14 DAY TRIAL // Martian winter officially starts in August, but the rover mission managers wouldn't want to be caught off guard. The team will use the same winter strategy that has worked last year: placing the rovers on a slope where they will be receiving sufficient solar power.
Right now Spirit studies the Home Plate, "collecting data at a furious rate", as principal investigator Steve Squyres, of Cornell University, New York has said. Scientists don't yet know what the Home Plate is made of. According to Squyres, it could be a volcanic ash deposit, layers of ejecta from impact cratering or material laid down by wind or water. "If you took a poll of the team right now, I think you would find the favored hypothesis is that it's some kind of volcanic ash deposit", he said.
Before sending Spirit to a safe place for the winter the team intends to maneuver the rover on top of Home Plate to gather more data. Then, they will direct the rover toward the McCool Hill. "We're steadily approaching a point where if we don't reach a northern facing slope, we won't be as productive as we'd like," Byron Jones, rover mission manager at NASA's Jet Propulsion Laboratory in Pasadena (JPL), California told New Scientist magazine. This way, they intend to maximize the amount of sunlight falling on the rover's solar panels.
Energy consumption
During one Martian day (a sol = 24 hours and 40 minutes) the rover needs at least 400 watt-hours. Simply to stay alive, it needs around 280 watt-hours. The rest is needed to move around, to work with the robotic arm, and to communicate with the Mars Odyssey spacecraft orbiting Mars. Spirit currently receives from the Sun around 450 watt-hours each sol, but in the last 50 sols the energy has dropped by 100 watt-hours.
How is Opportunity doing?
Opportunity is much closer to Mars' equator so the arrival of winter is less pressing. Right now he receives around 600 watt-hours each sol. Eventually the team will send Opportunity to winter in the Victoria Crater, a large impact crater 2500 to 3000 meters away. The journey to this crater is expected to last around three months.
Photo Credit: Spirit's tracks (NASA/JPL)