Key Dates:
- 01.03.99: Launch (20:21:10 UT)
- 12.03.99: Contact Lost (20:00 UT)
- Status: Crashed on Mars
Scientific Instruments:
- MVACS Mars volatile and climate surveyor instrument package
- SSI stereo surface imager
- RA robotic arm
- MET meteorology package
- TEGA thermal and evolved gas analyzer
- RAC robotic arm camera
- MARDI Mars descent imager
- LIDAR light detection and ranging instrument
Mars Polar Lander Mission Information: The Mars Surveyor '98 program is comprised of two spacecraft launched separately, the
Mars Climate Orbiter (formerly the Mars Surveyor '98 Orbiter) and the Mars Polar Lander (formerly the Mars Surveyor '98 Lander). The two missions were designed to study the Martian weather, climate, and water and carbon dioxide budget, in order to understand the reservoirs, behavior, and atmospheric role of volatiles and to search for evidence of long-term and episodic climate changes.
The last telemetry from Mars Polar Lander was sent just prior to atmospheric entry on 3 December 1999. No further signals have been received from the lander, the cause of this loss of communication is not known.
Launched in January 1999, Mars Polar Lander was to be the first-ever landing in the polar regions of Mars, near the southern polar cap. Its primary goal was to deploy a lander and two penetrators (known as Deep Space 2) on the surface of Mars to extend our knowledge on the planet's past and present water resources. The objective was to explore the never-before-studied carbon dioxide icecap about 1,000 kilometers from the south pole.
Two small microprobes - the Deep Space 2 technology mission - hitched a ride to Mars on the Lander, with the goal of penetrating into the Martian subsurface to detect water ice.
Mars Polar Lander and the attached Deep Space 2 probes were launched on a Delta 7425 (a Delta II Lite launch vehicle with four strap-on solid-rocket boosters and a Star 48 (PAM-D) third stage) which placed them into a low-Earth parking orbit. The third stage fired for 88 seconds at 20:57 UT 3 January 1999 to put the spacecraft into a Mars transfer trajectory and the spacecraft and third stage separated at 21:03 UT. Trajectory correction maneuvers were performed on 21 January, 15 March, 1 September, 30 October, and 30 November 1999.
After an 11 month hyperbolic transfer cruise, the Mars Polar Lander reached Mars on 3 December 1999. A final 30 minute tracking session begins at approximately 12:45 UT (7:45 a.m. EST) and was used to determine if a final thruster correction was necessary. Final contact to retrieve data on the status of the propulsion system was made from approximately 19:45 UT to 20:00 UT. At approximately 20:04, 6 minutes before atmospheric entry, an 80 second thruster firing was to turn the craft to its entry orientation. The Star 48 upper cruise stage was to be jettisoned at about 20:05 UT, and about 18 seconds later the microprobes were to be dropped from the cruise stage into the martian atmosphere (also targeted at the southern polar layered terrain). The lander was to make a direct entry into Mars' atmosphere at 6.8 km/s at about 20:10 UT (3:10 p.m. EST). Due to lack of communication, it is not known at this time whether all these steps following final contact were executed, nor whether any of the descent plan described below took place as designed.
The lander would have touched down at approximately 20:15 UT Earth received time (3:15 p.m. EST) in the late southern spring season, during which the Sun will always be above the horizon at the landing site. The other times listed above are also Earth received times, light travel time from Mars at that point was approximately 14 minutes.
Immediately after landing the solar panels were to be deployed. The first signal from the lander was to reach Earth at 20:39 UT (3:39 p.m. EST), but was never received.
An independent investigation into the failure, whose results were released publicly on 28 March 2000, indicated that the most probable cause of the failure was the generation of spurious signals when the lander's legs deployed during the descent. These signals falsely indicated that the spacecraft had touched down on Mars when in fact it was still descending. The main engines prematurely shut down, and the lander fell to the Martian landscape.
