Mars Polar Lander Mission Overview

Mars Polar Lander Mission

Mission Overview Launch Jan 3, 1999 Cruise Jan 3, 1999 - Dec 3, 1999 Mars Landing Dec 3, 1999 Landed Operations Dec 3, 1999 - Mar 1, 2000

The Mars Polar Lander was launched on a Delta 7425 in January 1999, and will arrive at Mars in December 1999. Burnout of the 3rd stage was followed by yo-yo despin of the entire stack, followed by spacecraft separation. At this point both the spacecraft and upper stage will have been injected onto a Type 2 trajectory whose aimpoint is biased away from the nominal entry aimpoint, to assure that the upper stage won't impact Mars, as required by Planetary Protection regulations.

After separation, the solar panels will be deployed and pointed to the sun, and initial acquisition will be achieved by the DSN. Throughout cruise, contact will be maintained via the Medium Gain Antenna, and the solar panels pointed at the sun [with a small offset in inner cruise]. Approximately 15 days after launch, the largest Trajectory Correction Maneuver [TCM] will be executed. This maneuver will remove launch vehicle injection errors and the spacecraft's injection aimpoint bias. Depending on the size of the maneuver, it may be necessary to divide this into two smaller maneuvers. Provisions have been made to execute up to 4 additional small TCM's during the remainder of cruise, including one 7 hours prior to entry for final control of the entry angle and landing footprint. Precision approach navigation will be effected via near simultaneous tracking of the approaching Lander and an orbiter at Mars (either the Mars Climate Orbiter or Mars Global Surveyor).

After a direct atmospheric entry, the Lander will be slowed by a Mars Pathfinder-heritage aeroshell and parachute, and a controlled propulsive landing effected. For launch during the Lander's primary launch period, landing will occur between 75 and 78S, on the southern polar layered terrain. The first landed day's activities will include deployment of the solar panels, functional checkout, and establishment of communication with the Orbiter and time critical science activities. Routine science activities will commence on the second day following landing. The Lander will be equipped with a UHF relay for downlink via the Mars Climate Orbiter and/or MGS, and command uplink via the Mars Climate Orbiter. A direct to Earth (DTE) link will also be available for Lander commanding and as a backup downlink. The Lander will carry the Mars Volatiles and Climate Surveyor (MVACS) instrument suite, which will perform in situ investigations to address the science theme "Volatiles and Climate History" on Mars. The Lander will also provide descent imaging with the Mars Descent Imager (MARDI), and accommodate a Light Dectection And Ranging (LIDAR) instrument supplied by the Russian Space Agency. The Lander will search for near-surface ice and possible surficial records of cyclic climate change, and characterize physical processes key to the seasonal cycles of water, carbon dioxide and of dust on Mars. The duration of the landed science phase is expected to last no more than approximately 90 days.

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