Opportunity General Health |
Opportunity General Health |
Aug 15 2013, 10:25 AM
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#1
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Member Group: Members Posts: 102 Joined: 8-August 12 Member No.: 6511 |
I've been clicking around for a general health status for Opportunity, but haven't been able to find one.
Power -- The solar panels seem to be showing signs of degradation over time but it's not clear how much. NASA reports regularly on power output, tau/opacity and dust levels, but not on the status of the panels themselves. They did clock well over 500 watt-hours as recently as May, so it doesn't look like their performance is a serious issue. As for non-solar power, the radioisotope heaters seem to be fine; they're Pu-238, so they would only have lost about 10% of their power since launch. So the WEB is still toasty. Motors and joints -- I know we've got one bad wheel motor (which means we spend a lot of time driving backwards) and the bad arm azimuth joint and the separate issue with the arm potentiometer. Electronics -- There was the flash memory issue earlier this year but I don't know if that was a one-off or a sign of age. Instruments -- The Mossbauer spectrometer is done because its radioactive cobalt source ran out. MiniTES got dust on its mirror after the big 2007 dust storm and stopped working. AFAICT the other instruments are okay? Pancam, Navcam, Hazcams, and the APXS all seem to be working fine. There was a NASA press release last month that said "Opportunity imaged the Rock Abrasion Tool (RAT) bit to assess remaining bit life", but it didn't say anything about what they saw and I haven't been able to find any more information. Clearly the RAT is still working, at least for now. What else? Doug M. |
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Apr 27 2018, 03:13 PM
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#2
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Senior Member Group: Members Posts: 1592 Joined: 14-October 05 From: Vermont Member No.: 530 |
"Relatively finite." Are you using inductive reasoning to conclude that Opportunity's lifetime is approaching infinity?
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Apr 27 2018, 09:59 PM
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#3
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Newbie Group: Members Posts: 15 Joined: 21-January 10 Member No.: 5183 |
"Relatively finite." Are you using inductive reasoning to conclude that Opportunity's lifetime is approaching infinity? Imagine the headaches that would cause! ;-) The article (linked above) shows brushes + friction = resulting in predictable wear / gouging. That cannot go on forever (!), so the motors, relative to other items on the rover have an end of life date. My thought was 'what wear is there in a brushless motor?' - which then leads to why didn't they use brushless - which then leads to advantages vs disadvantages etc... |
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Apr 27 2018, 11:18 PM
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#4
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Member Group: Admin Posts: 976 Joined: 29-September 06 From: Pasadena, CA - USA Member No.: 1200 |
... My thought was 'what wear is there in a brushless motor?' - which then leads to why didn't they use brushless - which then leads to advantages vs disadvantages etc... We'll see Curry actuators how they survive there. Although I'm no expert, brushless require a more complex electronics, and if you think that electronics is more robust than mechanical components, think again. Out of 17 actuators we use almost every day, only two have issues) while most of the flash file system (which has no moving parts) have issues, and even Curry had some serious issues with one of the flash gates. If I had to rebuild MER all over again, I'm not so sure the brushed motors would be the first items on my list. Paolo -------------------- Disclaimer: all opinions, ideas and information included here are my own,and should not be intended to represent opinion or policy of my employer.
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Apr 28 2018, 12:17 AM
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#5
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Member Group: Members Posts: 691 Joined: 21-December 07 From: Clatskanie, Oregon Member No.: 3988 |
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Apr 28 2018, 06:46 AM
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#6
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Member Group: Admin Posts: 976 Joined: 29-September 06 From: Pasadena, CA - USA Member No.: 1200 |
The MER design has proven itself to be solid and reliable. I hope the design could someday be used again, perhaps with some upgraded electronics components and a different set of instruments. There are two things I would redesign: 1) Move the UHF and HGA to a higher place. So many times I had to negotiate the vehicle attitude with communication requirements! 2) have the solar deck tilted about 20 degrees. No more hunting for high tilt in Wintertime. 3) and of course I would like Google Fiber from Mars. Paolo -------------------- Disclaimer: all opinions, ideas and information included here are my own,and should not be intended to represent opinion or policy of my employer.
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Apr 28 2018, 07:52 PM
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#7
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Member Group: Members Posts: 715 Joined: 22-April 05 Member No.: 351 |
There are two things I would redesign: Maybe ultraflex solar panels for more power This thread isn't totally idle speculation. The Mars community is considering a line of future MER-size rovers to explore the diversity of surface types with past histories of water. With modern instruments, it could be really nice upgrade. I suspect that a precision landing system would also be high on the list for a future rover line. Would be nice to have a single general purpose heat source RTG (MMRTG's have 8) to supplement the solar array for survival heating and power during dust storms. Of course, the mission cost just sky rocketed due to the certifications. -------------------- |
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Apr 29 2018, 05:50 PM
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#8
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Member Group: Members Posts: 691 Joined: 21-December 07 From: Clatskanie, Oregon Member No.: 3988 |
Maybe ultraflex solar panels for more power. More power maybe, but what about deployed rigidity? A rover going over rocks and pot holes in the road no doubt will put alot of vibrational stress on the bonded cells and structure. Was there ever testing done on this for the MAX-C concept? |
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