Mission Timeline: Rover Egress

The rover egress phase is defined as the period of time following placement of the rover into a "safe state" after landing to driving the rover off of the lander onto the Martian surface.

The egress phase will likely last through Sol 4 or 5 (the landing sol is designated Sol 1). The major deployment and egress activities are power intensive, and must occur during the martian day when the solar arrays can charge the rover battery, and when the rover and the landing site are naturally illuminated. The actual rate for egress activities is largely dictated by the availability of power, the duration and number of ground decision points, and the availability of a communications link.

The lander has no further function or capability after egress is complete, so there will be no pictures of the rovers themselves in operation (in contrast to the Mars Pathfinder lander, which was active and imaged the rover Sojourner throughout its surface operations). Pictures taken from the Mars Exploration Rover will be rather like those you might take from the inside of your car, as we´ll see parts of the Rover in each picture.

Egress consists of a carefully choreographed series of steps by the rover; each initiated by the ground only after verification that the previous step has been successfully executed. Because there is limited knowledge of the terrain at the landing sites before the rovers arive, the flight team must interactively assess the rover data, command the rover, and then assess the resulting data before proceeding to subsequent steps. Consequently, many possible egress scenarios exist that depend on the outcome of the events leading up to egress.

The principal steps during this phase include:

• deployment of the Pancam mast and the high-gain antenna
• characterization of the lander, the landing site, and the surrounding terrain
• rover stand up
• calibration of science instruments
• selection of a suitable egress path
• egress from the lander onto the martian surface