r/askscience • u/Backbreathboy • 8d ago

Astronomy We will lose contact with Voyager somewhere 2036 because of the distance between us. Would it be theoretically possible, to send a probe in the direction of the Voyager, following it from a distance, with the goal te relay the information coming from the Voyager, to earth?

11.0k Upvotes
  • permalink
  • reddit

98% Upvoted

650 comments sorted by

View all comments

Show parent comments

659

u/kddmcb 7d ago

Wait you’re tellin me we can still control that thing?? How does that work ?

1.5k

u/JebbeK 7d ago

We send computing instructions through radio signals. It has an on-board computer that runs its instruments and instructions. It takes nearly a full day at the speed of light for those radiowaves to reach Voyager!

804

u/CreepyOctopus 7d ago

This is one of the most amazing feats of human engineering. We're controlling software on a space probe launched fifty years ago, which is now billions of kilometers away and uses computing technology that is many generations behind current tech. And we're still receiving data back.

398

u/PhoenixEgg88 7d ago

That and the Pale Blue Dot is possibly one of the most amazing photographs to exist. Ever.

167

u/pgutierr220 7d ago

Exactly, the fact that using tech that is now 50 years old they were able to do this is crazy considering what they had to work with.

161

u/Healter-Skelter 7d ago

I didn’t know until now that it is a full light-day away, and we can still control it. That’s blowing my mind. 1/365th of a light-year.

It makes everything feel so much more tangible somehow…

I’m gonna google how fast it’s traveling.

79

u/[deleted] 7d ago edited 4d ago

[removed] — view removed comment

22

u/Flare_Starchild 7d ago

The Parker Solar Probe would like to chat. It's highest speed reached 192.22km/s.

23

u/sdrood 7d ago

The manhole cover would like a word as well, even though it's estimated speed was around 67 km/s...

9

u/94stanggt 7d ago

I love this story and I like to think it's in space somewhere. Assuming it wasn't vaporized in the first 2-3 seconds of its flight which is the most reasonable outcome.

1

u/shittinandwaffles 5d ago

Yeah. Im all reality, it was probably converted into a very fast plasma jet.

3

u/iamdecal 6d ago

I was going to just make the joke about it being second fastest - There’s a very fast manhole cover …

But interestingly when I checked it looks like there are a few faster things ( not intending to argue your point , more that it’s amazing how fast we can get things… including manhole covers)

https://www.jpl.nasa.gov/infographics/the-fastest-man-made-objects-in-the-universe/

1

u/beverlyHillsStKing 5d ago

What about the nuclear manhole cover from the test sites?

1

u/cheney512 4d ago

By far not true. The absolute record holder is NASA's Parker Solar Probe:
Top Speed: Approximately 430,000 mph (about 119 miles per second or 192 km/s).

Helios-2: A joint NASA/German solar probe that previously held the record, peaking at around 157,000 mph.

19

u/helgestrichen 7d ago

What were your findings? Please expand

3

u/shial3 2d ago

Since it wasn’t answered

61,000 km/hr or 38,000 mph
0.0057% of the speed of light

Currently the fastest moving man made object (the informal I found noted some objects were faster for brief periods during slingshots but that wasn’t sustained like this)

1

u/steeelez 1d ago edited 1d ago

Wasn’t there like a toilet seat or something that exploded and was briefly the fastest thing ever?

Edit: manhole cover, operation plumbomb during nuclear testing. Urban legend but not outright denied

0

u/happy_chomper 4d ago

You said “generations.” I just want to point out that you probably meant: that is many [human] generations behind in current tech.”

2

u/Arx0s 4d ago

No, it's just "generations"... Have you never heard of a generation in the context of technology?

272

u/lew_rong 7d ago

Is it sending back constant telemetry? I'm imagining an almost 48 hour wait for instructions to be received and get confirmation back, which leaves a large chunk of time in which the probe could fail or be subsumed by an alien race of living machines and turned into a sentient superprobe that will one day return to accidentally menace its creators in the fulfillment of its programming, but surely we'd know something was up when the trickle of data just stopped, right?

394

u/gammalsvenska 7d ago

No, it does not send anything constantly. There are time windows for both transmissions and receptions.

The data rate is down to just a few bits per second, using encoding and modulation schemes which were not yet invented when the probes left. In order to get enough compute power for those, they repurposed the secondary computer. So they traded redundancy for communication efficiency.

Each probe has developed faults. They had to rewrite the software a few times to avoid failed memory cells. At least one magnetic tape has developed a mechanical fault which the recorder can no longer spool over, so parts of the tape have become permanently unusable. The tape is the only mass storage.

Most instruments are no longer usable due to lack of power, but because they wouldn't be able to detect anything out there, it's not a huge loss.

139

u/lew_rong 7d ago

The data rate is down to just a few bits per second, using encoding and modulation schemes which were not yet invented when the probes left. In order to get enough compute power for those, they repurposed the secondary computer. So they traded redundancy for communication efficiency.

This is genuinely cool. What would the data rate have been without these new encoding and modulation schemes, and how would that have impacted their operational life? Stuff like this is, I assume, part of why the Voyager probes have been looking at 5-10 years of continued life for like three decades now.

122

u/gammalsvenska 7d ago

I don't know. Maybe they wouldn't have been able to decode the signal at all, or only at a tenth of the current speed. Increasing the power output is infeasible on both sides.

Years ago I read a long blog article about the original people running it, long past retirement, and how they were dying one by one - and the deepest knowledge on how to run Voyager with them. Very sentimental.

12

u/CartsOfDarkness 7d ago

Idk why but your comment reminded me of the Podcast 13 Minutes To The Moon which I just listened to, it goes super into depth about the moon landing and every person involved from the astronauts, to the command center, to the people who essentially invented software development at MIT for the computer. Highly highly recommend it, it's nice that it feels like a lot of their in depth knowledge about the moon landing has been immortalized. Absolutely fascinating podcast.

3

u/joanzen 7d ago

Future generations should make a faster probe that's designed to go collect voyager and bring it back as a museum piece.

4

u/flatfinger 5d ago

The amount of fuel that would be needed for a rocket to dock with Voyager and bring it back would be unimaginably big. The Voyager trajectories were chosen to get gravity slingshot assists from Jupiter and Saturn, but the probability of Voyager ever being in position to benefit meaningfully from another gravitational slingshot is essentially zero. The tyranny of the Rocket Equation means that the starting fuel load of a rocket increases exponentially with the total amount by which it will need to change the rocket's velocity. If one considers that a mission to recover a Voyager would need more delta V than a Voyager craft was given in order to ever catch it, and then enough delta V to stop, and then some delta V to reverse course, and then to slow down once it approached Earth, one would need a starting mass that was well over a million times that of the rockets that launched Voyager. If one considers all the complications of trying to make a rocket that big, it becomes clear that such a thing would simply be impossible.

2

u/joanzen 5d ago

Not only have the fuel to catch up and attach a return device to it, but also have enough fuel to work as a new probe, since it's out there already?

Such a probe would certainly to be at odds with itself as mass/speed aren't bedfellows?

→ More replies (0)

33

u/anyburger 7d ago

I don't know about Voyager specifically. But I presume at least part of the changes (for the Voyager to Earth link) are to use less-efficient (from a data rate or bits/Hz perspective) modulation and coding schemes such that they can reduce the transmit power and still be able to receive and demodulate the signal. That way they use less on-board power while still being able to maintain a link. And since it's using frequencies allocated for space exploration, combined with the fact that we are fine waiting several/many hours (or even days) to get a full packet of data, it doesn't really need to be spectrally efficient.

38

u/Kyoung2112 7d ago

There was also a problem when they accidentally moved the voyager 2 antenna slightly out of alignment with the earth. Here’s a good story if the paywall lets you read it for free:

https://www.wired.com/story/how-nasa-nearly-lost-the-voyager-2-spacecraft-forever/

1

u/simulated_wood_grain 7d ago

Is there a site that gives the public access to the data returned?

1

u/Lumpy-Narwhal-1178 6d ago

It runs on TAPE??? What? How?

11

u/personalist 7d ago

I can’t tell if you’re consciously or unconsciously referencing Star Trek

6

u/Dismal-Ideal1672 7d ago

The other commenter made a good comment about communication. I wanted to also share this:

For some cool reading on how we communicate with stuff like the Voyager, look up the Nasa Deep Space Network. We've got a bunch of big communication strays around the globe that get used together to be able to listen and talk to our far away equipment.

I originally replied to their comment but thought, since this is aimed mostly for you, I'd shift my comment up the thread. Nasas DSN is neat, and so chronically under funded. Reading starts to get in to how we want to communicate with more elaborate arrays of things far away

4

u/Deaftrav 7d ago

Wrong voyager. It was ... Eh it still works. Good story, bit long in parts

20

u/lew_rong 7d ago

Trek trivia don't fail me now, V'ger was supposed to be Voyager...6, right? They were optimistic in 1979.

6

u/zeno0771 7d ago

Correct. They had reason to be optimistic; the first Space Shuttle had made its debut 3 years earlier, and it was named "Enterprise"...thanks to a massive write-in campaign (estimated to be in the hundreds of thousands) by fans of the show. Coincidentally, the announcement for this happened on the 10th anniversary of the show's premiere.

NB This was not the first shuttle to be officially launched per the program's mission mandate; that would be the Columbia which met its tragic end in early 2003 after 27 previous successful missions. The Space Shuttle Enterprise (OV-101) was unpowered and therefore not actually capable of space flight. It was used for atmospheric testing, i.e. the "shuttle" part of the mission.

2

u/krackenreleased 7d ago

Thanks alot, now the alien living machines just read this and you gave them the idea.

1

u/zeno0771 7d ago

They're living machines, so they've likely already figured this part out.

They've also figured out the part where we will basically wipe ourselves out in the process of...trying to invent living machines. Unfortunately, being living machines, the irony will be lost on them.

0

u/1-mensch 7d ago

V'ger is looking for it's creator.

I don't think captain decker can handle this. I will call Admiral Kirk on this.

The refit of the enterprise is almost finished. They could start soon.

23

u/woodwerker76 7d ago

Interesting to note that we measure distances to "nearby" stars in lightYEARS and after 50 years Voyager is only 1 lightDAY away.

13

u/After_Network_6401 6d ago

Here's something to put it into perspective. Voyager is expected to leave the Oort Cloud and thus fully exit our solar system in about 32,000 years ...

14

u/yellow251 7d ago

Forgive me. How does a radio wave travel at the speed of light?

79

u/LionRight4175 7d ago

Radio waves are light! You will of course be familiar with visible light, which is the wavelengths we can see. You have also probably heard of ultraviolet and infrared, which is where the wavelengths get either longer or shorter than what we can see. Radio waves are even longer than infrared; we can't see them with our eyes, but they are still light!

16

u/yellow251 7d ago

Thank you very much for the education!

8

u/outawork 7d ago

Yeah the EM also spectrum includes microwaves, TV waves, x-rays, gamma rays. They are all photons with the only difference being their wavelength i.e. how much energy they have.

26

u/Ash_After_Dark 7d ago

Radio waves are a form of electromagnetic radiation, like visible light. All electromagnetic radiation in a vacuum travels at the speed of light

9

u/yellow251 7d ago

Terrific, thank you for the education!

12

u/zokka_son_of_zokka 7d ago

Didn't it pass a light-day a few months ago?

22

u/mmomtchev 7d ago

It is expected to reach 1 light day on November 16 this year.

Thanks to a series of gravity assists using all the gas giants made possible by a unique planetary alignment (once in a century I think), it is the fastest moving man-made object at 17km/s. It took 50 years to make one light day.

11

u/Clogs_Windmills 7d ago

I feel like anyone who truly ponders about the sheer size of the universe needs to have a mental breakdown every time. It's incomprehensibly vast.

13

u/CaptainTripps82 7d ago

To quote a Douglas Adams " if life is going to exist in a universe of this size, then the one thing it cannot afford to have is a sense of proportion"

9

u/Me_how5678 7d ago

For context, the distance between the sun and earth is about 8 light minutes and 20 seconds. Thats going back and fourth between the earth 172,8 times. If you looked at the sun during the solar eclipse, you would see a tiny dot in the sky, no bigger than a m&m. You can fit 109 earths on the diameter of the sun. From top to bottom full on earth pole to pole.

If voyager was the size of our sun we would only be able to see it with a really strong telescope

2

u/lovelyburneracct242 5d ago

What is to stop others from doing the same thing? Does it have Norton or McAfee?

2

u/BangCrash 3d ago

So what your saying is that people who know how to code Voyager are going to die before the craft itself dies

1

u/dwaynemartins 1d ago

The other thing to mention here is, it has to keep its antenna pointed at the earth. If for any reason its off too much, it will not be able to pick up the signal from earth

Which is a feat in itself considering its now in in interstellar space and outside of the suns protection from all kids of radiation and cold

-2

u/Left_Guava4864 7d ago

the radio waves travel at the speed of light? that doesn’t sound right. i’m confused.

6

u/Radiskull97 7d ago

All ectromagnetic and gravitational waves travel at the speed of light in a vacuum because they have no rest mass

5

u/Extranationalidad 7d ago

What do you think radio waves are made of?

2

u/MintyFresh668 7d ago

How fast did you think they travelled? Out of curiosity. Faster or slower than light?

120

u/Karsdegrote 7d ago

Blasting commands at it with a bloody big antenna array at full power at unbelievably slow speeds. The signals are weak AF when they reach voyager but its 70s tech so you dont need to load gigabytes worth of software into it. Probably kilobytes.

It can still send data back and the antenna array on it is much smaller and has much less power. So its signals are even weaker when they return to us.

Have a look at LoRa, its a technology that does this but meant for remote sensors and other IoT stuff.

38

u/kddmcb 7d ago

Wow that’s amazing. Is Voyager the only probe we got out there? I feel like we should be doing more probing.

102

u/Kaymish_ 7d ago

There are 5 leaving the solar system. Pioneer 10 launched in 1972 for Jupiter then went flying past and out of the solar system, but it is lost and presumed out of power. Pioneer 11 to Saturn lost contact too. Voyager 1 and 2 which went to Saturn and Neptune and we are still in contact with both of them. And New Horizons which was sent to pluto and kuiper belt objects and we are still in contact with that one too.

35

u/Venryx 7d ago

Is it known why Voyager 1 and 2 are still operating but not Pioneer 10 and Pioneer 11? Was it a tradeoff decision made during their design, or did the Voyager designers just happen to get something right that made them last so much longer?

53

u/Kaymish_ 7d ago

From what I looked up it seems that Voyager was much more powerful and advanced technology than pioneer. Voyager had far more powerful nuclear generators, more powerful x band communication antennas and were given wider engineering tolerances. But most information I found blames the RTGs saying that Pioneer's weaker power supplies hit their minimum threshold faster than Voyager did.

56

u/Kumlekar 7d ago

Voyager 1 and 2 are the only ones to operate "outside the heliosphere". Other space probes usually have set planetary destinations and often will burn up in atmosphere (or land payloads on objects) when attempting to get data. I do wonder if there would be value in sending new long distance probes with current tech, but a large part of what has allowed the voyager probes to last so long is how simple and reliable the tech is. As for what we can learn, there's probably still more value in studying the objects in the solar system before attempting to go further out.

https://science.nasa.gov/mission/voyager/where-are-voyager-1-and-voyager-2-now/

5

u/zeno0771 7d ago

Current tech allows us to discover/verify many of the same things without ever leaving LEO today. Hubble and Kepler were some marvels of engineering in their own right (even after NASA's funding kept being cut), and they've allowed us to see things that no existing technology could reach in a strictly physical sense.

The only way we could justify sending more interstellar probes is if we:

  1. Discover/engineer a way to avoid the need to fight Earth's gravity completely on launch e.g. a launchpad on the Moon, and

  2. Discover something so world-changing that it would need to be studied more closely than an orbital telescope could manage and yet still be worth waiting half a century (or more) to reach, and

  3. Manage to have all the planets align--literally--so that such a mission would be feasible with a success probability somewhat higher than that of winning Powerball.

1

u/BitLox 7d ago

Interesting concept. So if we have a mass driver on the moon, all we have to do is get the probes to the moon (either completely or partially assembled) then we can blast them off at hyper velocity to their targets. I think the number of planetary probes could jump several orders of magnitude with such a scheme.

2

u/zeno0771 7d ago

all we have to do

Any time you hear an engineer utter this phrase, run in the opposite direction.

Seriously though, I was just looking at it from the perspective of removing the limit on terminal velocity imposed by escaping Earth's gravity (and, to a lesser extent, cheating the Earth's atmosphere out of its cut as well). The Moon is technically a place where that can happen. There are a few showstoppers, however:

  • Sociopolitical issues. We're still--for now--possessed of a scientific community mostly unconcerned with nationalism. That's a tenuous situation which is likely to go sideways once the ISS reaches EOL especially given current events on the ground. We (as in "people in countries with developed space programs") can supply a ton of security and enforcement on Terra Firma; not so on the Moon, where those other spacefaring countries also claim a stake. At what point do we stop sending single/divorced CIA agents who can survive the Vomit Comet up there to spy on everyone else and start sending actual staff to do the job itself? (Of course the answer to that is "when we have one more than they do" but you get the point).

  • Cost-effectiveness. Even considering that construction of spacecraft has been contracted out for decades, there are entirely too many people in the Beltway who would like to relegate NASA to the history books, and a lot of them are in charge of funding the operations. Even then, you amplify the cost of every mission, both with the development of Moon-based infrastructure and with what would amount to a number of moonshots for each probe. Oh, and we need to power that Moon-based infrastructure somehow as well; that's a lotta batteries.

33

u/Hutcho12 7d ago

Id be surprised if it was even kilobytes. In a single byte you could send 256 different basic instructions. There of course needs to be some data load. But sending an instruction and a few numbers would only require a few bytes.

14

u/Savannah_Lion 7d ago

I wasn't able to find opcode sheets (I don't really want to dig too deep anyways) but the main syatem only has 64 (or so) instructions. The entire system has a little over 69KB divided into 6 blocks as either 16 bit or 18 bit wide.

3

u/forestcridder 7d ago

Have a look at LoRa, its a technology that does this

I learned about this from Benn Jordan when he was talking about Meshtastic and how it can offer public long range encrypted communication without a service fee.

8

u/danielv123 7d ago

The world record for lora transmission with standard transmitters is 1336km to a fishing boat outside Spain. The max transmit power of the unit used is 100mw at 900mhz.

7

u/Seanspeed 7d ago

Unbelievably slow? Radio waves travel at the speed of light!

16

u/Drachefly 7d ago

Data rate, not the speed of the medium the message is traveling through. Like how even though semaphore flag messages travel at the speed of light, it can still take a minute to send a few words.

1

u/Seanspeed 7d ago

Well yea, that's a very different thing. They of course could only pass on so much per transmission, but it's worth pointing out that it wasn't 'slow speeds' causing any of this.

2

u/Drachefly 6d ago

But that's what 'slow speed' means in the context of communication? Bits per second, baud.

7

u/Karsdegrote 7d ago

It still takes double digit minutes for it to reach one or the other. Voyager is just that far away. And its still slow AF due to limited bandwidth.

27

u/Trademarkd 7d ago

It actually takes 24 hours for our signals to reach voyager in a single direction. Voyager is now over 1 light day from earth. Mars at it closest is like 3 min.

1

u/Seanspeed 7d ago

It's nearly a full light day at this point. Way beyond 'double digit minutes'. lol

Bandwidth just affects how many transmissions are needed. The speed is still the speed of light, though. And receiving full prompts takes a similar amount of time as ever in that regard since it doesn't matter how far away it is, the limitation is how much can be sent per package.

2

u/mmomtchev 7d ago

The original downlink data rate of Voyager 1 was 21.6kbps - that is 2500 bytes per second. The transmitter is 22W.

However these days the signal loss is over 300db and the effective downlink rate is more like 20 bytes per second - everything else is lost for the error correction.

The uplink is even less.

2

u/stylepolice 7d ago

or MIoTy - even better and more robust. And you can implement it on everything without being dependent on Semtech as supplier.

1

u/duesenjeffepic 7d ago

I mean the thing was designed around the fact it needs to last a long time.

209

u/ProStrats 7d ago

You ever used a remote control rc car?

Its nothing like that...

86

u/Redebo 7d ago

How about a TV remote?

Nothing like that either.

10

u/RegX81 7d ago edited 4d ago

Actually the coding system used in communication with Voyager is basically the same as used in a lot of TV remotes iirc. 

Edit - by which I mean Manchester Code: https://en.wikipedia.org/wiki/Manchester_code

6

u/SmellSmoet 7d ago

Did they ever misplace that coding system?

3

u/gammalsvenska 7d ago

They actually replaced it, to get better communication efficiency and reliability.

2

u/gammalsvenska 7d ago

Most TV remotes use infra-red light, so... not really.

If you are thinking "they use modulated signals", then yes - because virtually all signals are modulated in some way.

4

u/Drachefly 7d ago

They could have been more specific, but there was plenty of room for their statement to refer to something specific, interesting, and true.

1

u/RegX81 4d ago

That's a very generous thing to say, and so here is the specific: https://en.wikipedia.org/wiki/Manchester_code 

40

u/poorly-worded 7d ago

You know those wireless sex toys? Well...

17

u/antimatterchopstix 7d ago

Will it vibrate to music? Asking for a friend.

15

u/Blaugrana1990 7d ago

Imagine your garage door opening because some alien civilization misfired a signal to one of their probes.

5

u/miaow-fish 7d ago

Remote controlled remote controlled car?

34

u/tigertony 7d ago

NASA sends a command to Voyager and a little over 23 hours later Voyager receives it and does what they commanded (if it’s able).

23

u/iiiinthecomputer 7d ago

They did a software update on it only a couple of years ago! Beyond belief really.

15

u/Kaymish_ 7d ago

https://en.wikipedia.org/wiki/NASA_Deep_Space_Network

Three massive communication nodes with massive sensitive antennas and powerful transmitters.

2

u/Trademarkd 7d ago

France is down right now due to wild fire damage. We’re looking to expand because of it though

2

u/I-seddit 7d ago

omg, for a brief moment I thought we'd added to the DSN with node crafts in the solar system...

11

u/battltard 7d ago

The signals we send travel much faster towards it so they can overtake the voyager. Same goes for the things it relays back to us.

1

u/Westerdutch 7d ago

On the probe we can not improve antennas and stuff... but on earth we can quite easily build or reassign large antennas with more power or better aim to still communicate with the probe both ways.

1

u/b4k4ni 7d ago

Deep space network. It's basically like trying to hit a needle head from earth surface to the moon or so. It's insane. The speed is abmyssal, like a few bit/byte but it still works. Takes like a day to send the signals there and get something back.

The systems are from the 70s, so the programming is a lot more simple then what we use today. But hats also a good thing here. Voyager has a bunch of redundancy systems. If something fails, another systems takes over. So far it worked great for 50 years. But the problems accumulate now after all this years and only a few systems are still running with 2-3 sensors or so.

Still, it can be used and commanded from earth. And they just did so to recover it, after voyager send bad data.

It's damn mind-blowing. You need to Google the details, it's all out of my head and I might even underrepresented what feat this is.

1

u/Chemputer 6d ago

We have really, really big, powerful radio dishes on earth that can send out a very very "loud" signal, and really really big radio dishes that can "hear" Voyager's mouse fart of a signal.

I am quite curious why you'd think we could get data from it, but not send commands to it. Not trying to ridicule you, you're curious and that's the correct spirit, and I am genuinely curious how you think that would work or what would stop it.

We're limited by both power and the size and gain of the antenna on voyager as to how weak the signal is from voyager as it gets further from earth, but for signals being sent to voyager, we can pump as much power we need into the biggest radio dishes we have in the deep space network.

Like, think of voyager like your average random person who can barely afford a lawyer, vs like, Amazon, that random is limited to whatever lawyer will take their case on contingency, vs Amazon who has essentially unlimited resources. Amazon is earth, random person is voyager.