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Voyager Probes Give Us ET's View
astroengine writes "For the first time, scientists have been able to measure a type of radiation streaming out from the Milky Way that in other galaxies has been linked to the birthplaces of young, hot stars. There was no way to make our own galaxy's measurement of the radiation, known as Lyman-alpha, until the Voyager probes were about 40 times as far away from the sun as Earth — any closer and the solar system's own emissions drowned out the fainter glow from the galaxy."
It receives commands from Earth, and it's 34 years old. What's to keep enemies of the United States from sending it bad instructions, or from collecting all data it sends back to us? I realize that Voyager isn't of any military importance, but I guess this is more of a hypothetical question. Does it use some type of encryption? Is that encryption still unbreakable today? The keys haven't been compromised after all this time? Just curious.
The Voyager computers are awesome too. How many other 18-bit word systems are actively maintained today?
I'd love to see the source code, though I'm sure it's terribly boring.
The distance at which the Voyagers are still collecting and transmitting useful data back to Earth, is mind boggling.
Over a light day away!
Back in 1989, when Voyager 2 flew past Neptune, the JPL command center was probably dismantled and refitted for the next glamor project, while the long final phase of the Voyager mission was relocated to a much tinier space, probably the basement, with a couple of old-school, hardcore Voyager geeks down there, living on Doritos, pizza and Usenet, a rickety AC rattling and slowly dripping water over a puddle, unfixed for months because the Maintenance Department is constantly needed up at Voyager's old stomping ground, kept immaculate for the Galileo probe people, or Cassini, or the Mars Rovers, whatever the Flavor Of The Lustrum was / is.
Nice and quiet down there among the rusted ceiling pipes and aged Crays, though. They didn't bother nobody, nobody bothered them. Beer could be smuggled to work and no one would notice, everybody upstairs would be swooning over Neil DeGrasse Tyson filming a segment on Pluto and the Horizons mission. Only time anybody saw the strange Voyager geeks, was when they went up to the ground floor vending machines, as the supply guy always forgot to restock the one in the JPL basement, forgot there was one in the basement.
Little did anybody know (except for these guys) that the Voyagers were like an aging boxer with one good fight left in them, very low bitrate coupled with an ultra-weak signal perhaps, but with still one final, grand potential payoff - a peek at the outside, which may end up being the longest lasting legacy of all.
Look at it now bitches, it's on the other side of the heliopause!
Lil' Thindime, lilting a lacrimose lament, krashes the kwaint konfines of Kokonino Kounty
Oh, I don't know... electrostatic ion propulsion is already proven to be more efficient than ordinary chemical propulsion (once you get out of the gravity well).
As long as you have fuel, you'll keep accelerating, albeit at a very small rate. It might take ten or twenty years, but I reckon that if an ESI probe was launched tomorrow it'd overtake Voyager and still have propellant to go faster.
The bonus is with computer technology; that while it's gotten thousands of times faster in practically every respect, it's also gotten a lot smaller - a non-hardened computer package these days weighs no more than 3lb, with terrestrial ruggedised coming in at little more. The advantage of this is obvious: with the single biggest non-fuel component of the spacecraft now the size of a paperback, you have far less mass to push.
Of course, you don't need a screen or a keyboard in deep space, so cut the weight in half and you've got something a smidge lighter than the several hundred pounds of GE custom machine that went up with Voyager, that has its own battery, that pulls about ten Watts rather than over a hundred, that uses solid state storage, and in most cases can automagically govern its own power load (this would be why the later Shuttle missions used self-contained laptops rather than a room full of mathematicians and radio that meant data moved at the speed of speech) - I've metered my netbook off the line and found it runs on between 3-35W, averaging 11, including the screen on minimum brightness.
That said, you do need to protect the computer against hard radiation. That will obviously push the weight up, but not so much as to make it unmanageable. A couple or three pounds of lead and a steel cage to protect against EMI/RFI I think is all that is needed. The major part of the probe is then going to be propulsion systems and fuel, and the science package.
Operation Guillotine is in effect.
The costs of space technology haven't changed much at all relative to the rate of inflation
When you get away from government projects and missions you find an interesting thing. They've gone down in absolute dollars. It's not rare to find private analogues which cost an order of magnitude or more less than the government counterpart.
For example, prior to the early 80s, there was no commercial space flight of any sort. When it first opened up with offerings from Arianespace, Boeing, and Lockheed, prices were on the order of $20k per kg (to low Earth orbit or "LEO"), a bit better than the Space Shuttle. Now there's perhaps a dozen private space launch providers, some offering flight costs well under $10k per kg. So we've gone from $20k per kg in 80s dollars to under $10k per kg in today's dollars. And if SpaceX delivers, we'll be hitting $5k per kg (in today's dollars), perhaps less. The Russians have a good chance of meeting that price point as well.
It'll never be a Moore's Law thing, but we are seeing a remarkable long term decline in launch costs over a few decades. So no breakthrough in launch technology (with the exception of the creation of commercial space flight in the 80s and the possible exception of SpaceX now) yet we still manage to drop prices considerably even before adjusting for inflation.
Second, there are great economies of scale in launching tens of probes. For example, R&D is divided up over a large number of probes. There are learning curve effects from building tens of probes and part costs will go down. Now maybe building a Voyager-level vehicle wouldn't be as cheap as the original poster claimed, but I bet $3 billion can buy a lot of interstellar probes, just the same. Especially, if one cuts out the slick tools that Voyager used for its planet flybys, but which weren't used for the interstellar portion of the mission (such as the imaging cameras).
They wouldn't be using state of the art chips, but even the old radiation hardened chips needed for space travel would be an big improvement over 30 year old technology.
Probably the biggest improvement would be in propulsion. Isn't this the exact sort of mission the new ion propulsion systems would be perfect for?
We hope your rules and wisdom choke you / Now we are one in everlasting peace
Last I heard, the voyagers are about 100-110 AUs from the sun. Is the summary incorrect or do you only need to be 40 AUs from the sun to make these measurments? In which case, why is it news now and not in the 80s/90s when they reached this distance?
You're confusing antenna angular resolution with antenna effective area. The problem with reception of the Voyager probes isn't being able to discern them among other relevant signals. The problem is that the signals are so weak that they need an antenna with large area just to collect enough energy per bit to reliably overcome noise generated in the receiving system. Until you do this, you can't get a signal strong enough for your correlator to work on -- all you'll get out of the correlator is noise, because that's all that's going in to the correlator from your receivers.
Ergo, the 70m dishes.
My understanding is that the noise from radiation only became a significant problem with newer chips running at lower voltages. The radiation shielding is a better solution for better systems, but ironically the old technology wasn't good enough to have this problem. Older logic systems (eg TTL but possibly not in this case) were designed for noisier, less stable circuits in general and radiation in space just happened to be just the sort of interferance it could tolerate.