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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Jun 3 2017, 02:56 AM
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Junior Member Group: Members Posts: 83 Joined: 19-April 05 Member No.: 251 |
Do I remember right that Oppy's wheel motors have brushes? If so, how in the world (or how on Mars) can those brushes not be totally worn away? Yet Oppy keeps on going, and going, and going.....
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Jun 3 2017, 07:04 AM
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#3
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Senior Member Group: Members Posts: 1057 Joined: 17-February 09 Member No.: 4605 |
Yes, both drive and steering motors on Oppy are brushed which made good design sense given the 90 day, 700 metres driving distance mission success profile. The loss of the steering motor is possibly due to brushes as was the drive motor failure on Spirit, but given the staggering driving statistics for Opportunity the longevity of the motors is astounding. Well to be honest the Lithium Ion batteries are also performing brilliantly. I suspect that the lions share of the credit for both the performance of both batteries and drive motors accrues to the management of the MER engineering team and drivers.
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