Four drives add to Spirit's progress; Cleaning event boosts energy for Opportunity

First, Spirit completed a science campaign on light-toned material unearthed the preceding week, then the rover resumed driving on Sol 1866 (April 3, 2009; no sol number for Spirit corresponded to April 2, 2009, using the criterion of the date in Los Angeles at local solar noon on Mars). The Sol 1866 drive achieved only about 3 meters (10 feet) of progress due to excessive slip.

On the next drive sol, Sol 1868 (April 5, 2009), Spirit avoided the troubled terrain and completed about 17.5 meters (57 feet). A pair of drives on Sols 1870 and 1871 (April 7 and 8, 2009) added another 20 meters (66 feet) of progress.

As of Sol 1871 (April 8, 2009), Spirit's solar array energy production is 240 watt-hours, equivalent to what it takes to light a 100-watt bulb for 2.4 hours. Atmospheric opacity (tau) has improved slightly to 0.99. The dust factor is 0.304, meaning that 30.4 percent of sunlight hitting the solar array penetrates the layer of accumulated dust on the array. The rover is in good health as it makes progress around Home Plate. Spirit's total odometry is 7,726.78 meters (4.80 miles).

Credit: NASA/JPL-Caltech
High resolution image

Spirit used its navigation camera to take the images combined into this 210-degree view of the rover's surroundings during the 1,861st to 1,863rd Martian days, or sols, of Spirit's surface mission (March 28 to 30, 2009). The center of the scene is toward the south-southwest. East is on the left. West-northwest is on the right. The rover had driven 22.7 meters (74 feet) southwestward on Sol 1861 before beginning to take the frames in this view. The drive brought Spirit past the northwestern corner of Home Plate. In this view, the western edge of Home Plate is on the portion of the horizon farthest to the left. A mound in middle distance near the center of the view is called "Tsiolkovsky" and is about 40 meters (about 130 feet) from the rover's position. This view is presented as a cylindrical projection with geometric seam correction.

Opportunity completed a contact science campaign on an exposed rock outcrop and then resumed driving.

On Sol 1845 (April 2, 2009), the rover's robotic arm (IDD) placed the Mössbauer (MB) spectrometer on the outcrop target "Penrhyn" for a multi-sol integration. On Sol 1850 (April 7, 2009), a temporary stand-down on driving was provisionally lifted and Opportunity resumed driving. The MB was retracted and the arm moved into the driving stow position. Opportunity then drove backward about 62.5 meters (205 feet). Diving backward was a continuation of mitigation techniques used in recent weeks in response to elevated current observed in the right-front wheel. The mitigation also has included resting the drive actuator for several sols, which coincided with the just-completed contact science campaign. The drive went well and the right-front actuator exhibited currents near normal levels, good news.

Opportunity also benefited from a solar array cleaning event which boosted energy levels by about 40 percent, a big increase. Now if only Spirit could get such a cleaning.

As of Sol 1850 (April 7, 2009), Opportunity's solar array energy production has increased to 515 watt-hours. Atmospheric opacity (tau) remains elevated at around 0.95. The dust factor has improved to 0.642, meaning that 64.2 percent of sunlight hitting the solar array penetrates the layer of accumulated dust on the array. The rover is in good health with a rested actuator and extra energy.

As of Sol 1851 (April 8, 2009) Opportunity's total odometry is 15,113.97 meters (9.39 miles).

Source: Jet Propulsion Laboratory
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