Mars rovers Spirit and Opportunity just hanging out and taking pictures for the winter

Still remember the rovers? They were supposed to have lasted for a total of some 90 days back in early 2004 when they landed. Now it's summer 2008, winter on Mars, and they're still hanging out and doing things. Because it's cold and the sun is weak right now they're biding their time and doing what they can when they have the power. First Spirit:

Spirit continues to ride out the Martian winter by doing minimal activities to conserve power. The rover conducts very light science activities every three to four Martian days, or sols, and relays data to NASA's Odyssey orbiter for transmission to Earth every 4 sols. The rest of the time, Spirit mostly sleeps.

Spirit is healthy and all subsystems were performing as expected as of the Odyssey downlink on sol 1598 (July 1, 2008). Solar-array energy has been steady within the range of 225 watt-hours to 230 watt-hours (100 watt-hours is the amount of energy needed to light a 100-watt bulb for one hour).

Then Opportunity:

Opportunity has completed work on the stand-off portion of the full-color panorama of the layered cliff known as "Cape Verde." It may take a couple of weeks for the entire panorama to arrive on Earth, depending on the volume of data the rover is able to transmit during communications links.

Next, Opportunity will move closer to Cape Verde to take a high-resolution image of a smaller area in front of the rover.

During the past week, engineers characterized the performance of the rover's rock abrasion tool along the z-axis by comparing voltage and the speed of the actuator at different temperatures. In the event that the z-axis encoder lines break, as have the encoder lines for the rotate and revolve axes, this characterization will be essential in developing a functional strategy for operating the rock abrasion tool with full, open-loop control. The z-axis encoder is responsible for moving the cutting head outward into the rock.

Next week's plans call for Opportunity to bump forward to a point only a few meters away from the cliff face to take high-resolution images. If possible, Opportunity will also conduct scientific studies of an outcrop target called "Nevada" (so named because of a rock next to it which has a shape reminiscent of the outline of the state of Nevada) using instruments on the robotic arm.

Opportunity is healthy and all subsystems are performing as expected. Energy is around 376 watt-hours (100 watt-hours is the amount of energy required to light a 100-watt bulb for one hour). As of Sol 1578 (July 2, 2008), Tau (a measure of darkness due to atmospheric dust) was at 0.413 and the dust factor (a measure of the proportion of sunlight penetrating dust on the solar arrays) was at 0.771.