Remaining Mer Solar Power Extrapolation, helvick's Power Chart :) Options

[dilo]

helvick, your chart looks great but I'm little disappointed by the fact that Opportunity was so close to a "power death" one year ago!
If true, rover was unable to move or make complex operations. Indeed, it moved, taking many pictures and using robotic arm too!
Sol184 travel seq
Sol194 robotic arm
Also press release didn't mention any power issue (4 aug release), so there is something wrong?

[helvick]

If true, rover was unable to move or make complex operations. Indeed, it moved, taking many pictures and using robotic arm too!

Dilo,

There is certainly something wrong

First it was Spirit that hit rock bottom in terms of power, Spirit Daily updates for august 20004 look at the entry for 8/3/04, on sol 204 power dropped to 288 watt hours, Ouch! is right that's dangerously low. I also notice that my X-Axis Labels are offset a bit too much, the dip down to thewards the "Rover Death" line happened on sol204 but it looks like sol 225 from the chart labels, gotta fix that.

The chart includes both Spirit and Opportunity so it's a bit cluttered, I probably should split them apart and I'm beginning to think this thread should be in the "Imagery and Tech Issues" section as it's not Opportunity specific.

Secondly I only have about 25 data points from the daily updates between the two rovers and a further 5 or so from the Planetary society updates so a lot of the chart is interpolated. I really should add clear markers for the known data points.

[helvick]

You may get more info my dredging thru all the workbook sol-by-sol documentation.

I've been looking but haven't found anything apart from the occassional references in the Mission Managers daily reports which match the data points I already have. Lots of downloading and digging to go.

[dilo]

Dilo,

There is certainly something wrong

Ok, (damn!) now is clear... I fully agree with idea to split the two rovers in different plots... thanks.

[djellison]

I'll post any and all values I find in the documentation

Spirit
Sol 360 : 410 whrs


oh

That's the only one I could find

Just a thought - would you be prepared to share the .xls ( if that's what your using ) of the data?

Doug

[helvick]

Just a thought - would you be prepared to share the .xls ( if that's what your using ) of the data?

Here ya go. I've split the chart into two separate ones and tidied things up enough to be happy for folks to dig into if they feel the need.

Please feel free to crticise, point out errors and suggestions for improvement.

I dropped the shading box that highlights the split between "known" and extrapolated data, I wasn't too happy with the fact that it made it look as if the historical data was actually known - 99% of the data points are estimates as you will see if you look at the spreadsheets.

New known data points are just added into the relevant cell for the sol (Panel Output Confirmed Values column) on the Worksheet tabs and everything automatically recalculates.

It's zipped because it's a bit large (1.9Meg) - which is a bit excessive I know but I was working on making it easier to read rather than efficient. Seems outrageous for something to make sense of about 25 3 digit numbers.

Attached File(s)

 MERPower.zip ( 502.11K ) Number of downloads: 812

 

[general]

From the latest update:

http://marsrovers.jpl.nasa.gov/mission/sta...tml#opportunity

"The team has been watching Opportunity's power very carefully. It seems that Opportunity is losing some of the power boost it received during the last cleaning event. The solar array wake up time has been getting later each day and is currently 9:48 Mars Local Solar Time. The team has been planning accordingly, taking steps to preserve power where appropriate."

[helvick]

The solar array wake up time has been getting later each day and is currently 9:48 Mars Local Solar Time. The team has been planning accordingly, taking steps to preserve power where appropriate."  

Now if I had built my own Insolation table from 1st principles I'd be able to work out how serious that actually is. I'm making progress on that but I haven't got the kinks worked out yet (and learning more about eccentricity, equations of time, Zenith angles and all the rest than I'd ever thought I'd needed to know :-) ).

Based on my Insolation data I'd expect wake up time to be getting very slightly later in any case as total insolation peaked 4-6 weeks ago, although it's fairly flat at the moment as we pass through the SH Summer Solstice. Time to get back to work on my Equation of Time for Mars spreadsheet I think.

(Edit to correct Equinox to Solstice )

[Bob Shaw]

Is 9:48 Mars solar time based on whose clock? 24 hours, a proportion of a Sol or what...

...this is NOT intended to start a thread on Martian clocks, calendars, etc!

[helvick]

Is 9:48 Mars solar time based on whose clock? 24 hours, a proportion of a Sol or what...

...this is NOT intended to start a thread on Martian clocks, calendars, etc!

The Mission times are based on a 24 "hour" per Sol clock, that's what you get in the Nasa's Mars 24 application. AFAIK all Martian missions use it. Both Rovers use a Mission Time defined so that it would coincide with Local Solar time at a point about midway through their prime missions at their respective sites so theres a +-12 martian hour difference between them.

The precise details are bending my head at the moment so I'll stop there as I could go on ad nauseum.

[alan]

summer solstice on mars tomorrow (Aug 16)

[jamescanvin]

Just back from a talk by SS and I have the latest power figures:

As of "yesterday" (Sol 580?) Sprit was at 880WHr.

Oppy was at around 600WHr.

But...

Steve said in response to a question about remaining rover life that he didn't think that dust would be the cause of rover death. Rather there is not a lot of redundency in a lot of the electonics. There are a lot of electronic components that if they fail would be end of mission just like that

As Steve said "We plan every day as if it's our last, because it might be."

James

[dvandorn]

Problem is, they've been planning *every* day as if it will be their last since each vehicle's sol 1. Squyres himself, in his book, speaks of being very high-strung about anything that would take away a productive sol, because they only had 90 (or less!) to work with. He also speaks of the team getting more laid-back and less nervous about their babies dying anytime soon as they doubled, then tripled, then quadrupled their design lifetimes.

I wonder how hard it is to maintain that kind of emotional energy, to assume that your project (and your present Life As You Know It) is going to die soon -- keeping at that fever-pitch for month after month, caught in the tension between assuming you'll be dead tomorrow and hoping you'll survive indefinitely. I would think that would be nearly as exhausting, in the long run, as living on Mars time.

-the other Doug

[jamescanvin]

Of course, I'm sure Steve is more relaxed about it as time goes on but there is no getting away from the fact that sudden rover death is likely at some point so it's the way they have to work. The trick is not worrying about it! SS did mention today about how it's a hard way to work, making long term plans but making sure you are getting the maximum return day by day given you don't know what will happen tomorrow.

All I was trying to point out was that what with solar panel cleaning events and being able to stuggle on coping with several mechanical failures that at this point an electronic failure is seen (by SS) as the way the rovers will probably die. Thus all these power projections, while interesting probably arn't particuarly relevent to rover lifetimes.

James

[abalone]

Just back from a talk by SS and I have the latest power figures:

Steve said in response to a question about remaining rover life that he didn't think that dust would be the cause of rover death.

Can't believe how clean Oppy looks. Could have rolled out of the factory yesterday....

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