Opportunity General Health Options

[Doug M.]

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.

[fredk]

If you mean would the panels still provide the power they did at landing if they were clear of dust (and the illumination was the same), I don't recall any mention of that. My guess would be that the battery's ability to charge would be more of a problem, but again I don't recall any mention of its status. Remember that Spirit hit over 900 Whr at around sol 2000.

I don't think you mentioned the frozen steering actuator. Probably not fair to call it a "bad" driving motor, since it works but just gets a little hot sometimes.

Probably the best source to find lots of detail about all of these problems is the PS updates.

[Doug M.]

If you mean would the panels still provide the power they did at landing if they were clear of dust (and the illumination was the same), I don't recall any mention of that.

Well, all solar panels degrade gradually over time, and in space they go faster. The ISS arrays have a 15 year nominal lifespan; it's expected to be longer than that in practice, but OTOH the ISS arrays were designed and built with a large margin over the ISS' actual power needs. But given that nobody seems to be mentioning it, I suspect that it hasn't been a significant issue yet, or at least not as compared to dust, opacity, et al.

Your point about the batteries is a good one -- I hadn't thought of that. Googling turns up a number of papers from the rovers' first few years, basically saying "wow -- these lithium-ion batteries are holding up great!" Not seeing anything since 2010 one way or the other.


Doug M.

[MoreInput]

Your point about the batteries is a good one -- I hadn't thought of that. Googling turns up a number of papers from the rovers' first few years, basically saying "wow -- these lithium-ion batteries are holding up great!" Not seeing anything since 2010 one way or the other.

Here is an older paper about the performance of the batteries of the rover (only until sol 670): http://www.researchgate.net/publication/23...loration_Rovers
Here is the link to the battery manufacturer: http://yardney.com/

I couldn't find any newer material about this.