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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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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Jan 4 2009, 11:06 AM
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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 |
There are status updates on Ulysses at http://ulysses-ops.jpl.esa.int/ulsfct/the_..._continues.html
This is the latest, dated 11 December: Dear Ulysses colleagues, It has been a couple of months since my last status report. That's because nothing much has changed. We are continuing with our S-band science mission and typically we are now tracking once a day for about 2 to 4 hours. We don't want to increase pass durations much more than that because the temperature of the TWTA radiator panel (close to the cold hydrazine pipework) now falls rapidly when we switch the S-band transmitter on. But we are looking to increase our tracking time by taking two short passes per day separated by enough time for the radiator panel temperature to rise again. The data we have been getting recently has been of very good quality. The spacecraft-Earth distance has been decreasing and the link margin has increased to a point where we don't need to drop to 256 bps very often. In fact, we are close to being able to support 1024 bps which would enable us to get data from the tape recorder again. We're keeping a very close eye on the downlink SNR and we'll try 1k data again if we think the data quality won't be degraded. No promises though. There's another benefit from the low Earth range when coupled with the fairly low Earth drift rate that we're experiencing this month. If the hydrazine froze or ran out tomorrow, we could continue to acquire telemetry for around 20 days before the High Gain Antenna offpointing was too great to support even 128 bps. That's compared to about 5 days if the fuel had frozen back in May or June this year. However, this is a short-lived effect and by February next year, we'll only have 8 days of data before the end. |
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