Without parachutes or braking rockets, the tiny Deep Space 2 probes should reach the Martian surface at about the same time as the lander. The force of their 400 mph impact should drive a 4.2-inch long penetrator up to three feet into the soil with instruments of their own to search for water. But to make progress you must be bold. The smaller probes are predicted to impact about 35 miles northwest of the larger Polar Lander and about one mile from one another. Relying on sharp images of the planet gathered by NASA's already orbiting Mars Global Surveyor spacecraft, scientists and engineers have selected a gracefully rolling patch of terrain nearly devoid of rocks as the landing site.
Scientists anticipate a terrain with a consistency of coffee grounds, though frozen.
Though it's late spring in the region, the temperatures will be 200 degrees below zero. Winds of 4 mph are forecast, varying from south to east. On the eve of the Polar Lander's arrival, flight control teams and scientists at NASA's Jet Propulsion Laboratory were optimistic they will succeed and were eager to put the Sept. 23 loss of their Mars Climate Orbiter behind them. Climate Orbiter was lost as it maneuvered into orbit around the Red Planet after a near 10-month transit from Earth. Early today, navigation and flight control managers will gather to assess the need for pre-descent maneuvering to hone the trajectory.