Voyager I reaches edge of solar wind

January 19, 2011 12:00 AM

The Voyager I spacecraft, 33 years into its mission, "has outrun the solar wind" and is exiting the solar system. This nice article explains what this means, and has a bunch of wonderful details and interviews with the original mission scientists.

The announcement about the solar wind was made a month or so ago, and the "exiting" is taking place over a few years, so it's not like a "mark this date in your calendar" scenario. I'm posting it mainly because I really enjoyed this particular article on it. The article is by Frank Roylance of the Baltimore Sun, and it gave me the good old sense of wonder.

posted by LobsterMitten (70 comments total)

Interesting article.

It's still working, more than 5 million "steps" later. "I bet that motor is probably the longest, continuously operating device in space, ever," he said.

I bet it isn't.
posted by weapons-grade pandemonium at 12:12 AM on January 19, 2011 [21 favorites]

I wonder if we'll develop the capability to go and retrieve those devices within 296,000 years. Their historical value alone may make it worthwhile, even if they'd be destined to gather dust in some hyper-rich, intergalactic plutocrat's personal collection.
posted by Silverdragonanon at 12:18 AM on January 19, 2011 [1 favorite]

Great piece, so inspiring and humbling at the same time. If only such foresight, planning and creativity were present in all government funded projects.
posted by smoke at 12:18 AM on January 19, 2011 [4 favorites]

I just love this. Nerds rule.
posted by vanar sena at 12:46 AM on January 19, 2011 [4 favorites]

A trillion years from now on a distant planet, a primitive apelike species will witness a flash of light and an explosion in the trees. They'll run toward Voyager's smouldering remains and they'll dance and shout and burn their hands and we'll get another go at civilisation.
posted by doublehappy at 12:49 AM on January 19, 2011 [10 favorites]

Silverdragonanon, I'm pretty sure we could go out and collect the Voyager spacecraft right now, although it would take a fair amount of work. You'd need money and engineering, but not physics breakthroughs.
posted by ryanrs at 1:00 AM on January 19, 2011

NASA release.
posted by IvoShandor at 1:05 AM on January 19, 2011

ryanrs, how exactly could we collect the Voyager spacecraft? It might be theoretically possible but it's way beyond our current capabilities.
posted by salmacis at 1:20 AM on January 19, 2011

even if they'd be destined to gather dust in some hyper-rich, intergalactic plutocrat's personal collection.

Like the first laser gun, it would provide great fodder for a heist.
posted by flaterik at 1:22 AM on January 19, 2011 [7 favorites]

I would like to take this opportunity to thank Voyager I (& II) for the wealth of pioneering close-up planetary photographs that fed my space hunger during the lean years following the premature death of the classic space age.
posted by fairmettle at 2:07 AM on January 19, 2011 [6 favorites]

A trillion years from now on a distant planet, a primitive apelike species will witness a flash of light and an explosion in the trees. They'll run toward Voyager's smouldering remains and they'll dance and shout and burn their hands and we'll get another go at civilisation.

2001 had been out since 1968 and we still didn't send a giant obelisk through space. Sometimes I doubt humanity's commitment to inside jokes.
posted by ersatz at 3:04 AM on January 19, 2011 [15 favorites]

Congratulations, humankind. We have now littered where no man has littered before. (Minimum fine for intersidereal littering 250×10¹⁰⁰ spacebucks.)
posted by XMLicious at 3:13 AM on January 19, 2011 [1 favorite]

How fast is Voyager traveling?
posted by Kilovolt at 3:28 AM on January 19, 2011

How fast is Voyager traveling?

Not fast enough, in my opinion.
posted by LiteOpera at 3:58 AM on January 19, 2011 [1 favorite]

Wikipedia says: "Voyager 1's current relative velocity is 17.07 km/s, or 61,452 kilometres per hour (38,185 mph). This calculates as 3.6 AU per year, about 10% faster than Voyager 2. At this velocity, 73,600 years would pass before reaching the nearest star, Proxima Centauri, were the spacecraft traveling in the direction of that star."
posted by knave at 4:03 AM on January 19, 2011 [1 favorite]

Well, that puts my mind at rest - proof at last that we're not in a pocket universe (well at least not in my favourite literary pocket universe).

I was so worried about the dents Voyager was going to get when it hit the edges...
posted by KirkpatrickMac at 4:09 AM on January 19, 2011 [2 favorites]

KirkpatrickMac: Or indeed a Crystal Sphere.

Although you all realise that as soon a Voyager gets past a certain point, our alien overseers will deem us too advanced, and destroy us. The Mayans knew this.
posted by seanyboy at 4:37 AM on January 19, 2011 [2 favorites]

They had an article about this on Channel 4 News (UK) some while ago, and it was interesting that the interviewer couldn't get his head around the fact that Voyager is essentially drifting out of our solar system. He seemed amazed that any vehicle could travel so far considering the current cost of petrol (gas).
posted by seanyboy at 4:40 AM on January 19, 2011

were the spacecraft traveling in the direction of that star.

Oh, I could get there. If I wanted to.
posted by blue_beetle at 4:44 AM on January 19, 2011

ryanrs, how exactly could we collect the Voyager spacecraft

Glad you asked! We can retrieve a Voyager spacecraft in 3 easy steps! (plus a hard one)

1) Send a probe to intercept the Voyager craft. This is easy because we know where it is and it's not accelerating away from us. The target craft is proof that we can do this.

2) Match speed with the target and grab it. Also easy since the velocities are similar and the target is transmitting a radio beacon.

3) Turn around and head back to Earth. Not so easy.

4) Decelerate and enter Earth orbit. Easy, I think.
Note: I don't understand gravitational slingshots in any great detail, but if they can speed stuff up on the way out, they ought to be able to slow stuff down on the way back. Presumably some careful planning will be necessary.

Of these four steps, only the third one is difficult. It requires a phenomenal amount of delta-v, over 30 km/s. But there are various experimental ion drives that have sufficiently high specific impulse and thrust for this mission. Either HiPEP or VASIMR, for example. You'd also need a nuclear reactor for power; radioisotope thermal generators won't cut it.


I stand by my statement that this mission is possible with technology that's already being tested today. That said, I certainly don't believe this would be a good or worthwhile mission. Quite the opposite, in fact. Putting those golden records on display at the Smithsonian would be the greatest tragedy in the history of space exploration. Those records don't belong in a museum. At least not one on Earth.
posted by ryanrs at 4:44 AM on January 19, 2011 [16 favorites]

250×10¹⁰⁰ spacebucks

Is 2,500 a lot? (xe.com didn't have the exchange rate for spacebucks)
posted by ryanrs at 4:54 AM on January 19, 2011

...proof at last that we're not in a pocket universe...

Are you sure? I have this one in my pocket (actually on my belt) so we might all be in an app on some other being's mobile device, just as they are in an app in some even greater being's device, and so on ad infinitum.

Interesting article; we went to a planetarium while on vacation over Christmas and the presenter made the same point about Voyager. But it seems rather arbitrary to me; in the same presentation she made the point that the gravitational limit of the solar system is defined by the Oort Cloud, which makes it a better marker for the edge of the solar system.

That quibble aside, though, the Voyagers and their story is a fascinating one. It makes me glad to see them noticed from time to time in the media. NPR has stories on it on a regular basis. I particularly liked this one.
posted by TedW at 5:26 AM on January 19, 2011

I was such a nerd that I used to race home from high school during the Voyager flybys of Jupiter and Saturn to see the new pictures on the afternoon PBS coverage of the voyages. It's hard to remember how amazing those pictures were at the time when we were used to grainy telescope images; the pictures of Jupiter where so wildly colorful and unbelievably detailed that you just gasped at them.
posted by octothorpe at 5:36 AM on January 19, 2011 [4 favorites]

ryanrs, how exactly could we collect the Voyager spacecraft? It might be theoretically possible but it's way beyond our current capabilities.

I don't think so. Note, it would be *expensive*, but not impossible, and certainly not beyond our capabilites.

We need the ability to launch a spacecraft into a solar hyperbolic escape orbit. Check -- we did that with New Horizons. Now, New Horizons isn't going as fast as Voyager 1, but that was for mission reason. By using a slightly larger launcher -- like a Delta IV Heavy or Airane 5, and using more than one gravitational assist (say, an Earth-Venus-Jupiter) we could easily get the velocity we need.

Cargo? Spacecraft control systems, a motor, and fuel. When you rendezvous, you then make the first burn, to put the combined craft into a very elliptical solar orbit. Then you wait. When you get close, you perform the second burn to put the craft into a more reasonable orbit near earth, then finally, a third to put the craft into earth orbit.

Then, send a shuttle up and grab it.

There are tricky bits. Actually capturing the spacecraft is tricky, it gets easier if you're willing to accept more damage to Voyager, and getting the thrust aligned to center of mass of the combined spacecraft is a bit ticklish as well -- you'd certainly need an engine on gimbals to be able to vector thrust to avoid spin. Neither, however, is a mission stopper.

Nothing here is impossible -- or even that hard. But it won't be done, because there's no reason to spend anywhere near this much money, given that you're talking two launches, minimum -- and you might want three.
posted by eriko at 5:43 AM on January 19, 2011 [1 favorite]

Although you all realise that as soon a Voyager gets past a certain point, our alien overseers will deem us too advanced, and destroy us. The Mayans knew this.

I read this as "The Wayans" and I was very confused.
posted by empath at 5:46 AM on January 19, 2011 [8 favorites]

I read this as "The Wayans" and I was very confused.

Give it up for the Fly-by Girls!
posted by bondcliff at 6:00 AM on January 19, 2011 [5 favorites]

So long and thanks for all the photons!
posted by tommasz at 6:15 AM on January 19, 2011

My related ask-me from 2006 -- 120+ years before any other current manmade object is more distant from the sun than Voyager 1.

Oh, hey, this is also the 5th anniversary of the New Horizons launch, the mission that prompted me to ask that question...
posted by jepler at 6:19 AM on January 19, 2011

We could fairly easily catch and pass the spacecraft at this point, what with 30 years of technological advancements in ion drives and whatnot. It's absolutely critical that we do so.

Really, do you want those golden records to be our first physical message to the stars? Records have been obsolete for more than two decades. I doubt the aliens will even be able to track down a turntable in 75,611 AD. They're going to receive these things and think we're a primitive culture unworthy of a visit.

We really need to get an iPhone 4 out ahead of those useless old things. At the very least to warn our future overlords that a *really* embarrassing piece of old technology is on its way.
posted by pjaust at 6:24 AM on January 19, 2011 [3 favorites]

They're going to receive these things and think we're a primitive culture unworthy of a visit.

Unless they're audiophiles.
posted by Blazecock Pileon at 6:27 AM on January 19, 2011 [3 favorites]

To: Starfleet Command (in the year 2272 CE)
From: Lootie777 (in the year 1979 CE)
Re: Gigantic space cloud trying to destroy Earth

Please note that the gigantic space cloud trying to destroy Earth is an old NASA space craft that is looking for its creator.

V'Ger = Voyager

PS - Tell Captain Kirk I said hello!
posted by lootie777 at 6:28 AM on January 19, 2011 [1 favorite]

I think it's time for a song
posted by The Whelk at 6:28 AM on January 19, 2011

You know what would be awesome? A Voyager plushie. Forget teddy bears.
posted by Burhanistan at 6:34 AM on January 19, 2011

"They'll run toward Voyager's smouldering remains and they'll dance and shout and burn their hands and we'll get another go at civilisation."

Or, a trillion years from now on a distant planet, there will be a primitive ape-like creature who is just seconds away from inventing the wheel and voyager will come streaking through their atmosphere and smash him right in the head.
posted by puny human at 6:36 AM on January 19, 2011 [3 favorites]

I love this story. Seems like we should send more of these out every ten years or so as the technology gets better.
posted by freakazoid at 6:45 AM on January 19, 2011

The good news is that it won't take much atmosphere to completely incinerate the very small Voyager upon reentry.
posted by Burhanistan at 6:45 AM on January 19, 2011

I doubt the aliens will even be able to track down a turntable

A cartridge and playback instructions are included with the record. Alien nerd Saturday project!
posted by gac at 6:58 AM on January 19, 2011 [1 favorite]

I really think this Voyage experiment needs to be thought over in some more detail before it gets out of hand. Let's not rush into anything here.
posted by Senator at 7:07 AM on January 19, 2011

The last thing we need is aliens getting smug about how they still listen to Voyager on vinyl.
posted by shakespeherian at 7:12 AM on January 19, 2011 [8 favorites]

Don't worry - it'll be back.

To kill us.
posted by Muddler at 7:43 AM on January 19, 2011

Voyager 2 twitter feed if you want to keep up to date with the Voyager missions.
posted by rmd1023 at 7:43 AM on January 19, 2011

I wonder though, through all those billion miles of infinite space, if Voyager will ever discover a world that is even remotely as amazing as the Human Planet?
posted by puny human at 7:57 AM on January 19, 2011

...the twin explorers, now 33 years into their mission, continue to explore new territory as far as 11 billion miles from Earth.

I wouldn't have guessed it was that far away. Wow.
posted by marxchivist at 7:59 AM on January 19, 2011

Fascinating.
posted by CosmicRayCharles at 8:01 AM on January 19, 2011 [1 favorite]

Somewhere there is a nerd who gets paid to work for NASA writing a twitter feed pretending to be Voyage 2.

We could catch Voyager 1 if we managed to turn jealousy into a fuel source.
posted by fullerine at 8:01 AM on January 19, 2011

streaking through their atmosphere and smash him right in the head. his stupid monkey-face

FTFY. I think you're forgetting why we like to put stuff in space.
posted by thsmchnekllsfascists at 8:08 AM on January 19, 2011

I hate Voyager, because it reminds me that we're trapped.

Or, more to the point, that I'm trapped.
posted by aramaic at 8:37 AM on January 19, 2011

Free your mind.
posted by Burhanistan at 8:44 AM on January 19, 2011

See also Living On Earth's episode Forged in the Stars. Warning: Sentimentality. May induce tears.
posted by whuppy at 8:45 AM on January 19, 2011 [1 favorite]

Really, do you want those golden records to be our first physical message to the stars? Records have been obsolete for more than two decades. I doubt the aliens will even be able to track down a turntable in 75,611 AD. They're going to receive these things and think we're a primitive culture unworthy of a visit.

Or worse: they'll think we're hipsters.
posted by brundlefly at 9:37 AM on January 19, 2011 [6 favorites]

Really, do you want those golden records to be our first physical message to the stars? Records have been obsolete for more than two decades. I doubt the aliens will even be able to track down a turntable in 75,611 AD. They're going to receive these things and think we're a primitive culture unworthy of a visit.

75,611 AD: Aliens salvage a CD from a human space probe.
75,612 AD: Aliens reverse-engineer the Red Book standard.
75,620 AD: Alien civilization gets sued into bankruptcy by Phillips.

Of course, alien civilizations are more likely to catch analog Shortwave AM, SSB, or FM than a probe. Still the beauty of analog audio printed onto physical media or translated into radio is that you minimize the number of Rosetta Stones needed to decode it.
posted by KirkJobSluder at 10:25 AM on January 19, 2011

"Note: I don't understand gravitational slingshots in any great detail, but if they can speed stuff up on the way out, they ought to be able to slow stuff down on the way back. Presumably some careful planning will be necessary."

You can't slow down using gravity once something is already beyond the escape velocity of the other object(s) in the equation. Instead, we'd most likely use aerobraking, where the vehicle would skim the upper atmospheres of one or more planets on the way home to burn off velocity.

And indeed that takes careful planning! If you don't want to incinerate your payload. :)

Alternately we could use the solar wind itself to slow down by hanging out a giant solar sail, kind of like parachuting back into the inner system. This sounds safer, but we're still in mostly theoretical stages of that technology.
posted by zoogleplex at 11:12 AM on January 19, 2011

I suppose our big sun is just a tiny point of light among millions(billions? trillions?) of stars from Voyager's POV.
posted by hot_monster at 11:22 AM on January 19, 2011

Actually capturing the spacecraft is tricky, it gets easier if you're willing to accept more damage to Voyager, and getting the thrust aligned to center of mass of the combined spacecraft is a bit ticklish as well

And then once the combined craft returns, you have to maintain the pretense that you're "The Kirk."
posted by Gelatin at 11:36 AM on January 19, 2011

"Sometimes," Professor Quirrell said in a voice so quiet it almost wasn't there, "when this flawed world seems unusually hateful, I wonder whether there might be some other place, far away, where I should have been. I cannot seem to imagine what that place might be, and if I can't even imagine it then how can I believe it exists? And yet the universe is so very, very wide, and perhaps it might exist anyway? But the stars are so very, very far away. It would take a long, long time to get there, even if I knew the way. And I wonder what I would dream about, if I slept for a long, long time..."
posted by d1rge at 11:51 AM on January 19, 2011

Voyager is essentially drifting out of our solar system.
I don't know very much about physics. How does this work?
posted by sunnichka at 12:14 PM on January 19, 2011

This thread so much reminds me of The Big Bang Theory (tv show, not astronomical postulate.)
posted by binturong at 12:26 PM on January 19, 2011

My dad was in his 50s and I was barely in my teens when we worked on the V1 tracking system. The idea that you could toss a tin can the size of VW bug up from Texas or Florida and arrive at outer planets to take closeups color pix was only surpassed by the reality of it made possible by my dad and his colleagues. These were geeks of the highest order pulling off miracles while barely breaking a sweat. They weren't working 80 hours a week to sling some PHP and keep a rack of servers up, you know, around 99% of the time. Their shit was perfect and he was home for dinner every fucking night at 5:30 on the dot.

My dad died in June last year. Goodbye to Voyager, you're cool and all -- but I'd prefer to retrieve my dad if that's at all possible.
posted by victors at 1:48 PM on January 19, 2011 [17 favorites]

I don't know very much about physics. How does this work?

In terms of the physics of Voyager I, in two gravity assist encounters with Jupiter and Saturn it was accelerated above stellar escape velocity. It's moving so fast that it will never come back to the sun. It will keep on flying through the galaxy until it gets picked up by another star or hits a solid object.

More accurately Voyager has reached the limits of the heliosphere. The sun spits out charged particles (mostly electrons, hydrogen, and helium) that stream out away from the sun until it encounters primordial galactic gas. "Gas" is a bit of an overstatement, as both the solar wind and interstellar medium are fairly close to empty. Loosely, it's the equivalent of leaving the Earth's atmosphere, a fuzzy boundary where Voyager is hitting more interstellar hydrogen than solar wind.

This likely isn't the outer limits of the solar system. The Oort cloud is probably further out with its uncounted and currently undetectable comets and dwarf planets. But the heliosphere is a notable boundary between here and, well, the galaxy at large, and not fully understood either in theory or with observations.
posted by KirkJobSluder at 3:30 PM on January 19, 2011

I don't know very much about physics. How does this work?

Just in case you really suck at physics and KirkJobSluder didn't answer exactly what you had in mind: The probe continues to move out of the solar system because there is nothing out there to reduce its speed. Here on Earth, flying things slow down because they collide with trillions of the molecules in our atmosphere. Outer space is empty, so the probe just flies on and on.
posted by ymgve at 3:50 PM on January 19, 2011

We should be building a few good Von Neumann probes that have sciency-type capabilities and can report back.
posted by exlotuseater at 5:16 PM on January 19, 2011

We should be building a few good Von Neumann probes that have sciency-type capabilities and can report back.

Daktaklakpak! 5576 squared!
posted by The Whelk at 5:33 PM on January 19, 2011

I'm curious though. If one of the current probes did have a one-in-a-million gravitational encounter with a dwarf planet or cometary body, could we detect the tiny deflection that would result?
posted by KirkJobSluder at 9:35 PM on January 19, 2011

I suppose our big sun is just a tiny point of light among millions(billions? trillions?) of stars from Voyager's POV.

Nah. Despite all this talk of Voyager leaving the solar system, it's barely stepped off the porch. The nearest star to the Sun is Proxima Centauri, about 4.2 light years away. Voyager is traveling at about 0.0057 light years per century. Were it traveling in the direction of Centauri, Voyager would hit the half-way point in 37,000 years.
posted by ryanrs at 3:50 AM on January 20, 2011 [2 favorites]

KJS: yeah, probably. We would see the signal from the probe deviate from it's current known/predicted path across the sky - it's not flying straight away from earth, it's in a hyperbolic trajectory. Having that path bent a bit by a massive body would become noticeable over time.

I'm not sure if V1 has any maneuvering ability left, so it's possible that a sufficient course deviation could turn the antenna out of line with earth... In which case we'd lose the signal and possibly never regain it.
posted by zoogleplex at 11:00 AM on January 20, 2011

... In which case we'd lose the signal and possibly never regain it.

I vaguely remember reading somewhere that it would lose power around 15 years from now and cease communications?
posted by doublehappy at 4:07 PM on January 20, 2011

Yeah eventually the radioisotope thermoelectric generators's output will drop so low they won't be able to power the transmitter anymore, and we will lose touch with the probe for good.
posted by zoogleplex at 8:27 AM on January 21, 2011

> and we will lose touch with the probe for good.

You shut up!
posted by Burhanistan at 8:28 AM on January 21, 2011

Hey I'm not happy about it, it's just the way it is.

Of course, if you can build a radar/lidar that can get an accurate skin-paint on a 2-meter object that's 20 billion-plus kilometers away, we can keep tabs on it indefinitely.

(And some guys with a lot of gold on their hat brims, as well as some other guys with dark suits and sunglasses, will want to speak with you at some length)
posted by zoogleplex at 9:33 AM on January 21, 2011

Just in case you really suck at physics
Yah, I don't know what I was confused about now that I think about it.
posted by sunnichka at 11:38 AM on January 22, 2011