New Horizons Hibernation and Cruise to Pluto |
New Horizons Hibernation and Cruise to Pluto |
Aug 7 2007, 03:34 PM
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#16
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Actually, Gordon, the odds are that you're probably right about it being software. It really is impossible to test every possible case (or even foresee them all), so hopefully this is just an easy to find & fix bug.
-------------------- 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.
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Aug 7 2007, 04:14 PM
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#17
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Senior Member Group: Members Posts: 1582 Joined: 14-October 05 From: Vermont Member No.: 530 |
I do hope this turns out to be a weird software issue rather than a hardware problem even though extensive ground testing probably makes software bugs less likely. I hope it's neither. I hope it was an uncorrectable, transient, radiation-induced error. What will be most interesting is how deep the safe mode is, and how graceful the failure is. |
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Aug 7 2007, 04:26 PM
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#18
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Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
I hope it was an uncorrectable, transient, radiation-induced error. That wouldn't be too good, either. It would mean the spacecraft is too sensitive to random, unpredictable cosmic-ray events even while in the state of hibernation when most of the electronics are powered off. Imagine a trip like that during Pluto closest approach. I'd actually put those kinds of faults in the hardware "fault" category. -------------------- |
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Aug 7 2007, 05:31 PM
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#19
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Senior Member Group: Members Posts: 1582 Joined: 14-October 05 From: Vermont Member No.: 530 |
That wouldn't be too good, either. It would mean the spacecraft is too sensitive to random, unpredictable cosmic-ray events even while in the state of hibernation when most of the electronics are powered off. Imagine a trip like that during Pluto closest approach. I'd actually put those kinds of faults in the hardware "fault" category. I think it was reading the GP-B updates with all the talk of multi-bit errors that makes me think they're something you have to live with... GP-B dealt with them far more often than 1 in 2 years. i.e. http://einstein.stanford.edu/highlights/hl_040105.html "Investigations into the root causes of the recent spate of MBEs suggests the possibility that the scrub routine which is checking the memory cells of the on-board Command & Control Computer Assembly (CCCA) could trigger a safemode response on a single MBE if that error occurs in certain locations. As a result, the team has re-programmed the safemode response for the MBE test to automatically stop the mission timeline, rather than rebooting the computer." |
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Aug 7 2007, 05:42 PM
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#20
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Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
Oh, they're something you have to live with, alright. Statistics are hell, but it just doesn't seem right for the spacecraft to run into a red alert mode only some 2 months (?) into hibernation. Statistically, that can mean anything from an unlucky fluke to a spacecraft that has to be babysitted every month. It could be a combination of the two for all we know, a cosmic ray trip triggers a software corrective action that's buggy and you wind up in a reset.
Take Cassini for comparison - it has a couple of trips of a certain power-related circuit (I forget) per year due to cosmic rays and that's with a spacecraft doing stuff basically 24/7. The fact NH had a mostly trouble-free flight up until hibernation does seem to suggest it's in some way related to that mode, but all this is wild speculation. Hopefully, Alan and co. will find out the real sequence of events soon enough. -------------------- |
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Aug 8 2007, 07:52 AM
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#21
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Member Group: Members Posts: 529 Joined: 19-February 05 Member No.: 173 |
Status: Recovering. DSN Allocating Additional Shifts to Assist in Recovery.
Root Cause of C&DH Reset: Remains TBD. Team: Working Long Hours; Need to Pace. Prospect: Back in Hibernation in <1 Week. |
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Aug 8 2007, 10:10 AM
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#22
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Thanks for the update, Alan. Best of luck to the team, and sympathy for the long, long hours...please tell them we REALLY appreciate their efforts!!!
-------------------- 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.
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Aug 8 2007, 10:16 AM
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#23
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Newbie Group: Members Posts: 19 Joined: 17-June 07 From: Near Southampton, UK Member No.: 2430 |
Thanks for the update Alan. I've lived through all the first visits to the Moon and other planets and I do so want New Horizons to make it to Pluto. Best of luck to you all!
Fingers Crossed, Chris. |
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Aug 8 2007, 02:54 PM
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#24
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Senior Member Group: Admin Posts: 4763 Joined: 15-March 05 From: Glendale, AZ Member No.: 197 |
Prospect: Back in Hibernation in <1 Week. You or the spacecraft? -------------------- If Occam had heard my theory, things would be very different now.
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Aug 10 2007, 09:00 AM
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#25
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Member Group: Members Posts: 529 Joined: 19-February 05 Member No.: 173 |
Recovery complete! New Horizons is back to nominal hibernation.
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Aug 10 2007, 09:02 AM
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#26
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Founder Group: Chairman Posts: 14431 Joined: 8-February 04 Member No.: 1 |
Wake up, scratch, roll over, go back to sleep.
We've all been there. Thanks for the updates Alan. Doug |
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Aug 10 2007, 04:39 PM
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#27
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Excellent. Alan, if you get a chance, could you please tell us what seemed to be the most probable cause of this event? Interesting.
-------------------- 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.
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Aug 11 2007, 06:29 AM
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#28
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Member Group: Members Posts: 529 Joined: 19-February 05 Member No.: 173 |
Nprev-- Forensics continue down at the 1's and 0's level to learn why the reboot occurred. Attention is focusing on a possible (and subtle) C&DH software interaction with autonomy rules.
-Alan |
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Aug 11 2007, 08:11 PM
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#29
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Yep; that's exactly what I meant earlier about it not being possible to test every case when it comes to software. Thanks, Alan!
-------------------- 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.
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Sep 18 2007, 04:30 PM
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#30
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Newbie Group: Members Posts: 6 Joined: 11-April 07 From: California Member No.: 1961 |
Hello Alan,
I read somewhere in a response to the media that the code for the Pluto encounter will be designed and written this year and in '08. Then, in '09, there would be a first rehearsal. Does this mean a major wakeup in '09? Any details of what that will entail? Thanks. |
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