OPPORTUNITY UPDATE: Poking Around on the Plains - sol 360-366, February 04, 2005
Opportunity continues to be active and healthy, making good progress south across the Meridiani plains with a few hiccups along the way. Despite the early end of one autonomous traverse and a Deep Space Network problem that precluded sending commands on sol 364, the rover covered more than 300 meters (984 feet) in the past week, breaking its own one-sol distance records twice! Having scuffed and trenched in the sands of the plain, Opportunity is now examining the trench and nearby soil targets.
Since the Opportunity team was operating in restricted-sol mode, the team chose to plan sols 360 and 361 together as a drive sol followed by a remote-sensing sol. On sol 360, Opportunity traversed a record 154.65 meters (507.4 feet), using a combination of blind drives and auto-navigation software. On the next sol, Opportunity carried out three hours of remote-sensing observations.
Sols 362 and 363 were planned together as another two-sol plan, again with the basic intent of driving as far as possible. After a directed drive of 90 meters (295 feet), the rover turned 180 degrees and continued in auto-navigation mode, resulting in an impressive 156.55-meter (513.6-foot) traverse. That is a new record for a single sol of driving on Mars. Alternating the rover's drive direction is part of the engineering strategy for maintaining the long-term health of our wheel drives. For the second sol of the plan, Opportunity was commanded to continue driving for up to 120 meters (394 feet), as long as no drive errors had occurred on the first sol. However, due to a previously unidentified navigation software vulnerability, the sol 363 drive errored out at its start.
The plan for sol 364 was to continue the series of long traverses south. Unfortunately, there was a problem with a coolant line at a Deep Space Network transmitter, most of the pass was lost, and the plan could not be uplinked in the couple of minutes remaining. So, for what may have been the first time during Opportunity's mission, a sol's worth of nominal activities was lost, and the science run-out sequence from earlier commands was executed instead. Run-out sequences give the rover some useful tasks to do in case it does not get a new set of commands.
On sol 365, Opportunity used its panoramic camera and miniature thermal emission spectrometer to observe a target dubbed "Strange Rock," then moved a few meters (several feet) to get in position for trenching through a dune ripple crest.
For sol 366, rover planners worked very closely with the science team to choreograph a rover trenching dance: Opportunity moved, scuffed (dragging its front wheels backwards multiple times), and finally trenched in the sand, all while placing the rover in a good orientation for later communications. The rover then went into deep sleep in preparation for an early morning photometric observation. Sol 366 ended on Feb. 3.