What's Up With Ulysses?, alive? dead? cancelled soon? |
What's Up With Ulysses?, alive? dead? cancelled soon? |
Sep 27 2005, 04:05 AM
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#1
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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? |
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Mar 17 2009, 04:54 PM
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#2
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
The latest mission status. Ulysses is still alive!
Status report: 20-Feb-2009 Date: Thu, 20 Feb 2009 11:45:38 -0800 From: Nigel Angold Subject: Ulysses Status Update 5 Dear Ulysses colleagues, Yesterday was mission day 6712 and we surpassed 400 days of S-band mission operations. Given that we thought the spacecraft would only survive a few months after the X-band transmitter failure on 15 January 2008, that's pretty good going! The last month or so has seen a dramatic increase in data return. This is due in part to a request by NASA HQ for additional DSN coverage and also due to the fact that we can record and play back data again on board the spacecraft. That's possible because the spacecraft-Earth distance is low enough to support a 1024 bps telemetry data rate at the moment (this situation will last until sometime in mid-March). I've attached a plot of our weekly data return percentages which clearly shows the recent improvements. As far as the hydrazine is concerned, it's obviously not frozen yet, but there can't be very much left. Our estimate is that we have almost no fuel left even using our best-case estimates. However, it's very difficult to get an exact figure of fuel usage over the mission given that we have had about 3 years of closed-loop conscan operations to control nutation when the spacecraft fired the thruster autonomously. During those periods, we had to estimate the number of pulses fired by monitoring the increase in catalyst bed temperature after each period of thruster activity which is not the easiest thing to do. So the bad news is that we don't have an exact estimate of how much fuel is left but the good news is that it's still above zero! We hope that the data returned is continuing to excite you as the solar activity slowly begins to increase. Best regards, Nigel |
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