Mars Polar Lander Mission Status December 15, 1999

Flight controllers for Mars Polar Lander have continued their attempts to communicate with the spacecraft so that they can be certain they
have exhausted all possibilities before they conclude their search. While a recovery is still a possibility, the likelihood of hearing from the
lander is considered remote at this point.

The communication strategy in the coming week is based on the assumption that the clock on the spacecraft was reset. Commands will be
transmitted to the spacecraft in the blind to initialize the clock. It will be assumed the spacecraft received the commands, and flight
controllers will then proceed to command the spacecraft to turn on its UHF antenna. The 150-ft (45.7 meter) antenna at Stanford will then
listen for the lander’s UHF signal. If no signal is heard, then commands will be transmitted to the spacecraft to perform a number of “big
sweeps” during which the lander uses its steerable medium-gain antenna to scan across the sky. Presumably, it would eventually scan
across the area where Earth is and its carrier wave signal would be heard by the Deep Space Network.

In parallel with the communications attempts, the Mars Global Surveyor (MGS) spacecraft will start taking high-resolution images of the
landing site to search for signs of the lander. The search area that the orbiter will be looking at is an ellipse roughly 20 km x 10 km. The
orbiter may be able to spot the parachute or the shadow of the lander. Mars Global Surveyor will start imaging early Thursday morning
(December 16), and it will take about 2 weeks to cover the search area with its high-resolution camera.