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Print E-mail del.icio.us 51 comment(s) - last by PrinceGaz.. on Nov 30 at 4:02 PM

The Voyager 2 space probe should be crossing another milestone any day now.

Shortly after Voyager 2's 30th anniversary in space, the probe is set to achieve another milestone in its journey; it is expected to cross the termination shock in late 2007 or early 2008. The termination shock is a spherical area that surrounds the solar system where solar winds slow to subsonic speeds.

Though launched 10 days later, Voyager 2's sister craft, Voyager 1 crossed the termination shock in December of 2004, three years ahead of Voyager 2's projected arrival. The earlier crossing was due to a shorter trajectory out of the solar system.

The prediction comes from physicist Haruichi Washimi at University of California, Riverside. Washimi used a global magneto-hydrodynamic simulation in conjunction with data from Voyager 2 to give the window where the probe will likely cross the boundary. The simulation is a "method that allows precise and quantitative predictions of geometric disturbances caused by solar activities," according to a release at UCR.

"This is the first time the termination-shock position has been forecast in this way. After it crosses this boundary, Voyager 2 will be in the outer heliosphere beyond which lies the interstellar medium and galactic space. Our simulations also show that the spacecraft will cross the termination shock again in the middle of 2008. This will happen because of the back and forth movement of the termination-shock boundary. This means Voyager 2 will experience multiple crossings of the termination shock. These crossings will come to an end after the spacecraft escapes into galactic space," explained Washimi.

Launched August 20th, 1977, Voyager 2 has seen four planets -- Jupiter, Saturn, Uranus and Neptune -- and their moons on its way out of the solar system. The original Voyager missions where slated only to visit Jupiter and Saturn, along with their largest moons. The extraordinary success of the missions convinced NASA to extend Voyager 2's mission and use gravitational boosting to propel it towards Uranus and Neptune.

Though still operational, the natural decay of the plutonium fuel on the craft has forced shutdown of several systems to keep it operational. At launch, the Radioisotope Thermoelectric Generator pumped out 470 watts of power, but by 2001, output was down to a meager 319 watts. Both the Voyager crafts are projected to have enough fuel to continue operations until about 2020.



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Very cool...
By ChristopherO on 11/28/2007 5:26:53 PM , Rating: 2
It's good to see these probes still being useful to science after so many years. I'll occasionally check the Heavens Above site to see their current position, etc.

Given that I'm not a physicist, and I don't keep up on drive technology... Is it possible to build a vastly faster probe than the Voyager series?

I remember something about an ion drive that was tested a few years back. It was the space-based equivalent to getting propulsion from a leaky faucet. I think it bled off a very small stream of ions, but did it with a huge degree of force, so the cumulative impact of months of propulsion was a very significant velocity.

I'd like to see probes out to the Kuiper belt, but I just don't see that as being too feasible since the nuclear fuel needs a significant life span, plus you have to factor in a decade of electronic usage without failure.

We definitely need a faster drive in order to reach the further planets in a reasonable amount of time. Given that, we should be able to get there and undertake higher-quality science.

The Voyager probes might be providing data, but realistically it's just a drop in the bucket compared to what they could previously accomplish. There has been some sensor failure, some have been shut down to power, so at this point there are only a couple instruments, the primary computer, and the heater online.




RE: Very cool...
By ChristopherO on 11/28/2007 5:30:57 PM , Rating: 2
Oh, and kudos on the Ilia photo... That was one awesome movie. Actually my favorite in the series. Khan / First Contact might have been the most exciting, but TMP was definitely the purest in regards to science fiction content. TMP was more 2001 than Star Wars.


RE: Very cool...
By wordsworm on 11/29/2007 4:51:44 AM , Rating: 4
Hogwash. Star Trek IV was the most scientifically pure of them all. If the whales ever stop singing, we're all doomed!


RE: Very cool...
By marvdmartian on 11/29/2007 9:38:14 AM , Rating: 2
Agreed. Props to Levi for the photo (and those of us old enough to remember it's significance).

Oh, and since no one else has mentioned it, this thing passed URANUS!!! ;)


RE: Very cool...
By masher2 (blog) on 11/28/2007 5:35:46 PM , Rating: 3
> "Is it possible to build a vastly faster probe than the Voyager series?"

Sure; it just requires nuclear power. However, since the 1963 nuclear test ban treaty, the US has lost all interest in nuclear propulsion for spacecraft.


RE: Very cool...
By creathir on 11/28/2007 5:51:04 PM , Rating: 5
Which this baffles me. With all the environmental concerns of carbon based fuels, you would think nuclear power would be investigated further. I suppose I am a crazy one, but I am of the ilk that beleives we could perfect the process so much that it would be someday possible to use small amounts for fuel cell type of power systems, even for automobiles.

I guess its just pie in the sky ideas though...

- Creathir


RE: Very cool...
By BlackBanna on 11/28/2007 10:13:30 PM , Rating: 2
NASA and the EU have been working on Ion drives.

http://nmp.nasa.gov/ds1/tech/ionpropfaq.html

similar principal of a nuclear fueled one.


RE: Very cool...
By Shadowself on 11/28/2007 6:06:51 PM , Rating: 1
Look up the JIMO (Jupiter Icy Moons Orbiter) among other missions. NASA is still actively exploring these possibilities. They are just not actively funding the build of any of those reactors.

The 1963 treaty has nothing to do with a loss of interest in nuclear propulsion. It's cost.

Nuclear propulsion will happen -- just not soon.


RE: Very cool...
By Chernobyl68 on 11/28/2007 6:12:39 PM , Rating: 2
well, that and environmental cost. The tree huggers always point to "what happens if it blows up on launch"


RE: Very cool...
By Zurtex on 11/28/07, Rating: 0
RE: Very cool...
By AsicsNow on 11/28/2007 9:46:21 PM , Rating: 2
The difference in safety however is that Nuclear powered space ships could leave the atmosphere slowly with a constantly supplied thrust, which is much safer than the extreme amount of energy expended in a very short time frame by chemical rockets. So basically the you're risk is much lower of an accident happening, which should help balance out the more problematic aftermath of a nuclear powered spaceship exploding on liftoff. (it'd also be TONS safer for returning into the atmosphere because they don't have to worry about the risky ass aerobraking procedures since they could simply reverse thrust over the ocean and come down in a much more controlled manner)


RE: Very cool...
By howtochooseausername on 11/28/2007 11:06:10 PM , Rating: 2
You need to accelerate above 9.81m/s2 to leave the atmosphere. Exactly which nuclear powered engine produces that kind of thrust? Or are you just assuming that such an engine exists?


RE: Very cool...
By CyborgTMT on 11/29/2007 2:21:15 AM , Rating: 2
You are assuming vertical take off - I don't see why conventional means could take a craft into the upper atmosphere like a plane then kick in the nuclear engine to boost into space.


RE: Very cool...
By howtochooseausername on 11/29/2007 10:40:32 AM , Rating: 2
The upper atmosphere still isn't high enough (~40mi, someone correct me on that). The craft would still need to generate a lot of thrust at that height.

F=Gm1m2/r^2. I forget the value of G, but r is the distance between the two masses m1, and m2.
So you know that F = 1/2 m2*dv where dv is the change in velocity, and m2 is the same as the previous mass.

Anyways, no, you'd have to be fairly high up, past the mesosphere before the thrust produced by current Nuclear engines would be able to overcome Earth's gravity.


RE: Very cool...
By Cerberus29 on 11/29/2007 10:59:56 AM , Rating: 2
G is 6.67 x 10^-11.

Just finished doing gravitational fields in Physics. :D.


RE: Very cool...
By Chernobyl68 on 11/28/2007 6:11:40 PM , Rating: 3
The voyager's are moving very fast becaue of the multiple slingshots they've gotten from the planets they've visited. They're pretty much just moving on inertia now.


RE: Very cool...
By regpfj on 11/28/2007 7:13:03 PM , Rating: 3
Check out this kick-ass idea for 1/10 c travel from ARPA, propelled by our friend the atom.

http://www.damninteresting.com/?p=679


RE: Very cool...
By howtochooseausername on 11/28/2007 11:14:48 PM , Rating: 2
I think in 71 NASA stopped further investigation of Nuclear thrust. Prior to that the AEC assisted in funding some of the research that NASA did.

It was not the nuclear test ban treaty that killed it, but people's fear of nuclear weapons. Considering that nuclear missiles were targeted at the US and minutes away from launch, a justifiable fear. Now that we aren't threatened by MAD, it might be worth re-investigating Nuclear propulsion.


RE: Very cool...
By Treckin on 11/28/2007 11:45:42 PM , Rating: 3
This is totally false...
If you want to find out why, do your own damn research, im sick of citing websites and wasting my time researching things I already know to show people...

Up until only 1985 they had a fully functional nuclear engine in the New Mexico desert.

There are also even better ways to achieve velocities faster than an inertial gravity engine, such as Ion drive, solar wind, hydrogen collection etc. Some are obviously better candidates for different missions than others.


RE: Very cool...
By ChristopherO on 11/29/2007 1:11:12 AM , Rating: 2
This is rather frustrating. From what I understand, the benefit of nuclear propulsion isn't as great as one would think. Basically it seems the nuclear reaction takes place of the oxidizer, which leaves you a liquid fuel (hydrogen). More or less, you get twice the propulsion from a given weight of fuel. It's not "revolutionary" since we're not talking about exponential gains in efficiency, but a 100% improvement isn't anything to sneeze at. Of course that's an over simplification.

I've been watching Mars Rising on the Science Channel and they've been talking that almost all the long-term plans for returning to the Moon and Mars feature a nuclear drive. Anyway, the show is obviously simplifying things, but it is interesting to see what NASA and the ESA have on the drawing board.

Mars Rising has been quite good. DirecTV has it on VOD, you need an HR20 HD DVR and it has to be hooked up to broadband... I've downloaded 4 of the episodes so far.