in an ambitious revival of exploration of Mars, two us spacecraft have approached the planet. One spacecraft has studied the atmosphere, prospects of water and observed weather through the seasons of a full Martian year (687 days). The second craft is on course for a landing on December 3 at the edge of the south polar ice cap, where the terrain holds a layered record of the climate history of the planet.

Mission officials at the Jet Propulsion Laboratory in Pasadena, California, said that both spacecraft, Mars Climate Orbiter and Mars Polar Lander, are in excellent condition. Though relatively modest in cost and scope, the missions are integral steps in a long-term strategy of sending small spacecraft to Mars at each 26-month opportunity when the orbital relationship is right.