[X] My Assistant

[Nirgal]

some time ago, helvick posted the following excellent analysis of the
MER solar power situation as an extrapolation of a diagram showing Watts/hours
against Sols.

http://www.unmannedspaceflight.com/index.p...ype=post&id=580
(originally posted in: http://www.unmannedspaceflight.com/index.p...722&#entry10722)

What makes this chart (let's call it Helvick's Power Chart, HPC so useful, is it's taking into account all relevant factors contributing to the remaining power life time of the rovers: seasonal solar input, gradual attenuation by dust accumulation, and (last not least the "pushing" of the cleaning events.

So here is my suggestion to use this thread/topic for updating this chart
whenever new power figures (watts/hours) and/or new cleaning events are
reported by JPL.

This would be a great way to always get an overview of the best guess of the maximum remaining rover life time (i.e. the limit imposed by the solar power...
which, of course does not take into account failure for other reasons, but would be a nice estimate of the maximum expected lifetime of our little heros

The latest JPL power report

The rover's power team reported a dust-cleaning event on Opportunity between sols 524 and 526. Daily power output from solar panels increased from about 500 watt hours to about 650 watt hours.

underlines the remarkable accuracy of the HPC:
helvick posted the chart on May 18 (aronud Sol 460) predicting the 500 Watts/hour for around Oppy-Sol 540 (note, that the chart shows Spirit-Sols),
which is very well in agreement with the new JPL report !

Now, with 650 Watts at Sol 530 after the cleaning event, the "critical-below-300-Watt-drop" would be deferred from (approx) Sol 680 to Sol 750, in other words:
about 70 extra Sols as a gift from the cleaning event ;-)

[djellison]

I think it'll be like gambling. Sometimes you win, sometimes you loose,but eventually, the house will always win and the output drops below a critical level.


Doug

[tedstryk]

I think it'll be like gambling. Sometimes you win, sometimes you loose,but eventually, the house will always win and the output drops below a critical level.
Doug

Well, depends how you look at it. Spirit and Oppy might win in the power situation category in the sense that this cleaning is efficient enough to allow them to live until they fall victim to some other kind of component failure that ends the mission. I will add that I really hope that these things continue their extended lives long enough to take full advantage of MRO...otherwise it seems that its communications package may go to waste, other than the Phoenix interlude, if MSL keeps getting pushed back.

[helvick]

Update to the original chart.

I'm stuck down at the bottom of a net free zone updating over GPRS so I'm just dipping in briefly. This is my current "best" guess based on the very few sample points we've been given. I also cleaned up my earlier data somewhat however it is now more obvious that the two main factors I didn't take into account, Tau and Rover Orientation, played a significant part in the very healthy Power state in the Sol 350-Sol 500 timeframe. Very slick orientation gave Oppy better than 100% of the theoretical level I calculated for it from Sol 275 to Sol 340 or so. The benefits of finding a nice sheltered Sun facing slope in mid winter are pretty clear.

Anyway - I'd love more data and really want to work this out a bit better but here's where i'm at so far

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