Voyager 1 still transmits data... what is that like at NASA?

[rogerbox]

I am fascinated with Voyager 1, because a piece of equipment that can operate that long in such an environment beyond designed specifications is just awesome. According to wikipedia and other websites I have read, it still transmits data to earth:
http://en.wikipedia.org/wiki/Voyager_1

What I would like to know is:

1) Is this data useful, or is it so primitive and returning data that we already know about with more modern instruments?

2) At NASA what resources are used to receive this data? Is it someone's fulltime job, or did someone write a script to collect the data on a PC that people look at occasionally etc?

[aceplace57]

July 2012 article. Somebody is still monitoring the data.

"The latest data from Voyager 1 indicate that we are clearly in a new region where things are changing quickly," says Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena. This is very exciting. We are approaching the solar system's final frontier."

The “frontier” he’s referring to is the edge of the heliosphere, a great magnetic bubble that surrounds the sun and planets. The heliosphere is the sun’s own magnetic field inflated to gargantuan proportions by the solar wind. Inside lies the solar system—“home.” Outside lies interstellar space, where no spacecraft has gone before.

When Voyager 1 actually exits the heliosphere, researchers expect to see other changes as well. For one thing, energetic particles from the sun will become scarce as the spacecraft leaves the heliosphere behind. Also, the magnetic field around Voyager 1 will change direction from that of the sun’s magnetic field to that of the new and unexplored magnetism of interstellar space.

http://www.nasa.gov/mission_pages/vo...-frontier.html

[Senegoid]

Voyager 1 was launched in 1977, thus built with 1977 technology. The on-board technology can never be updated, but the earth-side receiving and processing equipment has been been upgraded over the years.

I read about this stuff once. Rather than do the research again myself, I'll mention a few vague details. It's all there on-line for the interested to find.

The transmitter is primitive by modern standards. It transmits at a baud rate that would be laughable today. It was deliberately slow even by 1977 standards, to make the transmissions more reliable. Each bit is transmitted for a long period of time (some fraction of a second), the the receiver judges each bit to be 0 or 1 according to whichever state it sees each bit being in "most of the time". This is necessary since the signal is so faint and "noisy". The pictures are smallish, low-resolution, and black-and-white. At its present distance, out at the edge of the solar system, the transmission time is about 16 hours. The signal wattage as received on earth is some small fraction of the wattage of a modern digital wristwatch. (Meaning, some small number of billionths as strong, or some such outrageous statistic.)

Earth-side, the signals are received by several antenna networks. I think each receiving station (of which there are several around the world) consists of a whole field full of antennas, and with each technology upgrade, they cover more acreage with ever-more-sensitive antennas.

Lately (or recently?), NASA is starting to get data from the edge of the solar system. There's a special name for that region -- Heliosheath, according to Wikipedia.

For further research, start with the Voyager 1 wikipedia, the source I used for a few of the above details, and take it from there. I see the OP has already read and cited that Wiki -- But there's plenty more out there!

[rogerbox]

Another question, for a story:

Say an alien species or humans in the distant future DO encounter Voyager 1, where is the Golden disc? Is it inside the craft? Do you need tools to open it? What is it like to get to the disc? A quick googling doesn't reveal this to me.

[whc.03grady]

The disc is just pasted on the side of the vehicle:
http://en.wikipedia.org/wiki/File:Re..._Voyager_1.jpg

[greenslime1951]

Originally Posted by whc.03grady

The disc is just pasted on the side of the vehicle:
http://en.wikipedia.org/wiki/File:Re..._Voyager_1.jpg

And in a whimsical act of practical jokery, the CD was surreptitiously swapped out for a recording of "Meat Loaf's Greatest Hits" just before launch.

[Alessan]

CD?

Hah. Kids.

[Senegoid]

Originally Posted by rogerbox

Say an alien species or humans in the distant future DO encounter Voyager 1, where is the Golden disc? Is it inside the craft? Do you need tools to open it? What is it like to get to the disc? A quick googling doesn't reveal this to me.

Just a hopeful-WAG here, but I'm guessing it requires hammer, chisel, blasting caps, and opposable thumbs (by deliberate design). This is to encourage aliens reasonably like ourselves to come visit, but discourage aliens with lots of tentacles.

Originally Posted by greenslime1951

And in a whimsical act of practical jokery, the CD was surreptitiously swapped out for a recording of "Meat Loaf's Greatest Hits" just before launch.

Originally Posted by Alessan

CD?

Hah. Kids.

He's confusing V'ger with the ending scenes of "Escape From Manhattan".

[Alka Seltzer]

As aceplace57 said, that data is still being monitored. It's useful data too, as we have nothing else out that far. It's being used to find one of the boundaries of the solar system, the heliopause. Once it crosses that, Voyager 1 will be in interstellar space.

In 1990, ten years after it's last planetary encounter, Voyager took the Pale Blue Dot picture, which is one one of my favourite astronomical images. Visually, it's not very striking, but that blue pixel to the right is Earth.

[ftg]

Even if the instruments themselves weren't recording data, just the transmitter itself is useful. Noticing subtle changes in track over time is interesting. For a while there an anomaly was detected with Pioneer spacecraft that was thought to indicate our understanding of gravity was off a bit, but that's been resolved by normal means. But there is still a chance that we might detect something gravitationally in the future. So tracking it is still worthwhile.

[J-P L]

So, is NASA actually sending command signals to Voyager, or is it only on the receiving end at this time.

[Ca3799]

It is (well, they are, since there are two Voyagers) still being monitored.

I recently heard an interview on RadioLab called "Is there and Edge to the Heavens" with Ann Druyan , who picked the sounds on the Voyager record, and another scientist, Marev Opher, part of the current Voyager monitoring team. The first half of the RadioLab story is about Isaac Newton. The Ann Druyan part starts at about 11 minutes.

(Here: http://www.radiolab.org/2012/feb/20/edge-heavens/).

Druyan described checking on the Voyager using Google Alerts and described how the Voyager is still been being monitored and still responds.

Initially, because there were long periods of not very interesting news, the monitoring team would get together every time Voyager got near a planet to look at the pictures.

Carl Sagan personally requested they turn the Voyager after it passed Neptune to take that final picture that caught the famous 'Pale Blue Dot' picture that Alka Seltzer linked to above, and then cameras were turned off.

But the other sensors are still operational. The monitoring team still loans the receiving antennas to other people for other uses.

Druyan said they would ping the ship periodically: Control: "Hey, Voyager, whaddaya see". Voyager: "Nothing".

Then one day, about 14 years into the trip, the solar winds dropped from 400-800 kilometer per second to 380 k/s. They thought they had reached the 'edge'.

In 2004, it happened again. The solar wind dropped from 380 k/s to 100 k/s and the particles and the magnetic fields were behaving differently. They thought they were out of the solar system, but now think they are 'in the edge of the bubble'. Apparently, the edge is thick and the Voyagers have traveled in this edge for several years now.

Then another change- the wind stopped completely.

But they think the Voyagers are still not 'out of the edge', or have not yet left our solar system, but that they will soon.

They think they are in the 'edge of the edge'- what they are calling a 'stagnation layer'.

I think the Voyagers have traveled about 11 billion miles now. It takes 15 or 16 hours for the radio signals to travel to us.

[treis]

How long before the signals drop to the level of background radiation?

[Robot Arm]

Originally Posted by rogerbox

Say an alien species or humans in the distant future DO encounter Voyager 1, where is the Golden disc? Is it inside the craft? Do you need tools to open it? What is it like to get to the disc? A quick googling doesn't reveal this to me.

I just hope the instructions tell them to hold the record by the edges.

Originally Posted by greenslime1951

And in a whimsical act of practical jokery, the CD was surreptitiously swapped out for a recording of "Meat Loaf's Greatest Hits" just before launch.

"Send more Chuck Berry."

[Elendil's Heir]

Originally Posted by Alka Seltzer

...In 1990, ten years after it's last planetary encounter, Voyager took the Pale Blue Dot picture, which is one one of my favourite astronomical images. Visually, it's not very striking, but that blue pixel to the right is Earth.

Be sure to read what Sagan wrote. Sheer brilliance: http://en.wikipedia.org/wiki/Pale_bl...tions_by_Sagan

[BMalion]

Originally Posted by Elendil's Heir

Be sure to read what Sagan wrote. Sheer brilliance: http://en.wikipedia.org/wiki/Pale_bl...tions_by_Sagan

That is beautiful.

The 1970's still rocks!

[Shamozzle]

Sagan rocks:

"If we long to believe that the stars rise and set for us, that we are the reason there is a Universe, does science do us a disservice in deflating our conceits?"

[Chimera]

Originally Posted by Shamozzle

"If we long to believe that the stars rise and set for us, that we are the reason there is a Universe, does science do us a disservice in deflating our conceits?"

Then you can meander over to the pit, or our news media, and be told of people in this country who honestly DO believe that we should outlaw science that deflates our conceits.

[standingwave]

Originally Posted by treis

How long before the signals drop to the level of background radiation?

That's dependent to a large degree simply upon the size of the receiving antenna. I've read that a with a dish the size of Arecibo, original broadcasts of 'I Love Lucy' originals could be received out to a few light-years. With a larger dish, perhaps an orbiting array, signals could be picked up at further distances.

[Mr. Greenjeans]

There seems to be debate recently about whether or not Voyager has left the solar system.

Still, it's 18.5 billion kilometers away. Far out.

[Saint Cad]

Any chance that JPL will power up the camera to take a quick picture of the Sun at that distance?

[Keeve]

But do zombies still transmit data that far out?

[chargerrich]

Originally Posted by Elendil's Heir

Be sure to read what Sagan wrote. Sheer brilliance: http://en.wikipedia.org/wiki/Pale_bl...tions_by_Sagan

That quote and the associated picture of our "pale blue dot" is quite simply the most amazing and profound image and text ever written. Anyone with even a modicum of interest in science and our planet should devour everything Carl Sagan ever wrote or mused.

Decades later, reading that still moves me. The man embodied the perfect balance of genius and delivery. He died too soon and our world is less without him.

[Peremensoe]

Originally Posted by Keeve

But do zombies still transmit data that far out?

Not a zombie thread, given the subject.

[panache45]

Originally Posted by greenslime1951

And in a whimsical act of practical jokery, the CD was surreptitiously swapped out for a recording of "Meat Loaf's Greatest Hits" just before launch.

Or this. It's guaranteed to repel any hostile aliens. On the other hand, if they're totally different from us, they may actually like it.

[Learjeff]

I work at Nasa. It's my job. I expect the next bit to arrive sometime this evening, so don't bug me: I'm busy.

[Francis Vaughan]

An important point to make about very faint signals. Faint signals don't stop being detectable when they are weaker than the background noise. This is a direct result of Shannon's law on communication in a noisy channel. What you do have is a relationship between information rate and signal to noise ratio. Even if the signal is weaker than the noise, there is a non-zero information transfer rate. It just gets slower and slower as the signal level drops.

[Senegoid]

Originally Posted by Francis Vaughan

What you do have is a relationship between information rate and signal to noise ratio. Even if the signal is weaker than the noise, there is a non-zero information transfer rate. It just gets slower and slower as the signal level drops.

Does NASA have two-way communication with Voyager I? Can they send out commands to it, like they send commands to the not-so-distant Mars scouts? And it there a command to tell it to slow down the transmission rate?

Learjeff? Can you take some time to fight our ignorance, in between bits?

As I noted several posts above, the point of slowing down the transmission rate is that each bit has to be transmitted continuously for a long time (meaning some substantial fraction of a second), so the receiver can get a lengthy sampling of each bit, the better to get good statistics for it. So what bit rate is it sending these day?

[Peter Morris]

Originally Posted by Mr. Greenjeans

There seems to be debate recently about whether or not Voyager has left the solar system.

Obligatory XKCD link.

[cochrane]

Originally Posted by greenslime1951

And in a whimsical act of practical jokery, the CD was surreptitiously swapped out for a recording of "Meat Loaf's Greatest Hits" just before launch.

Heh. Or even more likely, "Stoney and Meatloaf."

[JBDivmstr]

Originally Posted by Elendil's Heir

Be sure to read what Sagan wrote. Sheer brilliance: http://en.wikipedia.org/wiki/Pale_bl...tions_by_Sagan

I was unaware of this particular bit of history, which makes me ever so glad that I took the time to read this thread!

I've watched a number of programs with Carl Sagan and I must agree, the man was very eloquent.

This thread alone, makes the cost of a membership and the time that I spend perusing the contents of The Straight Dope, worth every penny.

[shijinn]

Originally Posted by Peter Morris

Obligatory XKCD link.

that's another reflection of just how big the place is..

[Learjeff]

Originally Posted by Senegoid

Learjeff? Can you take some time to fight our ignorance, in between bits?

Sorry, I was just joking.

[Learjeff]

Originally Posted by panache45

Or this. It's guaranteed to repel any hostile aliens. On the other hand, if they're totally different from us, they may actually like it.

Thanks! I just learned of the Dunning-Kruger effect.

I think I'll rename my soul band to the Dunning Kruger Soul Band. (The Dunning Kruger Band is already taken, darnit.)

[Kevbo]

Originally Posted by Senegoid

V At its present distance, out at the edge of the solar system, the transmission time is about 16 hours.

Note that this does not mean it takes 16 hours to transmit a picture. (I'm pretty sure it takes far longer at this point, actually). It means that it takes 16 hours for the radio signal, which is traveling at the speed of light, to get from the spacecraft to the earth. Back in 1990 when the last pale blue dot photos were taken, the spacecraft was "only" about 5 light hours from earth.

[Chimera]

[Stupid]

Well gosh, can't they just fly out to it and upgrade the equipment?

[/stupid]

[Elendil's Heir]

Originally Posted by shijinn

that's another reflection of just how big the place is..

"Space is big. Really big. I mean, you may think it's a long way down to the chemists, but that's nothing compared to space." - Douglas Adams

[control-z]

I say after it passed Pluto it was out of the solar system.

[eltro102]

a bit unrelated but the mars rover opportunity is still roving around on Mars, 9 years after it landed (even though its original mission was only 92 days!). It managed this because it has solar panels, periodically cleaned by the wind (unlike curiosity, which will only last 4-5 years because of its nuclear source)

[anson2995]

Originally Posted by Senegoid

Does NASA have two-way communication with Voyager I? Can they send out commands to it, like they send commands to the not-so-distant Mars scouts? And it there a command to tell it to slow down the transmission rate?

The answers to many of these questions can be found at the Voyager team's NASA website. And if you still have questions, you can email the team directly.

[Skammer]

Originally Posted by eltro102

It managed this because it has solar panels, periodically cleaned by the wind

Think how long it would have lasted if they'd thought to put windshield wipers on the solar panels.

[hajario]

Originally Posted by eltro102

a bit unrelated but the mars rover opportunity is still roving around on Mars, 9 years after it landed (even though its original mission was only 92 days!). It managed this because it has solar panels, periodically cleaned by the wind (unlike curiosity, which will only last 4-5 years because of its nuclear source)

A former colleague of mine did some of the analysis on that. They weren't sure how sticky the soil would be and the most conservative estimates had dust continuing to pile up on the panels until they couldn't gather anymore light. As it happened, fortunately, there is just a thin layer of dust and the rest blows/shakes off.

[gnoitall]

Originally Posted by control-z

I say after it passed Pluto it was out of the solar system.

Why Pluto? It's not as if it were one of the planets.

Besides, for about 1/12 of its year, Pluto is closer to the Sun than Neptune.

And the Oort Cloud (source of many comets) is part of the Solar System, and that's well beyond the planets OR the heliosphere. The Oort cloud may exend almost an entire light-year around the Sun. From a gravitational perspective (rather than an electromagnetic and particle perspective), the Oort cloud can be considered the edge of the Solar System, but Voyager is still a hell of a long ways from that edge.

[Senegoid]

Originally Posted by Learjeff

Sorry, I was just joking.

So was I.

Originally Posted by anson2995

The answers to many of these questions can be found at the Voyager team's NASA website. And if you still have questions, you can email the team directly.

Yes, the FAQ there does talk about sending commands from Earth to the Voyagers. That's impressive that this works.

[Frumpy Jones]

Originally Posted by gnoitall

Why Pluto? It's not as if it were one of the planets.

insert obligatory Jonathan Coulton song about Pluto here (it's a free download.. That's how cool JoCo is)...

[Frumpy Jones]

Originally Posted by Kevbo (I bolded the point of my reply)

Note that this does not mean it takes 16 hours to transmit a picture. (I'm pretty sure it takes far longer at this point, actually). It means that it takes 16 hours for the radio signal, which is traveling at the speed of light, to get from the spacecraft to the earth. Back in 1990 when the last pale blue dot photos were taken, the spacecraft was "only" about 5 light hours from earth.

Ummmmm, unless there's something I'm missing, and it's quite possible I am, how does a radio wave, which is sound if I remember correctly, travel at the speed of light?

[Northern Piper]

a radio-wave is part of the electromagnetic spectrum and travels at the same rate as light, which is also part of the electromagnetic spectrum.

Here on Earth, we use it to transmit sound, but the sound at the transmitter is converted to radio waves, and then the receiver re-converts the radio-waves back to sound. The original sound does not travel over the radio waves.

[Tangent]

Radio waves are not sound waves. They are electromagnetic waves ("light waves") with relatively long wavelengths.

Wikipedia article on radio waves

[Frumpy Jones]

See how I covered my ass before sounding like an uninformed dolt?

Thanks for the info

[control-z]

I think alien teenagers have captured Voyager 1 and are sending back fake transmissions. They sit around all day listening to the Voyager gold record and smoking space weed.