Progress on antenna actuator; Milestone 11

Spirit is recovering from the high-gain antenna (HGA) anomaly that occurred on Sol 2027 (Sept. 15, 2009).

The HGA problem is suspected to be an apparent intermittent behavior in the dynamic brake relay for the HGA actuators, a problem that has been seen and mitigated before in other rover actuators. Diagnostics were run on the HGA and each actuator moved freely in both directions without problems with the dynamic brake behaving normally.

The challenge for the rover team has been trying to uplink HGA recovery sequences over the low-gain antenna (LGA). Data rates over the LGA are so low that there is often insufficient time in the uplink window to get up all the necessary commands. Because of that, the project is using forward link UHF relay commanding through Mars Odyssey. The forward link has the additional complication that there is additional latency in getting the commands to the rover, so the pace of recovery is impacted. Return to normal HGA usage for Spirit is anticipated by next week. Spirit is otherwise in good health.

As of Sol 2033 (Sept. 21, 2009), Spirit's solar-array energy production was 418 watt-hours with an atmospheric opacity (tau) of 0.972 and a dust factor of 0.626. Total odometry remains at 7,729.93 meters (4.80 miles).

Opportunity has driven four out of the last six sols, making way to Endeavour crater.

On sols 2009, 2011, 2013 and 2014 (Sept. 18, 20, 22 and 23), the rover drove 55 meters (180 feet), 71 meters (233 feet), 70 meters (230 feet) and 59 meters (194 feet), respectively, passing 11 miles of total odometry. Each drive was backwards heading to the west to avoid a large region of potentially risky dune ripples. Eventually, the rover will turn south, then east, to head to Endeavour.

Motor currents in the right-front wheel remain well behaved.

As of Sol 2014 (Sept. 23, 2009), Opportunity's solar-array energy production is 477 watt-hours. Atmospheric opacity (tau) is 0.681, and the dust factor on the solar array is 0.603. Total odometry is 17,717.33 meters (11.01 miles).

 

Source: Jet Propulsion Laboratory
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