Now that Opportunity has surpassed Viking 1 in mission duration (longest surface mission) I tried to find some orbital spacecraft for new milestones.


Mission, Orbital Insertion-Mission Ended, Duration, Date Spirit Should Surpass

Galileo, 12/07/1995-09/21/2003, 2846 days, 10/19/2011
MGS, 09/11/1997-11/05/2006, 3343 days, 02/27/2013
PV*, 12/04/1978-10/08/1992, 5058 days, 11/08/2017

*Pioneer Venus


Mars Odyssey and both Voyagers entered operation before MER and hopefully won't be ending for a long, long time.
(All figures are hopefully within a day or two. Feel free to correct me.)


Edit: BTW, Odyssey should be surpassing MGS in "at Mars duration" on December 18th.

Edit Edit: Corrected for VP end of mission date. (Thank you Paolo.)

PV was lost on 8 October 1992 and was still transmitting when it "aerobraked"

Time for an update...

The upturn in energy for Opportunity is the result of minor panel cleaning events rather than coming out of the winter solstice.

hi Dilo!

Is it possible to post the raw data of your diagrams?
Just to play with it and make some stupid statistics on my own.

thanks,
Moreinput

Sure, this is my updated file in .xls format (original is .ods, but I think is limited in compatibility)- I removed plots-

My monthly update:

Great energy increase in the 2nd half of June!

Here is a graph showing the weekly values of Opportunity's Watt Hours, Tau, and Dust Factor (as stated in the weekly Opportunity Updates on the main Mars Rover website) from January 2010 to July 15, 2010.



Low tau's are good -- high dust factors are good.
A tau of 4.7 is a 99% blocked atmosphere - we are in a very clear sky period ( t=0.2)
I am assuming a dust factor of 1.0 is how Oppy left the clean-room.

Notice when Tau goes up (sol 2253) and the Dust Factor goes down, the power goes down. And when tau is very low (sol 2300) and the dust has been cleaned off (0.7) the power zooms (for what is available in winter!). The winter solstice was Sol 2260 ( i think?)

For a review of Tau, I refer you to Emily's awesome recap of the (click) 2007 Dust Storm
I haven't found a good description of the dust factor yet(!)

Cheers

Cool plot, thanks PDP8E!

I've been hoping someone would do that! Thanks PDP. That shows nicely how we've climbed out of the 50% dust factor level we'd been mired in for so long.

One little request: would you consider showing the individual data points the next time you do a plot?

There's not much to it - it's just the percentage of light that gets through the dust coating the panels. It drops as dust settles onto the arrays (usually slowly), and rises as wind gusts clean the arrays off (can be very suddenly).

Thanks Dilo and FredK

I was wondering if Tau was zero and the dust factor was 100% what are the Whrs differences between Winter solstice and Summer solstice. A nice sine function between those points should give you the maximum possible Whrs on any given Martian day (depending on latitude)

That's an interesting question. Presumably it wouldn't be precisely a sinusoid, even if the solar arrays were level. In addition to the varying incidence angle, the total hours that the Sun is up vary with time of year. And the incidence angles in morning and late afternoon are low even when the Sun climbs high at local summer. I'm sure someone has done an accurate calculation...

Some of Helvick's early posts in the old Whrs thread have a max power curve - for example here

Remember the days when we thought 400Whrs was needed to do anything, and rover death was at 290?

For baseball nuts who love stats: Considering the 70m restraint vs. now driving three sols in a row, I wonder what distance record Oppy might set for some period of time like 3 or 5 or 10 or 100 sols.

I need to slightly anticipate my monthly update because I could have some connection trouble in the next month due to home transfer...