Mars Rovers - Spirit and Opportunity
If you have ever engineered something, or written software you know that even with a super effort there are things that you just cannot foresee. Usually however you can recall/patch or re-release. Not so when you send a mission to another planet. The standard needs to be exceptionally high, there is still some software control, but there are practical limits, and if you have ever read the notice “do not power off while updating” you’ll appreciate how risky updates can be. When Spirit and Opportunity landed on Mars the stated mission time was 90 days which you can only assume was a highly conservative estimate by the engineering team. Never was a 6 year mission considered. Remember that the goal for each rover was to drive up to 40 meters (about 44 yards) in a single day, for a total of up to one 1 kilometer (about three-quarters of a mile). Both goals have been far exceeded!
SPIRIT: Sol 2076 (Nov. 4, 2009, 2076 earth days since mission began), Spirit’s total odometry remains at 7,729.97 meters (4.80 miles).
OPPORTUNITY: Sol 2049 (Oct. 29, 2009, 2049 earth days since mission began), Opportunity’s total odometry is 18,622.44 meters (11.57 miles).
The mission has not been without issues however.
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Opportunity, which was due to land on a flat surface bounced into a crater on landing and took a while to get out although this did not impact the mission.
- On April 26, 2005 (Sol 446) Opportunity inadvertently dug itself into a sand dune, but after simulations on earth the rover was freed 38 days later.
- On Sol 2, an issue with the sholder arm was detected which eventually led to the “arm” permanently deployed.
- On January 4, 2007, both rovers received new flight software to the onboard computers allowing them to have more control over their power use by deciding when to take and send images or to send or when to take samples using its arm.
- Spirit, On January 21, 2004 (Sol 18), Spirit abruptly ceased communicating with mission control. It eventually turned out to be software issues which were resolved using an upgrade by Sol 33.
- Good news on March 9, 2005 the rover’s solar panel efficiency jumped from around 60% of what it had originally been to 93%, followed on 10 March by the sighting of dust devils.
- On March 16, 2006 JPL announced that Spirit’s troublesome front wheel had stopped working altogether. Despite this, Spirit was still making progress because the control team programmed the rover to drive backwards, dragging its broken wheel.
- On January 4, 2007, both Spirit also received new software.
Now comes the real issue. On May 1 2009 the SPIRIT rover had a wheel break through a crust on the surface of a crater and got caught in soft soil. Here is the image of where the Spirit rover is stuck. It would be sad to think that after only just having its flash memory fixed that it may not escape this sand trap. The attempts to reproduce the issue are impressive, so lets hope there is good news on Monday…..
Image from Spirit: possible its final resting place?
Here is the latest update from NASA.
2077-2083, Nov. 5-11, 2009: Flash Memory in Use Again
Spirit is preparing to attempt extrication from her embedded location at “Troy” on the west side of “Home Plate.”
The project was successful in reformatting Spirit’s on-board flash memory file system on Sol 2083 (Nov. 11, 2009). The rover is now again using the non-volatile flash file system for telemetry storage.
On Sol 2078 (Nov. 6, 2009), Spirit straightened her wheels in preparation for the first straight-ahead extrication drive, currently planned for Sol 2088 (Nov. 17, 2009). Spirit also collected another microscopic imager (MI) mosaic of the rover underbelly on Sol 2081 (Nov. 9, 2009).
As of Sol 2082 (Nov. 10, 2009), Spirit’s solar-array energy production was 368 watt-hours, with an atmospheric opacity (tau) of 0.569 and a dust factor of 0.5995. Total odometry remains at 7,729.97 meters (4.80 miles).