werner@aecom.UUCP (Craig Werner) (07/12/85)
Condensed fr. NY Daily News, by Edward Edelson, Science Editor. While the publicity builds for Halley's comet, Voyager II is plodding steadily at 40,000 mph towards another planetary encounter. When it reaches it's next target, Uranus, Voyager will be more than eight years from Earth and more than four years past its last target, Saturn. Comparatively little is known of Uranus. What is known that Uranus is 64X the volume of the Earth, has five moons and a tedious set of dark rings, discovered only in 1969. Most of the work will be done in a few hours when Voyager makes its closest approach at 1 pm next January 24. (Mark your calendar -:)) The data will actually reach Earth 2 hrs 43 min later, from the satellites 25 watt radio transmitter (Only 25 watts - pretty amazing reception, if you ask me!) After that it will reach Neptune on Aug 24, 1989, and then be propelled downward out of the solar system. (It's companion, Voyager I was propelled upward out of solar system immediately after encountering Saturn) Signals should come from the satelites as long as their power holds out, which could be as late as 2005 or 2010. (They run on Nuclear decay, if I am not mistaken.) -- Craig Werner !philabs!aecom!werner "The world is just a straight man for you sometimes"
bobn@bmcg.UUCP (Bob Nebert) (07/17/85)
> While the publicity builds for Halley's comet, Voyager II is plodding > steadily at 40,000 mph towards another planetary encounter. > After that it will reach Neptune on Aug 24, 1989, and then be propelled > downward out of the solar system. (It's companion, Voyager I was propelled > upward out of solar system immediately after encountering Saturn) >> >> Is Voyager I or II the space craft that the plaque was installed indicating >> Man, Woman, Earth's position in our solar system, etc?? I forgot. >> >> Also, after it leaves our solar system, what type of data will it >> transmit back? >> If it is just going to ramble I can't see justifing to expense but >> they must have some goal for it don't you think. >> My opinion is to have it do a wide circle and go back toward Earth. >> By the time it came back we would have the space shuttle perfected >> enough to retrieve it. An awful lot of info can be recovered from a >> returned intersystem vehicle. >> >> Anybody care to comment >> >> --bobn-- >> sdcsvax!bmcg!bobn >>
doug@escher.UUCP (Douglas J Freyburger) (07/18/85)
A while ago, there were some questions about Voyager 2s condition and what its chances are of hitting or being thrown seriously off course by gravity from Uranus's moons. I talked it over with one of my friends in celestial navigation and got this: Noone is quite sure of the mechanical condition of the machine, but they believe it is quite fine. There is more worry about radiation damage to the electronics. It turns out that most of the electronics slowly recovers from radiation damage if it is powered down, but there is the tradeoff that something powered down might never come back. Also most of the more critical circuitry in attitude control, etc can't realistically be turned off. It's to risky, so they eat the accumulated radiation dameage. For the orbital path, the moons of Uranus are quite small, so there is very little chance of an impact. Even an encounter close enough to seriously effect the trajectory is very unlikely. For moons of a body not yet visited, the uncertainty in the orbit is VERY great. Several orders of magnitude greater than the size of the bodies, so even if you WANTed to impact one, you'd be hard pressed. On its pass through Saturn's system one of the V's ended up on an impact course with Titan because of these uncertainties. They had several days to make the burn, but there were still plenty of nervous space scientist types around here at the time. There also seems to be plenty of delta-V left worth of fuel, so any maneuvers to get closer to the moons will be "no problem".
alb@alice.UUCP (Adam L. Buchsbaum) (07/18/85)
On the subject of Voyager 2's condition, there are two major systems with problems. One is the main receiver. It doesn't work at all. The backup does work but has problems locking on to Earth-based signals in certain temperature ranges; JPL people in charge, though, say they have worked away around this and that it shouldn't pose a problem. The other problem is that, during the passby of Saturn, some damage was sustained in the mechanisms that move the camera platform, causing it to stick at times. Again, JPL said that there should be no problem with this as the platform seems to move just fine if moved slowly. Also, they have learned how to point the cameras by rotating the entire spacecraft.
henry@utzoo.UUCP (Henry Spencer) (07/19/85)
There is one such uncertainty, associated with the 1989 Neptune encounter
rather than the Uranus encounter: nobody knows whether Neptune has rings
or not. There is some evidence that it might. The trajectory tentatively
planned for the Neptune encounter may have to be revised, because if the
ring reports are true, the trajectory takes Voyager straight into them.
Going to a more conservative trajectory would be a pity, because the Neptune
encounter (unlike the Uranus one) is not constrained by the need to reach
the next planet, and the planned path includes a very close flyby of Triton.
--
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,linus,decvax}!utzoo!henryhenry@utzoo.UUCP (Henry Spencer) (07/19/85)
The problem with the scan platform on Voyager 2 is particularly annoying
for the Uranus encounter, because Voyager is going through the Uranus
system at almost a right angle to the plane of Uranus's moons. This means
a fairly brief close-encounter phase with interesting objects in several
well-separated directions. One can safely predict considerable tearing of
hair over the final pointing schedule, given the need to move the platform
slowly if at all.
--
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,linus,decvax}!utzoo!henryeugene@ames.UUCP (Eugene Miya) (07/21/85)
> >> Is Voyager I or II the space craft that the plaque was installed indicating > >> Man, Woman, Earth's position in our solar system, etc?? I forgot. > >> > >> Also, after it leaves our solar system, what type of data will it > >> --bobn-- > >> sdcsvax!bmcg!bobn Pioneer 10/11 have a controversial plack design by Carl Sagan's second wife showing a pair of naked humans and a crude star map of our galatic position. My favorite space-political cartoon by Paul Conrad has two clothed aliens looking on saying: The people of earth are just like us, except they're not clothed." Voyagers 1/2 have record "Sounds of the Planet Earth" which was mentioned in Star Trek I and Starman with digitized pictures and sounds of earth as well a map, and a design to build a 'player.' This was designed by Carl and his then to be third wife and some one else. A book was published entitled Murmers of Earth, I believe. --eugene miya NASA Ames Research Center {hplabs,ihnp4,dual,hao,decwrl,allegra}!ames!aurora!eugene
eugene@ames.UUCP (Eugene Miya) (07/22/85)
> There is one such uncertainty, associated with the 1989 Neptune encounter > rather than the Uranus encounter: nobody knows whether Neptune has rings > or not. There is some evidence that it might. The trajectory tentatively > planned for the Neptune encounter may have to be revised, because if the > ring reports are true, the trajectory takes Voyager straight into them. > > Going to a more conservative trajectory would be a pity, because the Neptune > encounter (unlike the Uranus one) is not constrained by the need to reach > the next planet, and the planned path includes a very close flyby of Triton. > -- > Henry Spencer @ U of Toronto Zoology > {allegra,ihnp4,linus,decvax}!utzoo!henry There are many uncertainies. Most are not visible to the naked eye: radiation belts, large magnetic anomalies from satellites, gravitational anomalies, intermediate swarms of astroids at a distance we cannot detect. Some experiements such as the radio astronomy experiments must take place on the lee side of the planet in order to get some idea which the upper atmospheres are like. Too bad the original Grand Tour mission was not approved. --eugene miya NASA Ames Research Center {hplabs,ihnp4,dual,hao,decwrl,allegra}!ames!aurora!eugene @ames-vmsb.ARPA:emiya@jup.DECNET
eugene@ames.UUCP (Eugene Miya) (07/22/85)
> > >> Also, after it leaves our solar system, what type of data will it > > >> --bobn-- > > >> sdcsvax!bmcg!bobn I forgot to answer this: It will collect data on the nature of interstellar space, the boundary of the solar system with that space where the solar winds die out. It will look at phasma and electromagnetics. This is currently being done with Pioneer and Voyager I. --eugene miya NASA Ames Research Center {hplabs,ihnp4,dual,hao,decwrl,allegra}!ames!aurora!eugene
cramer@kontron.UUCP (Clayton Cramer) (07/25/85)
> > > >> Also, after it leaves our solar system, what type of data will it > > > >> --bobn-- > > > >> sdcsvax!bmcg!bobn > > I forgot to answer this: > It will collect data on the nature of interstellar space, the boundary > of the solar system with that space where the solar winds die out. > It will look at phasma and electromagnetics. This is currently being > done with Pioneer and Voyager I. > > --eugene miya > NASA Ames Research Center > {hplabs,ihnp4,dual,hao,decwrl,allegra}!ames!aurora!eugene The more important question (at least to me) is, where is it going to? I worked on Voyager back around 1976, and I asked one of the researchers once, "What star is going closest to? And how close will it get?" I got a "We'll get back to" type of response. So again, nine years later, "Where's it going?"
mink@cfa.UUCP (Doug Mink) (07/26/85)
[]
I found out a few days ago that JPL is really worried about Neptune's
*ring* preventing a Triton encounter when they called to ask for a
preprint of a paper I just wrote on stellar occultations by Neptune
through 1990. They're going to observe as many as possible to get
some statistics on the *ring*. The *ring* will be hard to track
down, though, as many careful occultation observations have failed
to show it--I've co-authored two papers which report a lack of an
observable ring around Neptune. The occultation business was getting
sort of boring; Neptune seems to keep livening things up.
__
Doug Mink
Harvard-Smithsonian Center for Astrophysic
{harvard|genrad|allegra|ihnp4}!wjh12!cfa!mink
normally in Cambridge, Mass.,
but at Johnson Space Center, Houston, for Spacelab 2.ethan@utastro.UUCP (Ethan Vishniac) (07/27/85)
> > The more important question (at least to me) is, where is it going to? > I worked on Voyager back around 1976, and I asked one of the researchers > once, "What star is going closest to? And how close will it get?" I > got a "We'll get back to" type of response. > > So again, nine years later, "Where's it going?" Nowhere. It is not pointing anywhere near the nearest stars. By the time it gets very far all the stars will have moved. We have no idea where it might end up, but odds are that it will never pass close to another planetary system. -- "Don't argue with a fool. Ethan Vishniac Borrow his money." {charm,ut-sally,ut-ngp,noao}!utastro!ethan Department of Astronomy University of Texas
al@aurora.UUCP (Al Globus) (07/31/85)
Regarding Voyager 2 which is heading for Uranus... > >> > >> Also, after it leaves our solar system, what type of data will it > >> transmit back? Possibly solar wind data, I'm not sure though. > >> My opinion is to have it do a wide circle and go back toward Earth. Not enough propellant by several orders of magnitude. Sorry.
eugene@ames.UUCP (Eugene Miya) (08/01/85)
> > > > The more important question (at least to me) is, where is it going to? > > I worked on Voyager back around 1976, and I asked one of the researchers > > once, "What star is going closest to? And how close will it get?" I > > got a "We'll get back to" type of response. > > > > So again, nine years later, "Where's it going?" > > Nowhere. It is not pointing anywhere near the nearest stars. By the time > it gets very far all the stars will have moved. We have no idea where it > might end up, but odds are that it will never pass close to another > planetary system. > -- > Ah, found it! Sorry Ethan, this is not entirely true. While it is true that there is no deliberate target, someone at JPL [sorry, forgot to copy his name down, he deserves the credit] calculated the motions of local stars to 100,000 years. Both Voyagers will pass to around 1 Light-year (approx) of the star AC +79 3888 in about 40,000 years. AC +79 3888 is currently 17 light years away and is expected to be about 3 light years away by that time. [The velocity is left as an excercise to elementary school students...]. ;-) After Neptune encounter of V 2, a decision will be made whether to use the remaining manuveuring fuel to improve the current trajectory for a closer encounter with AC +79 3888. --eugene miya NASA Ames Research Center {hplabs,ihnp4,dual,hao,decwrl,allegra}!ames!aurora!eugene emiya@ames-vmsb
ethan@utastro.UUCP (Ethan Vishniac) (08/01/85)
> > > > > > So again, nine years later, "Where's it going?" > > > > Nowhere. It is not pointing anywhere near the nearest stars. By the time > > it gets very far all the stars will have moved. We have no idea where it > > might end up, but odds are that it will never pass close to another > > planetary system. > > Sorry Ethan, this is not entirely true. While it is true that there is no > deliberate target, someone at JPL [sorry, forgot to copy his name down, > he deserves the credit] calculated the motions of local stars to 100,000 > years. Both Voyagers will pass to around 1 Light-year (approx) of the > star AC +79 3888 in about 40,000 years. AC +79 3888 is currently 17 > light years away and is expected to be about 3 light years away by that time. > [The velocity is left as an excercise to elementary school students...]. ;-) > After Neptune encounter of V 2, a decision will be made whether to use the > remaining manuveuring fuel to improve the current trajectory for a > closer encounter with AC +79 3888. > > --eugene miya Hmmmmmm.......................... Anyone out there who thinks one light year counts as close can call me a liar. -- "Don't argue with a fool. Ethan Vishniac Borrow his money." {charm,ut-sally,ut-ngp,noao}!utastro!ethan Department of Astronomy University of Texas
ethan@utastro.UUCP (Ethan Vishniac) (08/01/85)
> > > > Sorry Ethan, this is not entirely true. While it is true that there is no > > deliberate target, someone at JPL [sorry, forgot to copy his name down, > > he deserves the credit] calculated the motions of local stars to 100,000 > > years. Both Voyagers will pass to around 1 Light-year (approx) of the > > star AC +79 3888 in about 40,000 years. AC +79 3888 is currently 17 > > light years away and is expected to be about 3 light years away by that time. > > [The velocity is left as an excercise to elementary school students...]. ;-) > > After Neptune encounter of V 2, a decision will be made whether to use the > > remaining manuveuring fuel to improve the current trajectory for a > > closer encounter with AC +79 3888. > > > > --eugene miya Actually, something about this puzzles me. Assuming that the space velocity of AC +79 3888 is only known to within 1 km/sec I get that even we aimed something at that star we would expect to miss by 13% of a light year. This is about a trillion kilometers (about 8000 AU). Admittedly there may be no other use for the manuveuring fuel than aiming at AC +79 3888, but no one could reasonably expect anyone there to notice it as it goes by. I'm not much on velocity determinations, but isn't this basically right? -- "Don't argue with a fool. Ethan Vishniac Borrow his money." {charm,ut-sally,ut-ngp,noao}!utastro!ethan Department of Astronomy University of Texas
eder@ssc-vax.UUCP (Dani Eder) (08/02/85)
> > > > So again, nine years later, "Where's it going?" > > Nowhere. It is not pointing anywhere near the nearest stars. By the time > it gets very far all the stars will have moved. We have no idea where it > might end up, but odds are that it will never pass close to another > "Don't argue with a fool. Ethan Vishniac > Borrow his money." {charm,ut-sally,ut-ngp,noao}!utastro!ethan > Department of Astronomy > University of Texas I believe you are correct that it will never pass close to another planetary system but for a different reason. Long before it will get anywhere significant at all in interstellar terms, someone will go and retrieve it to put it in the Smithsonian. Dani Eder Boeing Aerospace Company. Advanced Space Transportation Organization
andrew@alberta.UUCP (Andrew Folkins) (08/03/85)
In article <1065@ames.UUCP> eugene@ames.UUCP (Eugene Miya) writes: > Both Voyagers will pass to around 1 Light-year (approx) of the >star AC +79 3888 in about 40,000 years. I have this feeling that both spacecraft will be in the Smithsonian long before then . . . -- Andrew Folkins YABS : If you think education is expensive, ihnp4!alberta!andrew consider the price of ignorance.
sean@ukma.UUCP (Sean Casey) (08/06/85)
In article <82@ssc-vax.UUCP> eder@ssc-vax.UUCP (Dani Eder) writes: > I believe you are correct that it will never pass close to another >planetary system but for a different reason. Long before it will get >anywhere significant at all in interstellar terms, someone will go and retrieve >it to put it in the Smithsonian. I hope so. I really do. "You can't track in Hyperspace." - H. Solo -- - Sean Casey UUCP: sean@ukma.UUCP or - Department of Mathematics {cbosgd,anlams,hasmed}!ukma!sean - University of Kentucky ARPA: ukma!sean@ANL-MCS.ARPA
peter@baylor.UUCP (Peter da Silva) (08/13/85)
> In article <82@ssc-vax.UUCP> eder@ssc-vax.UUCP (Dani Eder) writes: > > I believe you are correct that it will never pass close to another > >planetary system but for a different reason. Long before it will get > >anywhere significant at all in interstellar terms, someone will go and retrieve > >it to put it in the Smithsonian. > > I hope so. I really do. I second that emotion. -- Peter da Silva (the mad Australian) UUCP: ...!shell!neuro1!{hyd-ptd,baylor,datafac}!peter MCI: PDASILVA; CIS: 70216,1076
dhp@ihnp3.UUCP (Douglas H. Price) (08/17/85)
That brings up an interesting point. How close (and when) will star AC +79 3888 be at its closest approach to the solar system? Which stars (that are currently being tracked) will approach closer than 3 light years in the next 100,000 years? -- Douglas H. Price Analysts International Corp. @ AT&T Bell Laboratories ..!ihnp4!ihnp3!dhp
friesen@psivax.UUCP (Stanley Friesen) (08/21/85)
In article <464@utastro.UUCP> ethan@utastro.UUCP (Ethan Vishniac) writes: > >Actually, something about this puzzles me. Assuming that the space velocity >of AC +79 3888 is only known to within 1 km/sec I get that even we aimed >something at that star we would expect to miss by 13% of a light year. >This is about a trillion kilometers (about 8000 AU). Admittedly there >may be no other use for the manuveuring fuel than aiming at AC +79 3888, >but no one could reasonably expect anyone there to notice it as it goes >by. I'm not much on velocity determinations, but isn't this basically >right? >-- Well, there is another reason why no-one is likely to notice them. If I remember my stellar naming conventions and relative magnitudes correctly, that star is likely to be a *very* dim type 'M' dwarf. A planet would have to be closer to it than Mercury is th the Sun to even have a hope of liquid water, let alone a reasinable atmosphere, so - *no* life at all to notice anything. Sigh, wouldn't Tau Ceti have been better? :-) Well, I guess it *could* be a low end type 'K' - still not much hope for life though. -- Sarima (Stanley Friesen) {trwrb|allegra|cbosgd|hplabs|ihnp4|aero!uscvax!akgua}!sdcrdcf!psivax!friesen or {ttdica|quad1|bellcore|scgvaxd}!psivax!friesen