When Voyager and Pioneer are 1 lightyear away |
When Voyager and Pioneer are 1 lightyear away |
Apr 1 2006, 02:17 AM
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#1
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Junior Member Group: Members Posts: 40 Joined: 20-March 06 Member No.: 720 |
How long will it take before they reaches the 1 lightyear limit? And how is the Sun looks like at that distance? Is the sun shining bright there or is it very dark then. How difficult will it be to make eventual contact with them?
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Apr 1 2006, 06:10 AM
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#2
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Senior Member Group: Members Posts: 2492 Joined: 15-January 05 From: center Italy Member No.: 150 |
How long will it take before they reaches the 1 lightyear limit? And how is the Sun looks like at that distance? Is the sun shining bright there or is it very dark then. How difficult will it be to make eventual contact with them? Voyager is the fastest one, covering more than half billion Km each year... deceleration is almost negligible, so it will take something like 18000 years to reach 1 light year distance from the Sun! At this distance, Sun appear like a -3 magnitude star, so still the most luminous object in the sky (slightly less bright than Venus at its maximum). Any contact would be impossible because, apart distance, onboard RTG generators will be completely exhaust. -------------------- I always think before posting! - Marco -
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Guest_Richard Trigaux_* |
Apr 1 2006, 06:10 AM
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#3
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Guests |
How long will it take before they reaches the 1 lightyear limit? And how is the Sun looks like at that distance? Is the sun shining bright there or is it very dark then. How difficult will it be to make eventual contact with them? The ships will reach this distance in hundred of thousand years. At that time, even if the equipment is still working, their radioisotopic energy source will be extinct for long. Already today it is wondered if they can still receive a command and reply to it (last test failed). The Pu238 has 80 years half life, which makes than in a thousand years only it will be extinct. |
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Apr 1 2006, 11:12 AM
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#4
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Member Group: Members Posts: 356 Joined: 12-March 05 Member No.: 190 |
...of course the RTG power output lifetime is far less constrained by the termal output of the radioisotope than it is by the dopant migration and degradation of thermoelectric semiconductor junctions which actually produce the electricity, and thus they will be producing far less than 50% of the initial power at the 80 year Pu239 half life point.
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Apr 1 2006, 01:40 PM
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#5
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Junior Member Group: Members Posts: 40 Joined: 20-March 06 Member No.: 720 |
Voyager is the fastest one, covering more than half billion Km each year... deceleration is almost negligible, so it will take something like 18000 years to reach 1 light year distance from the Sun! At this distance, Sun appear like a -3 magnitude star, so still the most luminous object in the sky (slightly less bright than Venus at its maximum). Any contact would be impossible because, apart distance, onboard RTG generators will be completely exhaust. It will be really dark then at 1 lightyear distance with only a bright star (the Sun) in the sky. I think it looks like the same when Jupiter is shining at its brightest here on earth ,is that true? |
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Guest_PhilCo126_* |
Apr 1 2006, 04:09 PM
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#6
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Don't know if this was already posted:
http://www.southgatearc.org/news/april2006/voyager1.htm |
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Apr 1 2006, 06:25 PM
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#7
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Senior Member Group: Members Posts: 2492 Joined: 15-January 05 From: center Italy Member No.: 150 |
Don't know if this was already posted: http://www.southgatearc.org/news/april2006/voyager1.htm Cannot believe, an "amateur" 20m antenna detected Voyager signal from almost 100 au! ...are we sure isn't another 1st april joke? -------------------- I always think before posting! - Marco -
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Apr 1 2006, 07:01 PM
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#8
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Senior Member Group: Members Posts: 2488 Joined: 17-April 05 From: Glasgow, Scotland, UK Member No.: 239 |
Cannot believe, an "amateur" 20m antenna detected Voyager signal from almost 100 au! ...are we sure isn't another 1st april joke? 'Signal', perhaps - but not data! Put a bundle of such guys together, though, on five continents... Bob Shaw -------------------- Remember: Time Flies like the wind - but Fruit Flies like bananas!
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Apr 1 2006, 08:07 PM
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#9
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Founder Group: Chairman Posts: 14431 Joined: 8-February 04 Member No.: 1 |
Well - 20m isnt that much less than 34 which is the smaller ( but much more common ) DSN asset - and they DO get Voyager data pulled out of the signal on an almost daily basis.
Granted - the later is about 3x the area Lot's of amaeturs getting in on the amateur DSN scene -it's quite remarkable. Doug |
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Apr 3 2006, 08:30 AM
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#10
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Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
The Pu239 has 80 years half life, which makes than in a thousand years only it will be extinct. Except that the RTGs don't use Pu-239, they most commonly use Pu-238 in the form of plutonium dioxide. IIRC, Pu238 is harder to acquire than Pu239 and that's one of the reasons these things cost so much. But you're right on the half life, it is some 88 years. -------------------- |
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Guest_PhilCo126_* |
Apr 14 2006, 05:00 PM
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#11
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Just read this in Spaceflight magazine (May 2006 page 167 ):
PIONEER 10 lost in Deep Space NASA DSN has failed to contact the venerable spacecraft an it seems that its 'active' mission is now effectively over. ... It is now heading towards a 3.3 light year encounter with the star Ross 248 in 33000 years time. Well I guess the spacecraft lasted 35 years |
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Guest_Richard Trigaux_* |
Apr 14 2006, 07:43 PM
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#12
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Guests |
Except that the RTGs don't use Pu-239, they most commonly use Pu-238 in the form of plutonium dioxide. IIRC, Pu238 is harder to acquire than Pu239 and that's one of the reasons these things cost so much. But you're right on the half life, it is some 88 years. AAAArrrrgghhh stupid mistake. I meaned Pu 238 of course, so I corrected in the initial post. Pu 239 has a 24000 years half life, but it would not provide enogh power for a RTG. Tons of it would be required, but it would be "a bit" unstable... |
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Apr 14 2006, 09:35 PM
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#13
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Senior Member Group: Members Posts: 2919 Joined: 14-February 06 From: Very close to the Pyrénées Mountains (France) Member No.: 682 |
Just read this in Spaceflight magazine (May 2006 page 167 ): PIONEER 10 lost in Deep Space NASA DSN has failed to contact the venerable spacecraft an it seems that its 'active' mission is now effectively over. ... It is now heading towards a 3.3 light year encounter with the star Ross 248 in 33000 years time. Well I guess the spacecraft lasted 35 years 34 to be precise; launched on march 2nd 1972. Would you believed this : it was the very first day I took a car driving lesson! Anyway, there is one point where we're not consistant : Pioneer 10 will be 3.3 light year from Ross 248, which is 10.3 light year from here (I mean, France ) in 33.000 years, while Voyager is traveling one light year in 18.000 years. Something wrong, eh ? -------------------- |
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Apr 14 2006, 11:35 PM
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#14
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
Just read this in Spaceflight magazine (May 2006 page 167 ): PIONEER 10 lost in Deep Space NASA DSN has failed to contact the venerable spacecraft an it seems that its 'active' mission is now effectively over. ... It is now heading towards a 3.3 light year encounter with the star Ross 248 in 33000 years time. Well I guess the spacecraft lasted 35 years More information on the final attempt to contact Pioneer 10 here: http://www.unmannedspaceflight.com/index.p...indpost&p=44298 -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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