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Voyager Probes Give Us ET's View

samzenpus posted more than 2 years ago | from the a-different-look dept.

Space 166

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."

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For Science, of course... (5, Funny)

Anonymous Coward | more than 2 years ago | (#38235132)

Pictures of young, hot, stars?! Count me in!

Re:For Science, of course... (0)

Anonymous Coward | more than 2 years ago | (#38235196)

...available in different sizes and colors!

Re:For Science, of course... (2)

Framboise (521772) | more than 2 years ago | (#38235336)

These stars are known to be strong in X.

Re:For Science, of course... (5, Funny)

Anonymous Coward | more than 2 years ago | (#38236256)

As with most hot young stars, they do tend to cool quickly and their waistline expands as they run out of good, hot material. Eventually they can either have a big blowup or become small, not so hot, older stars when they begin using different materials.

Damn. That sounded better in my head but the metaphor got a bit muddled. But, think stars, hydrogen, red giants, helium, novas, etc...

Re:For Science, of course... (1)

Anonymous Coward | more than 2 years ago | (#38236458)

Just remember....Pics or it didn't happen!

Re:For Science, of course... (2)

phatsonic (2499966) | more than 2 years ago | (#38237000)

All stars pictured here are at least 18 years or older.

Re:For Science, of course... (2)

Jason Levine (196982) | more than 2 years ago | (#38237054)

You just have to be careful. Looking at photos of young, hot stars under 180 million years old can get you in trouble.

So Cool... (5, Insightful)

steevven1 (1045978) | more than 2 years ago | (#38235138)

Voyager has to be the coolest space probe ever. It's been operating for 34 years straight and is LEAVING OUR GALAXY, still receiving commands from Earth and still transmitting data back. If that's not marvelous, I don't know what is. Anyone interested should read: http://en.wikipedia.org/wiki/Voyager_1 [wikipedia.org]

Re:So Cool... (3, Insightful)

steevven1 (1045978) | more than 2 years ago | (#38235146)

Correction: solar system, not galaxy. D'oh!

Re:So Cool... (2)

deroby (568773) | more than 2 years ago | (#38235340)

Patience my friend, one day it might actually leave our Galaxy =)

Re:So Cool... (5, Informative)

agentgonzo (1026204) | more than 2 years ago | (#38235682)

Unfortunately not. Milky way's escape velocity is approx 525km/s (wikipedia) and voyager and our solar system are moving at approx 18km/s (Monty Python Song [youtube.com] ). Unless it happens to get flung out of the galaxy by the impending collision with Andromeda in 3-5 billion years it's not going to be leaving the Milky way anytime soon. It'll just float around in the vicinity of the solar system and go around the Milky way.

Re:So Cool... (3)

deroby (568773) | more than 2 years ago | (#38235790)

Ah, I was not aware of that. My bad.
I simply assumed it would take a (ridiculous) amount of time but hadn't considered the required escape velocity of the Milky Way, nor the fact that the probe is just coasting...

Damn, you DO learn something on /. now and then, I'll have to adapt my signature some day =)

Re:So Cool... (2)

Mojo66 (1131579) | more than 2 years ago | (#38236760)

Not true. While its current velocity is too low to escape our galaxy, this can change quickly (in terms of the cosmic time scale) should the probe have a close encounter with a planet or star. This is known as swing-by and was actually used to accelarate the Voyager probes out of the solar system.

Re:So Cool... (1)

tgd (2822) | more than 2 years ago | (#38236952)

I would assume one (and by one, I mean not me!) could calculate the distance it would have to pass away from a typical stellar center of gravity, and figure out if it could actually get a 20x increase in speed without its approach to that center of gravity being within the star.

That'd tell you if it was possible short of passing by something exotic like a neutron star. (And presumably one could calculate how close it would have to pass to even something that dense to get that kind of acceleration, and if the structure of the probe could handle the tidal stress or if it would be torn apart.)

And if you determined there was actually stellar objects that had the sufficient gravity, and sufficient density to accelerate the probe without it hitting the object, you could probably calculate the odds of an encounter with that object resulting in the probe getting that kind of speed, and calculate the number of those objects around and figure out if it really is possible.

I would assume a great many slow accelerations could do it, but every close encounter you need reduces the odds of it not hitting something.

Re:So Cool... (2)

Mojo66 (1131579) | more than 2 years ago | (#38237058)

I agree that the odds for an encounter that would propel the probe to galactic exit velocity or more, are very low. However, the time and space scales we're talking about are so big that agentgonzo's seemingly conclusive statement shouldn't be left uncommented.

Re:So Cool... (0, Troll)

master_p (608214) | more than 2 years ago | (#38235238)

> Score:4, Insightful
> is LEAVING OUR GALAXY

Today is the day Slashdot died :-(.

Re:So Cool... (0)

canix (1176421) | more than 2 years ago | (#38235338)

And you posted that half an hour after he corrected himself ....

Re:So Cool... (5, Interesting)

QuoteMstr (55051) | more than 2 years ago | (#38235354)

The Voyager computers are awesome [nasa.gov] too. How many other 18-bit word [nasa.gov] systems are actively maintained [space.com] today?

I'd love to see the source code, though I'm sure it's terribly boring.

Re:So Cool... (1)

robot256 (1635039) | more than 2 years ago | (#38236266)

It's only boring if you can't read octal...

Re:So Cool... (5, Funny)

Anonymous Coward | more than 2 years ago | (#38235734)

Meanwhile my smartphone will be lucky to survive 34 months, and is only able to receive commands from Earth if I hold it out of an upstairs window...

Out of interest, are there many computers down here on the planet that have been operating constantly for 34 years?

Re:So Cool... (1)

Anonymous Coward | more than 2 years ago | (#38235832)

More than you would think. I have personally seen 50's Univac and 60's IBM systems running - that makes almost 60 years of operations.

Re:So Cool... (5, Funny)

dtmos (447842) | more than 2 years ago | (#38235916)

I have personally seen 50's Univac and 60's IBM systems running

Yes, but when? I, too, have personally seen 50's Univac and 60's IBM systems running.

However, it was in the 50's and 60's.

Re:So Cool... (5, Funny)

flyingfsck (986395) | more than 2 years ago | (#38236002)

Cool, so you must also be in your 60s or 70s and still running...

Re:So Cool... (4, Funny)

dtmos (447842) | more than 2 years ago | (#38236496)

Yes, and before you ask, I, too, have been receiving inquiries from museums.

Re:So Cool... (0)

Anonymous Coward | more than 2 years ago | (#38236200)

I have a 80486 20Mhz computer that has been running constantly at my house since 1995. It is running my alarm system at my house. It has been only down when there has been power failures, which hasn't been many in 16 years in Atlanta Georgia USA.

Nathan

Re:So Cool... (0)

Anonymous Coward | more than 2 years ago | (#38236334)

My Commodore 64 from 1984 still works quite well. It's not on as often as it used to be, but it's still fully functional. I was told recently of a museum in Germany which is planning to revive an Electrologica X8 from 1965. The oldest machine I've personally seen in continuous active use is an SGI Iris from the late 80's. Its current uninterrupted uptime is over 5 years. I own some legacy SGI gear myself and that stuff is built like a brick and weighs a ton. They definitely don't make 'em like that anymore.

Re:So Cool... (0)

Anonymous Coward | more than 2 years ago | (#38236342)

There are PDP geeks that brag about continuous uptime without reboot in that time scale. I don't know what the records are but those systems are surely on the list.

http://en.wikipedia.org/wiki/Uptime

A quick search points to times in the mere 6-8 year time frame. But they don't have nu-cu-lar plants. And are surrounded by annoying uncontrollable humans.

JJ

Embedded systems, industry, infrastructure (1)

DragonHawk (21256) | more than 2 years ago | (#38236890)

Out of interest, are there many computers down here on the planet that have been operating constantly for 34 years?

I'm sure there are embedded and industrial control systems that have been running that long, if only though sheer dumb luck. It would need reliable power, but there's a lot of that around. The computers that run security alarm systems come to mind. Most of them will have had something happen by now, but I bet someone's gotten lucky. Same for industrial control systems which have battery backup and run a continuous process.

Telecom would be another. The older digital telco switches are basically big computers. They're highly redundant and as simple as possible, and practically never go down. I'd bet money there are some with uptimes like that.

But the main reason I feel confident for saying so is that there are so many of those sorts of systems. With a large enough population, even rare events become common.

The Voyager craft are somewhat unique in that there are only two of them . (And they're not exactly reachable for sustaining maintenance.)

Re:So Cool... (1)

phatsonic (2499966) | more than 2 years ago | (#38237134)

Yes. My brain.
And it's leaving the solar system too. More often than my doctors like it to.

Re:So Cool... (1)

macson_g (1551397) | more than 2 years ago | (#38236012)

She is cool indeed. The further she gets from the Sun the coolest she gets. Unfortunately, she's going to be dead cold soon.

30 years later... (2)

guruevi (827432) | more than 2 years ago | (#38235180)

You never know when such research will pay off. The US and EU is scrapping programs now while China, India and a few others try to get into space, you can bet that a lot of cool research will be coming from that side of the globe in the next 30 years.

Imagine if we could launch a probe now with what we have available. We could cheaply launch 10's of much faster probes with incrementally better sensors for the price of the voyager program (~$3B in today's dollars).

Re:30 years later... (4, Insightful)

Brett Buck (811747) | more than 2 years ago | (#38235200)

We could cheaply launch 10's of much faster probes with incrementally better sensors for the price of the voyager program (~$3B in today's dollars).

          I am not sure why you say that. The costs of space technology haven't changed much at all relative to the rate of inflation, and there haven't been any important breakthroughs in launchers. The only thing consequentially different is computer capability, but a faster/more complex computer would just as likely be a liability as a bonus. Software design techniques, if anything, have gone rapidly backwards for this sort of application since the late 70s/early 80s.

Re:30 years later... (2)

steevven1 (1045978) | more than 2 years ago | (#38235220)

I'd say that the hardware for collecting data has substantially improved with time too (imaging sensors, etc.). Not to mention storage capacity, and I'm sure there is plenty of other stuff I can't think of right now, even if launching technology hasn't changed much. There could definitely be huge benefits.

Re:30 years later... (2)

Brett Buck (811747) | more than 2 years ago | (#38235246)

Those same advantages have tended to reduce reliability and robustness, particularly robustness to radiation damage.

Re:30 years later... (5, Interesting)

amRadioHed (463061) | more than 2 years ago | (#38235580)

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?

Re:30 years later... (0)

Anonymous Coward | more than 2 years ago | (#38235642)

Need a source of electricity which can power the engines until they run out of reaction mass. Not sure of the RTGs used on those space craft are strong enough and if the engines would tolerate the decay of power output.

Re:30 years later... (1)

Electricity Likes Me (1098643) | more than 2 years ago | (#38236008)

You could put a satellite in close orbit to the sun for the express purpose of beaming power towards the space probe, either with MASERs or LASERs.

The real question is whether there's enough gas density in outer space for a hypothetical space probe to also collect it's own reaction mass .

And of course whether all this could let us accelerate enough to do the really cool stuff like insert into Alpha Centauri orbit.

Re:30 years later... (2, Interesting)

Anonymous Coward | more than 2 years ago | (#38236606)

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.

Re:30 years later... (5, Insightful)

Kjella (173770) | more than 2 years ago | (#38235270)

Software design techniques, if anything, have gone rapidly backwards for this sort of application since the late 70s/early 80s.

I'd say the Mars rovers are a good counterexample of that, they're "new" and have been operating for many, many years now. Particularly when it comes to data compression the current probes have a huge leg up on the old ones. That said, yeah computers can't rewrite physics and launching anything into space is still quite expensive and they don't really go faster from it either.

Re:30 years later... (5, Funny)

Anonymous Coward | more than 2 years ago | (#38235422)

If we build the probe from neutrinos we could possibly launch it faster than light. And get the results a few years ago.
If we had known to listen to them, that is.

Re:30 years later... (2)

peragrin (659227) | more than 2 years ago | (#38235906)

nope you want the communication system using neutrino's. that way only the results get sent back.

Of course even if the neutrino experiment is true, it only means a an hour or two shaved off the 16 hours it takes to get the data at the ranges in question.

Re:30 years later... (5, Interesting)

Tastecicles (1153671) | more than 2 years ago | (#38235524)

Oh [nasa.gov] , 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 [intel.com] - a non-hardened computer package these days weighs no more than 3lb [wikipedia.org] , with terrestrial ruggedised coming in at little more [toughbook.eu] . 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.

Re:30 years later... (0)

Anonymous Coward | more than 2 years ago | (#38236222)

Wow +4 interesting an idea to put a laptop in space all rugged up with steel.

oh god.

Re:30 years later... (1)

necro81 (917438) | more than 2 years ago | (#38236258)

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.

All well and good, but how do you power it for a deep-space mission? Ion propulsion systems require 1000W - 10,000W of electrical input. You might be able to manage that at the beginning of the trip with solar panels, but solar incidence falls with the square of distance: at 1.4 AU you are already down to 1/2 power, at Jupiter you are down to just 4% of your original power. You could try using RTGs but, other than the fact that there are none available, even the most abundantly powered RTG craft ever - Cassini - had less than 1 kW of electrical output at launch.

Re:30 years later... (3, Informative)

Tastecicles (1153671) | more than 2 years ago | (#38236516)

ESI is the way (as I said, sans gravity well effects), generation of electrical power is somebody else's problem. As you've pointed out, solar is useless as a source for deep space probes; self contained generation of power is the only option, and right now all we have is RTG. This is what ion engines have used in every practical application so far (examples that spring to mind are SERT I and II, and DS1) and until something better comes along, it'll continue to be a sink for RTGs in deep space exploration. As to your claim that there are no RTGs available: I could build a crude but functional one in about five minutes (if I had a pellet of [insert name of suitable isotope here]), and it's not as if we're short of radioisotopes suited for the task. The problem lies in a particular nation state unilaterally and unjustifiably denying any other from possessing any quantity of refined radioisotopes for any reason other than the manufacture of smoke alarms. That nation state continues to throw RTGs all over the Arctic in the name of science and monitoring the military movements of others without the need to lay thousands of miles of power lines, and there is far more than the Apollo 13 RTG sitting at the bottom of the ocean - the Atlantic passive SOSUS net buoys are all RTG powered (there is very little sunlight three miles underwater).

Re:30 years later... (0)

Anonymous Coward | more than 2 years ago | (#38236984)

Wait, Deep Space 1 and also Smart 1 used solar cells. But otherwise using RTGs is right for this of course.

Re:30 years later... (4, Informative)

Muad'Dave (255648) | more than 2 years ago | (#38236292)

A couple or three pounds of lead and a steel cage to protect against EMI/RFI I think is all that is needed.

At the high gamma energies found in space, lead is no better than aluminum as a gamma shield [wikipedia.org] , and both are pretty anemic. 1 cm of either will attenuate high energy gamma rays by only about 50-70%.

No, biggest non-fuel part is NOT the CPU (1)

wisebabo (638845) | more than 2 years ago | (#38236942)

I'm as big a fan of the smaller, faster, cheaper paradigm as anyone but there is one thing about ALL these space probes that CAN'T be miniaturized.

It's the communications subsystem, most notably the antenna. I'm pretty sure that it can't be miniaturized due to the laws of physics dictating aperture and gain etc. (Unfortunately, I am not an physicist :( Also, ever since the Galileo probe antenna DISASTER (I call getting much less than one-hundredth the bandwidth a disaster) caused by the fact that the antenna didn't unfurl properly, means NASA is very conservative about using lightweight technologies. So unless the probe is designed to return to earth-space, bandwidth requirements will dictate a large (and heavy) antenna. (Still I'm not sure if the weight-bandwidth rule applies to coherent laser/maser communications, I understand that an upcoming mars orbiter will test using a laser link for much higher bandwidth).

That said, the advances in miniaturization (which extends to sensors and complete lab-on-a-chip) are extremely encouraging. Perhaps probes of the future will have a main "mothership" which will provide the communications link to lots of semi-autonomous micro-probes.

Re:30 years later... (4, Interesting)

khallow (566160) | more than 2 years ago | (#38235562)

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).

Re:30 years later... (2)

Talderas (1212466) | more than 2 years ago | (#38236192)

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.

Convert for inflation..
$20k 1980 dollars = $52k current
$20k 1982 dollars = $45k current
$20k 1985 dollars = $40k current
$20k 1987 dollars = $38k current
$20k 1989 dollars = $35k current

So at best, you're talking about around a 70-80% decrease in cost. SpaceX's cost would be about 85-90% lower than the 1980s.

Re:30 years later... (5, Informative)

stephanruby (542433) | more than 2 years ago | (#38235690)

The only thing consequentially different is computer capability, but a faster/more complex computer would just as likely be a liability as a bonus. Software design techniques, if anything, have gone rapidly backwards for this sort of application since the late 70s/early 80s.

Thankfully, some of our/your assumptions about space technology are currently being proven wrong. For instance, take the Nexus One. NASA has been testing it to see if it could make cheaper smaller satellites with it, and its performance in that regard has been completely outstanding.

Granted, it hasn't survived 30 years in space yet, only time will tell on that one.

But it can survive in all kinds of extreme temperatures, all kinds of G forces, and it works perfectly well in a vacuum. And it's so small to begin with, the extra hardware it needs to power it, recharge it, move it, etc, doesn't have to be that big to begin with.

During one of its space test, the Nexus One was even strapped to the tip of a rocket and the rocket accidentally crashed back into the desert leaving a large crater, but the phone only got a cracked screen and was still fully functional otherwise.

And this is probably something that's not unique to that phone, or to Android, in particular. Consumer-grade devices, because they've been designed to survive actual consumers and sometimes even little kids, have come a long way in terms of reliability.

And granted, a Nexus One will still have bugs that would normally be intolerable in the older type of computers designed for space, but it has enough computing power to be reprogrammed remotely and compensate for most bugs that are found after the fact. And since they take much less space and weight, and are much cheaper to launch. You can launch half a dozen for a fraction of the cost it used to launch an older type of satellite, thus building a type of redundancy that we just couldn't afford to have with the older kind.

So if anything needs to improve, it's probably not our technology, but our mindset. We have good technology. That technology may not be perfect, but it should be more than good enough for unmanned space exploration at least. And it's grand time we start using it for that purpose.

Re:30 years later... (2)

tibit (1762298) | more than 2 years ago | (#38236994)

But it can survive in all kinds of extreme temperatures, all kinds of G forces, and it works perfectly well in a vacuum. And it's so small to begin with, the extra hardware it needs to power it, recharge it, move it, etc, doesn't have to be that big to begin.

Sorry, that's engineering fantasy. No, a phone not designed for it will not survive "all kinds of extreme temperatures", "all kinds of G forces", etc. You'd have to test it -- you know, environmental chambers, shakers, etc. Without such tests any assumptions are pure fantasy. We don't know how it works in vacuum, because it hasn't really been in vacuum, only in atmosphere that's survivable to humans with supplemental oxygen. There's plenty of components that I'd expect will experience problems in vacuum simply because there's no reason at all to put ones rated for vacuum operation in a consumer device. Silly things such as plastic encapsulant outgassing can have dire consequences for quite short-term reliability (weeks). Thermal management becomes a big issue because you have to radiate all the heat out of the enclosure with no convection to help you.

I have once seen tests of a fairly unassuming low-key data acquisition device in vacuum at -100C to 100C temperature ranges, and there was a lot of redesign involved to get it to work acceptably with no air present around it. It still could be done by qualifying everyday COTS components that you can get from any distributor like DigiKey (no milspec stuff), but this requires quite good recordkeeping and procedures/software to make sure human mistakes don't slip through.

Re:30 years later... (0)

Anonymous Coward | more than 2 years ago | (#38235804)

India have it easy... they only have to clean up their vimanas, fill up their fuel tanks with mercury and leave Earth whenever they want...

Re:30 years later... (5, Informative)

JasterBobaMereel (1102861) | more than 2 years ago | (#38235478)

Launched today they would not do much .... they relied on a chance alignment of the planets that allowed them to use gravitational slingshots to get there in a reasonable time, tour most of the planets, and leave the solar system ... next time this will happen is around 2150 ...

Re:30 years later... (2)

Kagura (843695) | more than 2 years ago | (#38235600)

You never know when such research will pay off. The US and EU is scrapping programs now while China, India and a few others try to get into space, you can bet that a lot of cool research will be coming from that side of the globe in the next 30 years.

Imagine if we could launch a probe now with what we have available. We could cheaply launch 10's of much faster probes with incrementally better sensors for the price of the voyager program (~$3B in today's dollars).

As a side related note, I have heard nothing about New Horizons' after-rendezvous plans other than a possible second Kuiper belt flyby, but I'll bet you a million bucks that they've over-engineered this probe to later provide the kind of science that 1970s' Voyager is doing for us still today.

Re:30 years later... (2)

necro81 (917438) | more than 2 years ago | (#38236224)

We could cheaply launch 10's of much faster probes with incrementally better sensors for the price of the voyager program (~$3B in today's dollars)

you are off in your reckoning. We could perhaps launch a handful of small craft, but certainly not 10's. And although technology has progressed, the speed with which we can travel in the solar system hasn't changed much.

For comparison, the New Horizons [wikipedia.org] mission to Pluto has an expected lifetime cost of about $650 million - and that is a very modest probe. If it were an Earth-sensing mission (leaving aside the RTGs vs. solar panels), the mission cost would probably be half that - chump change as satellites go. The additional cost comes in part from the need for a more powerful rocket, but also because there is so much added rigor in testing the spacecraft beforehand (all their eggs in one basket, so to speak), and because you need to employ an entire support staff for a decade before you even get there.

Another example is the recently launched Juno [wikipedia.org] mission to Jupiter. That's a ~$1 billion mission (again, lifetime costs from inception through eventual death-plunge into Jupiter). The spacecraft itself is probably more expensive than would otherwise be expected because of all the radiation-hardening it needs (and testing that accompanies that). The spacecraft uses a huge (60 m^2) array of high-efficiency (triple junction GaAs, I would guess) solar panels for power, which may actually be more expensive than the conventional alternative of RTGs.

On the plus side, both of these spacecraft are amazing science platforms and will provide impressive results over their missions. New Horizons has already provided new data regarding Jupiter (flyby in 2007).

Impressive (5, Insightful)

PortaDiFerro (1719902) | more than 2 years ago | (#38235182)

That must be one of the most successful space exploration projects so far, too bad it's running out of juice!

Re:Impressive (5, Interesting)

niktemadur (793971) | more than 2 years ago | (#38235522)

The distance at which the Voyagers are still collecting and transmitting useful data back to Earth, is mind boggling.
Over a light day away! [nasa.gov]

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 [wikipedia.org] 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!

Re:Impressive (0)

Kagura (843695) | more than 2 years ago | (#38235616)

Wow. I know you were going for prose, but this must be an off-day for you. You should have written just the first sentence and link and then submitted the post like that. You would have been modded up to parent's level.

Re:Impressive (3, Informative)

Kjella (173770) | more than 2 years ago | (#38235958)

The distance at which the Voyagers are still collecting and transmitting useful data back to Earth, is mind boggling. Over a light day away!

Uh? 120 AU is only 0.7 light days. And if that's far depends on perspective, it's 0.05% of the way to the closest star. Somehow the Mars rovers have been a lot more visual in saying that yes, we can do interplanetary with their cameras. The Voyager probes are more of a reminder that interstellar is a completely different ballgame. Thirty three years and 18 billion kilometers out yet it's still gotten nowhere in interstellar terms. Though it's fun to see them still operational and still doing science...

Re:Impressive (0)

Anonymous Coward | more than 2 years ago | (#38235930)

Indeed! Go V-ger! Someday, Kirk will find you. Don't f-up our timeline by running out of power now, you haven't become sentient yet.

Question About Voyager(s)... (4, Interesting)

steevven1 (1045978) | more than 2 years ago | (#38235206)

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.

Re:Question About Voyager(s)... (0)

Anonymous Coward | more than 2 years ago | (#38235234)

Obvious troll is obvious

Re:Question About Voyager(s)... (0)

Anonymous Coward | more than 2 years ago | (#38235384)

Hey, don't think foreign nations won't be interested in keeping their.. I mean, taking our space oil.

Re:Question About Voyager(s)... (3, Interesting)

Kagura (843695) | more than 2 years ago | (#38235626)

Obvious troll is obvious

No... you're just dumb. I've always wondered this, too. Not just about Voyagers, but all space exploration probes. No states have an interest in sending these false commands, but I wonder if it is possible or practical.

Edit: I just reread the grandparent's reply, and the way he posed the question makes him out to be an idiot. I won't suggest modding him up, but his question is at least valid. Anyone know about how secure communications with space probes is accomplished? :)

Re:Question About Voyager(s)... (5, Interesting)

agentgonzo (1026204) | more than 2 years ago | (#38235710)

It's an interesting question, but regardless of whether anyone can theoretically crack the authorisation to upload commands to the Voyagers, I believe that it's only NASA's deep space network that can actually send the signals that far to be received by the probes.

Re:Question About Voyager(s)... (1)

perryizgr8 (1370173) | more than 2 years ago | (#38235748)

i think nasa's radio stuff still leaves any other space agency's shit far behind. china and esa simply don't have the tech to send signals that far away.

Re:Question About Voyager(s)... (3, Insightful)

Anonymous Coward | more than 2 years ago | (#38235272)

> What's to keep enemies of the United States from sending it bad instructions, or from collecting all data it sends back to us?

The fact that they are so far away that talking or listening to the Voyagers _REQUIRES_ a POINTABLE satellite dish 70 fucking meters in diameter. Only three that big exist in the world, and guess who owns them?

http://voyager.jpl.nasa.gov/news/profiles_dsn.html

Re:Question About Voyager(s)... (0)

Anonymous Coward | more than 2 years ago | (#38235302)

guess who owns them?

guess who pwns them?

Re:Question About Voyager(s)... (1)

datapharmer (1099455) | more than 2 years ago | (#38235796)

they run scada... so yes, pwned. ;-)

Re:Question About Voyager(s)... (4, Interesting)

Framboise (521772) | more than 2 years ago | (#38235390)

In the linked article I didn't find that "only three" such antennae exist. The deep space network made of three big antennae is able to follow and control Voyager without interruption, but other isolated and big antennae exist and might be used to perturb the spacecrafts, probably with slight modifications.

Germany has a 100 m radiotelescope (Effelsberg), UK a 76m one (Jodrell Bank), Australia a 64 m one (Parkes), and China builds a 300m equivalent one, FAST, to be ready in 2013 (http://en.wikipedia.org/wiki/Five_hundred_meter_Aperture_Spherical_Telescope).

   

Re:Question About Voyager(s)... (4, Interesting)

Tastecicles (1153671) | more than 2 years ago | (#38235640)

It's not just single large antennae that can be used to detect signals from Voyager.

The VLA uses technology developed in Britain (actually, a quirk of physics) to use several small antennae to simulate one large antenna. You can do the same, using similar frequencies to those used for the Voyager downlink (2.3GHz), a few lengths of coaxial cable, some one and a half inch nails, and four feet of marine ply.

1. Set two nails in the ply a set distance apart, call this distance D. You'll need this.
2. Connect each nail to its own demodulator (AKA receiver), then connect the receivers to a phase correlator.
3. Set the phase correlator to cycle the sinD differential between the two signals.
4. Take the output to a computer for decoding.

It is possible to do the phase correlation on the computer, or simply use the computer to record the signals from each receiver (forgetting about the phase correlator altogether) and combine them later. If you're dealing with streaming data (like you would be if using WiFi) you'll need a phase correlator* or set sinD as close to zero as you can get it (by setting the nails in the case of WiFi at multiples of 1.21"/30.734mm apart - as far apart as you can get them).

*There is a way around this, but it also requires precise angle measurement. If you know which direction your signal is coming from, you can point your interferometer toward it (the elements set exactly perpendicular to the signal source so they receive the signal in precise phase alignment). It helps if the interferometer is mounted on a common axis as this does away with the need for a phase correlator.

An improvement on this extremely simple design is the use of "cantennas" or other narrow-field antenna, which develops a narrow but high gain cone for the receiving antenna, making life a bit easier for finding the transmitter. If you want to get ambitious, the VLA uses 27 antennas, a 21+21+21km 3-way rail baseline, and several supercomputers.

Re:Question About Voyager(s)... (1)

Ogi_UnixNut (916982) | more than 2 years ago | (#38235954)

I'd love to know more about this! Always wanted to know how they connect multiple receivers together. Not just for low frequency em, but things like light etc... Do you know of any DIY projects that did something like this? Would make some nice Friday reading over here :)

I wonder if anyone wrote any OSS software to do the above. It would be cool!

Re:Question About Voyager(s)... (2)

Tastecicles (1153671) | more than 2 years ago | (#38236358)

easiest way to play with (recorded) signals is to use stereo audio waveforms in something like Audacity: take each channel (representing the signal recorded from each receiver) and subtract one from other (destructive interferometry), add them together (constructive interferometry), phase shift (same as signal correlation) then subtract or add... there are all sorts of ways to get all sorts of effects from three filters which come with the software: add, subtract, phase, and you can hear the results practically instantly. Great for demonstrations once you get your head around why it's doing what it's doing (which is very basic in terms of mathematics).

Once you do get your head around it, the rest is gravy - it's all just waves in space, the only practical difference is the nature of the receiver.

Re:Question About Voyager(s)... (2)

Muad'Dave (255648) | more than 2 years ago | (#38236360)

http://en.wikipedia.org/wiki/Beamforming [wikipedia.org]
http://en.wikipedia.org/wiki/Phased_array [wikipedia.org]
On a slightly different scale: http://www.km5kg.com/array.htm [km5kg.com]

If you're interested in modern radio techniques, I suggest getting a decent book on Digital Signal Processing [wikipedia.org] and software-defined radio. The things that can be accomplished with software are amazing!

Um, no. (3, Interesting)

dtmos (447842) | more than 2 years ago | (#38236080)

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.

Re:Um, no. (1)

Tastecicles (1153671) | more than 2 years ago | (#38236276)

I don't have a 70m dish to hand. I do, however, have an array of 9 Cantennas, which I use on a motorised axis to wardrive from home. I've picked wifi signals from several miles away - wifi uses weak signals which usually have an effective range of less than one eighth of a mile and even less when you factor in the bleed from surrounding devices such as Bluetooth and microwave ovens. It's not the size of the dish, it's the number you have, and the more you have the higher the SNR (providing you have the element spacings, hence the standing wave ratio, right). A larger antenna only increases the incident signal voltage, which can damage the receiver equipment (particularly CMOS gear) - which is why you should balance the antenna with the wavelength you're working at (eg, an 11m antenna for 11m radio). An increased ISV does not mean increased SNR, in fact because the antenna is designed to work over a range of frequencies a filter needs to be in place to isolate the floor noise and amplify the useful stuff. In a simple analogue radio this is achieved with a tuning capacitor and an amplifier circuit - the receiver is useless without these components. If you have a 2 kilometre wire wrapped around a ferrite rod, connected through a germanium crystal and a piezoelectric speaker, through to ground, you have a signal-powered AM receiver specific to 492KHz and no other frequency (use an adjustable coil from 615-2000m for a simple antenna tuner which can receive anywhere on the commercial AM spectrum but with a very low SNR - it'll be useable but very hissy). Try using the same antenna on a commercially built HF CMOS receiver and I guarantee you one thing: you will blow the tuner.

Re:Um, no. (2)

dtmos (447842) | more than 2 years ago | (#38236472)

By moving from one to nine antennas, you'll get an effective area improvement of at most 9, or 8 dB, but most of the improvement you're seeing is, in fact, the phenomenon you describe -- you're creating a phased array that rejects signals from undesired transmitters in the ISM band, in order to receive the desired signal.

The problem in receiving the Voyager probes, however, is not this problem. The Voyager problem is that one doesn't have enough incoming signal to manipulate at all -- when received by even a 10m dish it's so far buried in the noise that it is undetectable at practical integration times. The solution, as you state, is to "increase the incident signal voltage" into the receiver, and the only way to do this is to increase the effective area of the antenna.

Re:Um, no. (0)

Anonymous Coward | more than 2 years ago | (#38237296)

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.

But, isn't angular resolution equivalent to antenna gain? Sharper the main beam, higher the gain. Also, you receive less noise from adjacent angles.

Re:Question About Voyager(s)... (5, Interesting)

rimcrazy (146022) | more than 2 years ago | (#38236416)

Not that anyone is probably interested but I worked in the group that made the radios that are in Voyager. I just missed working on those specific models but I worked on the next generation following those use on Voyager. Working there (Motorola GED) I worked close with NASA and was in the loop on all the programs, past and current that we were working on with NASA. What is really remarkable here is both Voyager probes have "failed" receivers on them. There was a problem with the capacitors that were used for the input loop bandwidth filters. These failed in such a manner as to cause the acquisition loop bandwidth to be a very narrow band instead of the intended wide band. NASA was able to recover using these radios by basically making an empirical model of each of the spacecraft. They did this when the spacecraft were relatively close to the earth and they could blast them with wideband signals to ensure acquisition. What they did with the model was to identify exactly how the on board xtals in the radio aged or varied with power and temp and then threw in compensation for age and doppler. With all of this data then then had a model that told them on such and such a date, the correct xmit frequency to use to put the carrier in the middle of the narrow band filter is X. They would dial it in, send it out and everything still worked. Actually a very clever fix for what would have been a disaster.

Re:Question About Voyager(s)... (1)

adri (173121) | more than 2 years ago | (#38237260)

.. why isn't this in wikipedia somewhere? Was this ever published?

Re:Question About Voyager(s)... (0)

Anonymous Coward | more than 2 years ago | (#38235922)

20 meter disk receives Voyager signals.
http://slashdot.org/index2.pl?fhfilter=bochum+voyager

Re:Question About Voyager(s)... (4, Interesting)

ETEQ (519425) | more than 2 years ago | (#38235294)

I don't think it's encrypted, but I think the methods of encoding the transmissions are incredibly arcane and the formats for the data are nothing even approaching standard (standards for such things didn't exist back then). Probably more important is that the only radio receivers in the entire world that are capable of detecting its signal are run by NASA...

Re:Question About Voyager(s)... (2)

Zoxed (676559) | more than 2 years ago | (#38235868)

I work in ground based space systems, and can confirm it is tough enough to write the code for a modern satellite *with the documentation* :-0

Re:Question About Voyager(s)... (2)

vikingpower (768921) | more than 2 years ago | (#38235434)

Your is the strangest of mindsets. "Enemies of the United States" ? "Collecting all data it sends back to us" ? This is about science, dude. Cool down. The moment is not close for the US to militarily occupy outer space. ( It will have gone bankrupt before that time ).

Re:Question About Voyager(s)... (1)

necro81 (917438) | more than 2 years ago | (#38236344)

at this point the limiting factor would be the fact that you need fantastically sensitive radio equipment to communicate with Voyager. At this point, only NASA's Deep Space Network can manage it. The Voyager transmitters are only about 20 W, and by the time it reaches Earth 10-12 hours later is down to about 10^-18 W (about -150 dB). You need large radio dish antennae and uniquely sensitive equipment to be able to receive that. On the transmit side, I've seen the number 20 kW bandied about, again with very large antennae that can direct that very precisely. Radio astronomers have sensitive dishes, but not many facilities also have transmit capabilities.

If someone wanted to built a competing Deep Space Network, they wouldn't be able to do keep it a secret. The infrastructure (i.e., the dish) would be conspicuous, as would the transmissions. Do something nefarious with it (like trying to hijack voyager) would probably result in a cruise missile up your ass. And even if you could hijack Voyager, why would you?

Re:Question About Voyager(s)... (1)

Tim C (15259) | more than 2 years ago | (#38236444)

I don't know about the protection from rogue commands (it may simply be impractical or impossible for any other agency to transmit to them now), but as for the data collection question - who cares if someone else does receive the data? It in no way prevents NASA from also receiving it.

Re:Question About Voyager(s)... (1)

neonKow (1239288) | more than 2 years ago | (#38236664)

I feel like the reason this hasn't been done is that it is just a dick move with no benefit for the people who do it. Nothing prevents other countries from collecting the data, but it's not like any other nation believes that sending rogue instructions to them is in any way beneficial to them.

It would basically be just vandalism. Vandalism on the farthest man-made devices from the Earth.

I am astonished... (0)

Anonymous Coward | more than 2 years ago | (#38235278)

... about how this article may sound to someone with no interest in space exploration. *young hot stars*, *streaming milky way* ... stripping all non sci terms from the article (which human mind may easily do) may prove it quite misleading. :P

ok (0)

Anonymous Coward | more than 2 years ago | (#38235480)

I hope this is not yet another hoax claim that steers too much commotion amongst eager ET fans. P. End [cleanngone.co.uk]

40 times as far away? (3, Interesting)

agentgonzo (1026204) | more than 2 years ago | (#38235722)

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?

Re:40 times as far away? (0)

Anonymous Coward | more than 2 years ago | (#38235928)

Yeah but, now it is possibly over double the distance away!
That's double the news! Neeewwwws~

Re:40 times as far away? (3, Insightful)

Shadowmist (57488) | more than 2 years ago | (#38235952)

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?

Presumably because it's only recently that they discovered techniques to make these observations with the remaining equipment on board. Voyager is now making measurements it was never designed to. Keep in mind that the engineers who built these ships did not expect them to last as long as they did, nor that we would still be able to get useful signal strength from them at this point. Also remember that with the twin factors of half life decay and thermocouple degradation, they're only getting about half the power from the RTG's that they used to, so some equipment has had to have been permanently turned off.

Re:40 times as far away? (2)

Kjella (173770) | more than 2 years ago | (#38235996)

Not just the summary, but the article is probably horribly wrong. The new measurements are almost certainly related to the probes approaching the edge of the heliosphere [wikipedia.org] , but the journalist didn't have a clue and confused it with the distance to Pluto - which is about 40 AU.

I feel better for knowing they are out there (2)

donkeyb (965462) | more than 2 years ago | (#38235836)

A surprisingly large part of me feels good that those amazing spacecraft are so far away, nearing the depths of interstellar space and will continue on for as near as makes no difference to forever. An even larger part of me regrets that I won't be around to see the day when they make contact with another civilisation.

Re:I feel better for knowing they are out there (2)

Tastecicles (1153671) | more than 2 years ago | (#38235858)

In other news, a partial image was just received from Voyager 2 which has DHS worried [wikimedia.org] . Contact with the probe has not been reestablished.

ET's View (0)

Anonymous Coward | more than 2 years ago | (#38235860)

Reading the headline, I guessed that the story was about what an alien SETI might be able to distinguish about us from all our TV & Radio noise.

Does anyone know how powerful the Voyager comms link is compared with 'normal' broadcasting?

Re:ET's View (3, Insightful)

dtmos (447842) | more than 2 years ago | (#38236330)

This [nasa.gov] seems to be a pretty good description of the Voyager telecom system. Based on this, the X-band transmitter provides 18 watts to the high-gain antenna, which has a gain of 48 dB, for an effective radiated power of just over 18 * 10^(48/10) = 1.1 megawatts. (At least at launch; I assume the output power will have fallen somewhat over the intervening decades, as the RTG output falls and RF components age.)

This sounds like a healthy amount of power, and it is, but keep in mind that antenna gain comes easy at X-band (8 GHz), and such ERP levels are common in terrestrial point-to-point microwave links. Also keep in mind that the half-power beamwidth of the high-gain antenna is only 0.5 degrees, so any alien not in that narrow beam would hear substantially nothing.

Also, to answer your direct question, the frequencies and beam shapes are different, and one has to consider the shielding effects of the ionosphere vs. frequency, but just to compare (US regulations, YMMV): AM broadcast stations (~1 MHz) are usually limited to 10 kW with more-or-less 0 dB gain antennas, for an ERP of 10 kW; but UHF TV stations (~500 MHz) may have an ERP of up to 5 MW.

Of course, there are a zillion broadcast stations, all transmitting non-coherently (some would say incoherently), but only two Voyagers, so that would have to be taken into account, too.

Precaution (0)

Anonymous Coward | more than 2 years ago | (#38236880)

While they're still out there, we would do well to ensure the survival of whales.

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