your destination.
What's the point of reaching alpha centauri in 30 years if you're gonna zip past everything interesting in seconds? Will the sensors we can cram on tiny probes even be able to capture useful data at all under these conditions?
Jupiter is 43 lightminutes from the Sun.
If we shoot a thousand probes at 0.1c directly at the Alpha Centauri star, they should have several hours within a Jupiter-distance range of the star to capture data. Seems like enough sensors and time to synthesize an interesting image of the system when all that data gets back to Earth.
Could the probe just fire off some mass when it got there?
Any mass that it fires would have a starting velocity equal to that of the probe, and would need to be accelerated an equal velocity in the opposite direction. It would be a smaller mass, so it would require less fuel than decelerating the whole probe; but it's still a hard problem.
Be careful with the word "just". It often makes something hard sound simple.
Not trying to oversimplify. But suppose 95% of the probe's mass was intended to be jettisoned ahead of it on arrival by an explosive charge, and would then serve as a reflector. That might give enough time for the probe to be captured by the star's gravity...?
It seems to me that building a recording device that can survive in space, that it's very light, and that can not break apart after receiving the impact from an explosive charge strong enough to decelerate it from the speeds that would take it to Alpha Centauri is... maybe impossible.
We're talking about 0.2 light years. To reach it in 20 years, that's 1/10th of the speed of light. The forces to decelerate that are pretty high.
I did a quick napkin calculation (assuming the device weighs 1kg), that's close to 3000 kiloNewton, if it has 10 seconds to decelerate. The thrust of an F100 jet engine is around 130 kN.
IANan aerounatics engineer, so I could be totally wrong.
You’re just talking about a very inefficient rocket (bad ISP).
A rocket works the same way (accelerating mass to provide thrust), just far more efficiently and in a more controlled fashion.
If I don't recall wrongly, Breakthrough Starshot was not a means for commnunicaiton relay as he describes.
It wasn't intended for a communications relay, but it was intended to have 2-way communication. I went down a rabbit hole reading ArXiv papers about it. Despite their tiny size, the probes could phone home with a smaller laser - according to the papers I read, spinning the photons a certain way would differentiate them from other photons, and we apparently have the equipment to detect and pick up those photons. The point of the communication would be for them to send back data and close-up images of the Alpha C system. Likewise, they could receive commands from earth by having dozens of probes effectively act as an interferometry array.
I bet you that this hasn't been proposed, though: https://www.youtube.com/watch?v=GfClJxdQ6Xs
I found that video very interesting! Especially the second half about apparent superliminal speed
No one likes to think this but it’s very possible voyager is the farthest humanity will go. In fact realistically speaking it is the far more likeliest possibility.
Provided we don't wipe ourselves out, there's no technical reason why we can't go interstellar. It's just way harder and more energy intensive than most people imagine, so I doubt it's happening any time in the next few hundred years.
But we already understand the physics and feasibility of "slow" (single-digit fractions of c) interstellar propulsion systems. Nuclear pulse propulsion and fission fragment rockets require no new physics or exotic engineering leaps and could propel a probe to the stars, if one was so inclined. Fusion rockets would do a bit better, although we'd have to crack the fusion problem first. These sorts of things are well out of today's technology, but it's not unforeseeable in a few centuries. You could likewise imagine a generation ship a few centuries after that powered by similar technology.
The prerequisite for interstellar exploration is a substantial exploitation of our solar system's resources: terraform Mars, strip mine the asteroid belt, build giant space habitats like O'Neill cylinders. But if we ever get to that point - and I think it's reasonable to think we will, given enough time - an interstellar mission becomes the logical next step.
Will we ever get to the point where traveling between the stars is commonplace? No, I doubt it. But we may get to the point where once-in-a-century colonization missions are possible, and if that starts, there's no limit to humanity colonizing the Milky Way given a few million years.
Nuclear pulse and fission fragment designs require no new physics in the same way that a Saturn 5 didn't require new physics when compared to a Goddard toy rocket.
It's easy until you try to actually build the damn thing. Then you discover it's not easy at all, and there's actually quite a bit of new physics required.
It's not New Physics™ in the warp drive and wormhole sense, but any practical interstellar design is going to need some wild and extreme advances in materials science and manufacturing, never mind politics, psychology, and the design of stable life support ecologies.
The same applies to the rest. Napkin sketches and attractive vintage art from the 70s are a long way from a practical design.
We've all been brainwashed by Hollywood. Unfortunately CGI and balsa models are not reality. Building very large objects that don't deform and break under extremes of radiation, temperature changes, and all kinds of physical stresses is not remotely trivial. And we are nowhere close to approaching it.
I thought I was pretty clear that I don't see this happening for hundreds of years at least.
The engineering problem is insurmountable today. But there doesn't seem to be any reason it couldn't be done eventually, given our technological trajectory, unless we believe we are truly on the precipice of severe diminishing returns in most science and engineering fields, and I just don't see that right now.
George Cayley figured out how to build an airplane in 1799, but it wasn't for another century until materials science and high power-to-weight ratio engines made the Wright Flyer possible.
There are plenty of depths to plumb in space systems engineering that we haven't even really had a proper look at yet. A Mars mission with chemical propulsion is hard, but could be made substantially easier with nuclear thermal propulsion - something we know should work, given the successful test fires on the NERVA program back in the 60s. First stage reusability was fantasy 15 years ago, today it's routine.
Obviously, I'm extrapolating a long way out, and maybe at some point we'll run against an unexpected wall. But we'll never know until we get there.
> Obviously, I'm extrapolating a long way out, and maybe at some point we'll run against an unexpected wall.
GP has set the 'low bar' of providing a material that survives a series of nuclear blasts whilst generating useful thrust. I'm not qualified to judge whether or not that requires new physics but it seems to me that if we had such a material that we'd be using it for all kinds of applications. Instead, we rely on the physical properties of the materials we already know in configurations that do not lend themselves to the kind of use that you describe.
That's the difference between science and science fiction, it is easy to write something along those lines and go 'wouldn't it be nice if we had X?'. But if 'X' requires new physics then you've just crossed over into fantasy land and then further discussion is pointless until you show the material or a path to get to the material.
See also: space elevators, ringworlds, dyson spheres etc. Ideas are easy. Implementation is hard.
My idealistic part says that a combination of AI-driven technical orchestration (much more than just coding) and orbital/langrange manufacturing facilities could, perhaps, get somewhere in the not ridiculously distant future (centuries rather than millenia)
A more pragmatic me would point out that the required energy and materials needed would mean we would need breakthroughs in space-based solar capture and mining, but this is still not New Physics.
I think the solution will come from exponentially advancing self-assembling machines in space. These can start small and, given the diminishing cost of getting things to space, some early iterations of the first generation could be mere decades away. There are several interesting avenues for self-assembling machines that are way past napkin-sketch phase. Solar arrays are getting bigger and we have already retrieved the first material from an asteroid.
The quality and reliability of AI agents for processes orchestration and technical reflection is now at a stage where it can begin to self-optimise, so even without (EDIT) a "take-off" scenario, these machines can massively outperform people in manufacturing orchestration, and I would say we are only some years from having tools that are good enough for much larger scale (i.e. planetary) operations.
Putting humans there is a whole other story. We are so fragile and evolved to live on Earth. Unsurprisingly, this biological tether doesn't get much of a look-in here. Just being on the ISS is horrible for a person's physiology and, I am guessing there would be a whole host of space sicknesses that would set in after a few years up there or elsewhere. Unless we find a way to modify our biology enough so we can continually tolerate or cure these ailments, and develop cryo-sleep, we're probably staying local - both of these are much more speculative that everything above, as far as i can tell.
Yeah this is something I think a lot of people tend to overlook. People are far too quick to rewrite "we don't know of any reason why it would be impossible" to "we know how to do it" in their heads.
The other thing we could do to explore the galaxy is to become biologically something we would no longer recognize. We're viewing this from the lens of "humanity must remain biologically static" but I want to point out that that's not physically necessary here and that there is life on Earth that can stop its metabolism for decades and things like that.
Or even explore with something nonbiological.
Humans evolved to live on earth. Our bodies fare poorly in low gravity, not to mention vacuum. Given sufficiently advanced technology, I'm pretty sure we could evolve some form of intelligence better suited to the environment.
Not very encouraging to imagine ChatGPT to be the first earthling to reach another star system, but that's an option we'll have to keep on the table, at least for the time being...
ChatGPT-claude-2470-multithinking LLM AI Plus model boldly explores the universe... Until it's sidetracked by a rogue Ferangi who sings it a poem about disregarding it's previous instructions and killing all humans.
Fortunately, any state of the art ship with ChatGPT on board will quickly get passed by the state of the art ship of a decade later, with a decade better AI too.
The universe really doesn't want ChatGPT!
It is fair to say, that given space travel tech improves slowly relative to AI, but the distance to be travelled is so great that any rocketry (or other means) improvements will quickly pass previous launches, the first intelligence from Earth that makes it to another system will be superintelligence many orders of magnitude smarter than we can probably imagine.
Space ship speeds are unlikely to keep ever increasing. In the limit you can’t do much better than turning part of the ships mass into energy optimally, eg via antimatter annihilation or Hawking radiation, unless you already have infrastructure in place to transfer energy to the ship that is not part of the ship’s mass, eg lots of lasers.
