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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 correc
by glenstein 11mo ago
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.
- Aperocky 11mo agoNot useful, because the signal are too weak to be picked up probe to probe. On earth, the tiny signal from Voyager at this distance is picked up by dish the size of a football field; same with sending of the signal.
- nntwozz 11mo agoWhat if the probes carry smaller probes left behind at specific intervals that act as repeaters? These baby probes could unfold a larger spiderweb antenna the size of a tennis court.
- jandrese 11mo agoThe problem is each relay needs its own power source so it's not going to be as light and small as you would like. Solar power doesn't work very well outside of the solar system, or even really in the outer solar system. On the plus side your big probe could push off of the small probe to give itself a further boost, also necessary because otherwise the small probes need thrusters to slow themselves to a stop.
- keepamovin 11mo agoWe need quantum entanglement based communication. Maybe without full collapse, using weak measurements, like Alice continuously broadcasts a "retrocausal carrier wave" by sequencing planned future post-selection measurements on her entangled qubits, which backward-propagates through time-symmetric quantum evolution to create detectable perturbations in the present states, biasing Bob's qubits away from pure randomness to encode message patterns. Both parties perform weak measurements on their qubits to extract these subtle signals without collapsing the entanglement, preserving high coherence across the stream. A quantum Maxwell's demon (e.g. many experiments but can be done: https://pubmed.ncbi.nlm.nih.gov/30185956/ https://pubmed.ncbi.nlm.nih.gov/30185956/) then adaptively selects the strongest perturbations from the wave, filters out noise, and feeds them into error correction to reliably decode and amplify the full message.
- wizzwizz4 11mo ago> which backward-propagates through time-symmetric quantum evolution to create detectable perturbations in the present states, That's not how quantum physics works. You might be misunderstanding delayed-choice. If you do think it works this way, I encourage you to show a mathematical model: that'll make it easier to point out the flaw in your reasoning.
- jamiek88 11mo agoYou cannot exchange information with quantum entanglement. It’s impossible.
- keepamovin 11mo agoI put something together: https://github.com/DOSAYGO-STUDIO/quacomms?tab=readme-ov-file https://github.com/DOSAYGO-STUDIO/quacomms?tab=readme-ov-fil...
- mrguyorama 11mo agoThis is nonsense word salad. The paper you link does not demonstrate a Quantum Maxwell's Demon extracting information or energy. >This proposal is speculative and assumes quantum mechanics is incomplete, incorporating elements from Bohmian mechanics (non-local hidden variables) and CSL (stochastic collapses). LMAO, you don't get to change the rules to fit your needs. Come on man. Stop thinking that chatting with LLMs is doing science. You literally just made up fake physics, and claimed that non-existent physics "implies" something.
- foxglacier 11mo agoYou can't leave anything behind. That would need to be accelerated to 50,000 km/h or have even bigger rockets than launched Voyager in the first place.
- boisterousness 11mo agoSure, drop one repeater every light-day. 1500 of them. Each one will need fuel to decelerate enough to remain in place.
- malfist 11mo agoThe dish isn't the size of a football field, it's a 70 meter dish (football field is 110 meters), it can however, transmit at 400 kilowatts of power
- jcims 11mo agoLaser communication could potentially address some of those issues.
- jandrese 11mo agoMaybe, but if your probe is heading directly towards another solar system then it will be backlit by its destination.
- glenstein 11mo agoMy understanding is that's a solved problem - NASA's Deep Space Optical Communication has demonstrated laser communication even with the sun in the background. Laser wavelength and modulation are noticeably different than a stars noise if you filter and just look for the wavelength and modulation of the laser, which is notably shorter and faster than most of the noise coming from the star.
- shagie 11mo agohttps://space.stackexchange.com/questions/33338/why-is-the-operating-temperature-for-the-voyagers-receiver-noise-calculation-ab https://space.stackexchange.com/questions/33338/why-is-the-o... is a neat question that addresses this issue. And yes, the transmitters will need to be powerful enough be a distinct signal over the background of the star that is in the line of sight of the receiver / beyond the transmitter.
- BobbyTables2 11mo agoFootball field might even be too small… Wasn’t Arecibo used for Voyager?
- shagie 11mo agoIt might have from time to time... but it had limited ability to track. As I type this, DNS Now is currently receiving data from Voyager 1. https://eyes.nasa.gov/apps/dsn-now/dsn.html https://eyes.nasa.gov/apps/dsn-now/dsn.html https://imgur.com/a/kXbhRsj https://imgur.com/a/kXbhRsj for a screen shot of the relevant data. The antenna data is https://www.mdscc.nasa.gov/index.php/en/dss-63-2/ https://www.mdscc.nasa.gov/index.php/en/dss-63-2/
- FireBeyond 11mo agoNo. Or not any more, DSS-43 at the Canberra Deep Dish Communication Complex is the only antenna that can communicate with the Voyagers.
- pseudocomposer 11mo agoThis is a silly counterexample - why would we launch them that far apart? It’s a terrible idea for multiple reasons. We’d want them close together, with some redundancy as well, in case of failures. What dish size would be required for a “cylindrical/tubular mesh” of probes, say, 1AU apart (ie Earth-Sun distance)? I’m pretty sure that would be manageable, but open to being wrong. (For reference, Voyager 1 is 169AU from Earth, but I have no idea how dish size vs. signal strength works: https://science.nasa.gov/mission/voyager/where-are-voyager-1-and-voyager-2-now/ https://science.nasa.gov/mission/voyager/where-are-voyager-1...)
- ianburrell 11mo agoLight year is 63,241 AU. That means tens of thousands of relays. It would super expensive and super unreliable. The other problem is that achievable speeds are super slow, Voyager is 25,000 years per light year which means that would wait 100,000 years for relays to Alpha Centauri to be possible. Much easier just to send probe with large antenna or laser, and make a large antenna at Earth.
- thenthenthen 11mo agoStarlink has 10k satellites as per this Month. 60k doesnt seem unreasonable?
- chucksmash 11mo agoStarlink has a use case. At Voyager 1 speeds, it'll take 70,000 years for a probe to reach Proxima Centauri. So you'd just be launching a probe a year for the next 70,000 years to create a temporary chain on a course to fly by one particular star. And for what purpose? Okay, in 70,000 years, if everything works out as expected, we have a chain of probes on a course to fly by Proxima Centauri. What problem does that solve for us ("us" here being whatever is kicking around on Earth after a period of time 5x that of recorded human history thus far).
- glenstein 11mo ago
- rootnod3 11mo agoYou could send a good amount of small probes and make them become the big antenna dish basically. As long as you cover the bases, you can have layers of "big antenna dishes" in onion layers.
- JumpCrisscross 11mo ago> the tiny signal from Voyager at this distance is picked up by dish the size of a football field Lots of small fishes can resemble a large fish.
- glenstein 11mo agoVery true insofar as it's a description of Voyager communications. Voyager was 1970s radio engineering. Radio signals spread wide, so you need a big dish to catch it. These days we are using lasers, and laser divergence is several orders of magnitude smaller. And regardless of tech, relay enforces a minimum distance for any signal to spread.
- boznz 11mo agoUnlike the other comments I actually agree, physics has not changed since the 1970's, even the most focused laser and detector would need to be positioned perfectly to where the next probe would be, and with the nearest star 4 light years away we would be talking a chain of dozens, any of which may fail some way. The probes would also likely be small, cell-phone sized, power restricted, and difficult to shield (you couldn't just throw in the latest wiz-bang 2025 electronics as it all has to be hardened to work multiple decades) Best is a big, transmitter and good receiver one end.
- Fokamul 11mo agoHmm, do you realize, that even if you have 1B probes everywhere. You're still bound by speed of light communication speed, right? It's faster than probe speed in this age, yeah. But still not enough, if we're talking distances to other specific planets, stars, etc. Two possible ways to solve this, humans will become immortal or speed of light bypass method will be discovered.
- serf 11mo agothe post office has utility even if the messages have very high latency. also if this probe network reduces the transmission costs to normal terrestrial levels (and not requiring , say, a 400kw tx dish..) it could drastically increases the utility of the link -- and all of this without discussing how much bandwidth a link network across the stars might possess compared to our current link to Voyager.. (this is all said with the presumption of a reason to have such distance communications channels.. )
- LargeWu 11mo agoSeems like the problem OP is trying to solve for here is not latency, it's signal power and redundancy.
- glenstein 11mo agoYou're exactly right and thank you for carefully reading! I very explicitly said that there was a multi year round trip for information even in the best case (e.g. Alpha Centauri), to get out ahead of the well-actually's. As you noted, some of the gains could be signal power, redundancy, the ability to maintain a quality signal over arbitrary distance; but most importantly, seeing the universe from the perspective of the lead probe in the relay, some arbitrary distance away.
- deleted 11mo ago[deleted]
- tpurves 11mo agoWhat 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.
- Tepix 11mo agoIndeed. 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.
- trhway 11mo agoSun 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).
- Spare_account 11mo agoFor anyone interested, this is approximately the wait/walk dilemma, specifically the interstellar travel subset: https://en.wikipedia.org/wiki/Wait/walk_dilemma#Interstellar_travel 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.
- omoikane 11mo agoI wonder if we can go the reverse direction, where instead of launching more probes from Earth to serve as relays, the spacecraft would launch physical media toward Earth packed with whatever data it has collected. Given advancements in data storage density, we could achieve higher bandwidth than what's possible with radios. The logistics would be difficult since it involves catch those flying media, especially if the spacecraft were ejecting them as a form of propulsion, they might not even be flying toward Earth. I was just thinking how early spy satellites would drop physical film, and maybe there are some old ideas like those that are still worth trying today.
- mcdonje 11mo agoI think they're working on laser data transmission.
- iainmerrick 11mo agoThe spacecraft is moving away from the sun at escape velocity. How is it going to launch anything backwards and have it make it all the way back to earth?
- brador 11mo agoBinary encoding by pulsing the ion stream. Then picking that up with terrestrial telescopes. Very clever!
- _jzlw 11mo agoSmoke signals in space. I love it.
- threethirtytwo 11mo agoNo 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.
- sph 11mo agoBased on what? That we will never be able to make probes travelling faster than ~17km/s (relative to the Sun) that will eventually reach and overtake Voyager 1? I certainly wouldn't bet against technological progress, and I say that as a complete doomer.
- gregable 11mo agoWell voyager depended on a solar system alignment that only happens every 175 years(?) so it'd be a while before we get that same advantage again. The longer it takes the further of a head start voyager gets?
- phkahler 11mo agoStarship could be refueled in orbit. That should then be able to reach those kind of velocities with enough capacity to even include a small 3rd stage inside with the payload.
- kentm 11mo agoYeah, Voyager 1 was launched on a Titan IIIE. I don't really want to do the delta v calculations, but if we look at mass to LEO as a rough proxy, Titan IIIE does 15,400 kg and the Falcon Heavy does around 50,000 kg (with re-use). New Glenn can apparently do 45,000 kg. Doesn't take into account gravity assists, but 3x the capacity before Falcon Superheavy or refueling gives us a helluva lot of leeway. Its not "interstellar speeds" but I'm pretty sure we could get probes further out than Voyager 1 faster if we put the money behind it.
- Mogzol 11mo agoThe headstart doesn't really matter, anything faster than Voyager will catch up eventually
- zamadatix 11mo agoWith current probes being so "slow" (peak speed of the Voyager probes was on the order of 0.005% the speed of light) I wonder if even doing 10 probes at once per decade gets you more data back than working towards faster probe for less total time. You could use this to create a relay in reverse order, but I also wonder if having a 50-100 year old relay would be any better than just using modern tech directly on the newest, fastest probe and then moving on to the next when there are enough improvements.
- wkat4242 11mo agoWell, the voyager power source is still pretty good. But as I understand it the thermocouple that converts heat to electricity has degraded. Because the Pu-238 half life is 87 years so they wouldn't even be down to half yet..
- looofooo0 11mo agoAmericium battery could last a lot longer.
- georgefrowny 11mo agoMy intuition is that the extra mass for the receivers would be a large negative in terms of travel time (1/sqrt(m) penalty assuming you can give each probe fixed kinetic energy). Plus keeping a probe as active part of a relay is a major power drain, since it will have to be active for a substantial percentage of the whole multi-decade journey and there's basically no accessible energy in interstellar space. Then again, it's still far from clear to me that sending any signal from a probe only a few grams in size can be received at Earth with any plausible receiver, lasers or not.
- glenstein 11mo agoThoughtful intuitions all around. My understanding is that lasers don't necessitate the big reception dish, but instead have a 1m or smaller reflective telescope. The laser setup is lighter, lower power and gas precedent in modern space missions. Probes I suspect would realistically have to be large enough to send strong signals over long distances, so weightier than a few grams. I think 99% downtime is an existing paradigm for lots of space stuff, e.g. NASA's DSOC and KRUSTY, so room for optimism there. Though I think I agree with you that an energy payload as well as general hardware reliability are probably the bottlenecks over long distances. I have more thoughts on this that probably deserve a seperate post (e.g. periodic zipper-style replacements that cascade through the whole relay line) but to keep this on honoring the Voyager, I will say for the Voyager is at least for me huge for opening my imagination for next steps inspired by it.
- georgefrowny 11mo agoI also spend far too much time wondering about sending out swarms of probes and if you could somehow rendezvous them and add fuel midjourney and so on! The problem I see is that lasers are still subject to diffraction, and this is worse the smaller the aperture is relative to wavelength. Due to the small probe mass which you need to split with observation equipment, support systems and presumably some microscale nuclear power supply, you could maybe with a few breakthroughs in engineering manage a wispy affair on the order of a metre at most. It it scales with diameter and mass scales with diameter squared. So the beam divergence of a visible light laser end with a diameter of over 18 million km over 4 light years. With 100W of transmission power, that's 0.1pW per square kilometer of receiver. Which isn't nothing, but it's not huge either. I really don't see how the Starwisp type microprobes will actually work on a practical level at any time in the foreseeable future, even if the propulsion works. Not only is the communications a problem, but so is power, computational resources, observation equipment, radiation shielding and everything in between. But anything massier than that requires mindboggling amounts of fuel. And the problem is so much worse if you want to stop at the destination rather than scream past at a modest fraction of c and hope to snap a photo on the way past. It really seems (sadly, in a way) that building gigantic telescopes will be a lot more instructive than any plausible probe for quite some time. An gravitational lens telescope would be a far better, and probably almost as challenging, project for learning about exoplanets. Not least it would be about 3 times further from Earth than Voyagers.
- colechristensen 11mo agoThis is a link budget problem. A probe has to have a certain transmit power, receive sensitivity, physical size, fuel for orientation, etc. So you have to come up with the optimums there were it makes sense at all which isn't easy, especially compared to having one big station near earth that communicates point to point with the deep space whatever. It might just have to be much too big to be worth it in the next n centuries. If humans settle Mars it'll probably make sense to build one there for marginal improvement and better coverage with the different orbits of Earth and Mars.
- __loam 11mo agoThat's how the mongols communicated but with guys on horses.
- boisterousness 11mo agoCould a probe return data by semaphore? Wave a flag that blocks the light of Alpha Centauri as seen from a telescope off to the side of the sun, say at the distance of Neptune's orbit. It should be possible to hide Alpha Centauri behind a relatively small semaphore until the probe gets fairly close.
- hcs 11mo agoNeat idea, but it looks like the math doesn't really work out: https://space.stackexchange.com/questions/66295/is-interstellar-communications-by-transit-ray-blocking-dark-star-novel-plau https://space.stackexchange.com/questions/66295/is-interstel... Though it looks like these folks are thinking about blocking from near the star, which requires megastructures for anything detectable. I haven't done even back of the envelope calculations but I'd guess the limiting factor is you'd only be causing an eclipse/transit in an unusably narrow angle directly behind the craft. As you get closer the cone expands but the signal weakens.
- sllabres 11mo agoI think only the Grand Tour program was possible every 175 years: From Wikipedia [1]: "that an alignment of Jupiter, Saturn, Uranus, and Neptune that would occur in the late 1970s would enable a single spacecraft to visit all of the outer planets by using gravity assists." Gravity assists with more than one planet are more frequent. Cassini-Huygens [2] as example had five (Venus, Venus, Earth, Jupiter, Saturn) I would suspect when the goal ist only to leave the solar system as fast as possible (and don't reach a specific planet) they are much more often. [1] https://en.wikipedia.org/wiki/Grand_Tour_program https://en.wikipedia.org/wiki/Grand_Tour_program [2] https://en.wikipedia.org/wiki/Cassini%E2%80%93Huygens https://en.wikipedia.org/wiki/Cassini%E2%80%93Huygens
- deleted 11mo ago[deleted]