The first drive phase is defined as the period of time after landing during which engineers first conduct tests to ensure the rover is in a "safe state" and then move it for the first time beyond its original landing zone.
After entry, descent, and landing, the Mars Science Laboratory rover ventured forth on its first drive on Aug. 22, 2012, going forward about 15 feet (4.5 meters), rotating 120 degrees and then reversing about 8 feet (2.5 meters). Before making that first drive, mission controllers on Earth needed to make sure the surface directly beneath the rover's wheels did not present an immediate hazard. They also needed to complete deployment of the mast, the High Gain Antenna, the sampling system, test communications links, and make a few other checks before putting the proverbial "pedal to the metal." (Unlike prior rover missions, however, the Mars Science Laboratory rover did not have a lander from which to egress. Instead, its mobility system--that is, its wheels and related parts--was fully deployed prior to landing.)
One of the greatest concerns post-landing is rover stability. Even though the rover can handle steep cliffs of up to 50 degrees and has a ground clearance of 60 centimeters (almost 2 feet), it's not possible to predict down to the last inch where the spacecraft will land. If the rover had ended up, say, with one wheel on top of a rock and the others on a slope, engineers would want to know about it and make sure the rover could maneuver successfully to a safer position.
Upon landing, the Mars Science Laboratory rover completed a series of automated computer sequences to make sure all systems were operating as expected and to check the immediate environment. Such activities include, for example:
After all of these tasks were completed, the rover made its first drive from the landing zone onto uncharted Martian terrain. The rover tests the many science instruments on board as exploration gets under way.