What's Up With Ulysses?, alive? dead? cancelled soon? |
What's Up With Ulysses?, alive? dead? cancelled soon? |
Sep 27 2005, 04:05 AM
Post
#1
|
|
Member Group: Members Posts: 356 Joined: 12-March 05 Member No.: 190 |
What is up with the tiny Ulysses spacecraft that was launched in 1990 to study the solar whatever at high lattitudes? Last I heard it was in danger of dying because the RTG power was running low and at aphelion there was a risk of the hydrazine freezing/exploding in its propulsion system. Well that was like a year ago and I haven't heard anything since. It looks like it should've passed aphelion by now and should be out of danger.....
Its been going up there for over a full solar cycle, is it one of the missions on the chopping block because of the new humans on moon/mars thing? |
|
|
Feb 11 2007, 08:17 PM
Post
#2
|
|
Merciless Robot Group: Admin Posts: 8789 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
I agree with ustrax; the longevity of this spacecraft (and others) is astounding. These are arguably among the most complex devices ever built, yet without hands-on maintenance, periodic overhauls, etc., they just keep going. Wonder if the space agencies might be interested in building a few cars on the side...
All that aside, how much longer can Ulysses keep going given this new power conservation strategy? Also, is there any possibility that it will re-encounter Jupiter at some point? -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
|
|
|
Feb 11 2007, 08:44 PM
Post
#3
|
|
Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
Also, is there any possibility that it will re-encounter Jupiter at some point? Back when I was in university, a dozen of years ago I played with simulating Ulysses' orbit. In that occasion I "discovered" the second flyby of 2003. Ulysses crosses Jupiter's orbit every 6.5 years, and approaches it every 13 years, but IIRC, the encounter distance is increasing and there will be no more flybys during all of the 21st century. |
|
|
Feb 23 2008, 01:23 PM
Post
#4
|
|
Junior Member Group: Members Posts: 57 Joined: 21-September 06 Member No.: 1172 |
Back when I was in university, a dozen of years ago I played with simulating Ulysses' orbit. In that occasion I "discovered" the second flyby of 2003. Ulysses crosses Jupiter's orbit every 6.5 years, and approaches it every 13 years, but IIRC, the encounter distance is increasing and there will be no more flybys during all of the 21st century. I explored Ulysses orbit evolution with JPL HORIZONS system. Here are some interesting encounters till the end of XXI century: CODE Date (CT) Body CA Dist Vrel ---------------------- ----- -------- ------ A.D. 1992 Feb 08.78380 Juptr 0.006795 20.895 A.D. 2004 Feb 04.98546 Juptr 0.804396 13.984 A.D. 2086 Nov 13.65625 Juptr 0.780194 14.070 A.D. 2095 Nov 01.78213 Mars 0.056797 37.722 A.D. 2098 Nov 07.59152 Juptr 0.004053 24.594 November 7, 2098 Ulysses will be kicked out of the Solar system by Jupiter's gravity. Spacecraft's final trajectory will be highly hyperbolic (eccentricity~1.42), so it will be travelling very fast and one day, thousands years from now, Ulysses will reach some star. |
|
|
Feb 26 2008, 09:40 AM
Post
#5
|
|
Senior Member Group: Members Posts: 3652 Joined: 1-October 05 From: Croatia Member No.: 523 |
November 7, 2098 Ulysses will be kicked out of the Solar system by Jupiter's gravity. Spacecraft's final trajectory will be highly hyperbolic (eccentricity~1.42), so it will be travelling very fast and one day, thousands years from now, Ulysses will reach some star. I'm wondering how accurate HORIZONS data can possibly be for such distant dates. There has to be a number of unmodelled factors affecting orbital evolution of the spacecraft that the system doesn't take into account such as solar radiation pressure, slow outgassing from the spacecraft, etc. These will, given enough time, measurably perturb the orbit and I'm wondering what the real flyby distance and slingshot effect will be in 2098. Even tiny perturbations now can lead to large deviations in the future predicted passes. I wouldn't put my hand into the fire and say Ulysses is heading out of the solar system, let alone heading out on a highly hyperbolic trajectory. Move the closest approach point to Jupiter by a million km in one direction and it could end up being decelerated by Jupiter instead. EDIT: To give a sense of what I'm talking about, consider Jupiter's orbital velocity is 13 km/s and so it needs some 21 hours to cross a million kilometers. If Ulysses is early in its orbit by a mere 20 hours at the time of the 2098 flyby, the outcome could be radically different. A 20 hour cumulative in 90 years is really not much, especially since weak forces like light pressure tend to not change orbits much, but change their circumference a bit, which then brings timing differences that accumulate over time. -------------------- |
|
|
Lo-Fi Version | Time is now: 31st October 2024 - 11:27 PM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |