Spirit Makes Tracks on Mars
Pasadena, Spirit Mission Sol 12
Spirit is on the surface of Mars. At about half past midnight PST on Thursday, January 15, NASA engineers sent the command ordering Spirit to roll forward off its landing platform onto the soil of the red planet.
|This image from the Mars Exploration Rover Spirit’s rear hazard identification camera shows the rover’s hind view of the lander platform, its nest for the past 12 sols, or martian days. The rover is approximately 1 meter (3 feet) in front of the airbag-cushioned lander, facing northwest. Note the tracks left in the martian soil by the rovers’ wheels, all six of which have rolled off the lander. This is the first time the rover has touched martian soil.
It was a journey of only 3 meters (10 feet), but it was perhaps the most significant step the rover will take during its 3-month mission.
"We have six wheels in the dirt. Mars is now our sandbox, and we are ready to play and learn," said Dr. Charles Elachi, director of the Jet Propulsion Laboratory in Pasadena, CA.
An hour and a half later, Spirit sent back the first images of its new surroundings, confirming that it had succeeded in its task. The images were taken by Spirit’s Hazcams (hazard-avoidance cameras).
The rear-facing Hazcam image clearly showed the rover’s tracks in the martian soil, with the lander in the background.
The Hazcams are pairs of low-resolution cameras mounted below the rover’s solar panels, one pair in front and one in the rear. They image the ground immediately around the rover and help it avoid surface features that could damage the vehicle during automatic navigation.
For the past several sols, Spirit has executed a series of turning maneuvers, rotating in place clockwise about 1/3 of the way around. Engineers chose to have Spirit leave the lander in this direction because the forward pathway was partially blocked by a piece of the lander’s airbag that they were unable to retract fully.
Spirit’s first task, now that it is on the surface, will be to try out the scientific instruments on its IDD (instrument deployment device). The rover will do this by examining the pebbly surface material, a mix of soil and small rocks, in the region immediately in front of it.
After that, scientists are eager to learn more about the rocks and soil independently of each other. They will start with a rock, most likely a nearby triangular-shaped rock that has been tentatively dubbed "Pyramid." Spirit will spend several sols examining Pyramid in detail.
The current plan calls for Spirit then to move on to Sleepy Hollow, a small nearby depression filled with fine-grained soil.
The science team hopes the rover will reach Sleepy Hollow by sol 20, because Opportunity is scheduled to land on the following sol. While Opportunity is landing and completing its initial deployment, the engineering team will be focused on ensuring Opportunity’s success. During that time, a period of 3 sols, Spirit will remain in place and execute a preset sequence of science-oriented commands.
Now that Spirit is on the surface, engineers expect to reap a side benefit: increased communication capability. Each sol, the rover gets two chances to send data to each of the NASA spacecraft orbiting Mars, Mars Global Surveyor (MGS) and Mars Odyssey. The orbiters then relay the information back to Earth.
While the rover was still on its lander, however, mission engineers opted to skip one of the two daily chances to communicate via MGS. They found that the rover got too warm when they used every available communications window.
The engineers’ expect Spirit to remain cooler now that it’s on the ground, so they hope to be able to take advantage of both of the MGS data-transmission opportunities each day. Doing so will increase the total amount of scientific information Spirit can return.