LOS ANGELES: Scientists at the Jet Propulsion Laboratory lost contact with the Pathfinder lander today after a computer aboard the spacecraft inexplicably reset itself as it was sending back pictures. The second such instance in three days had researchers scrambling for a solution even as JPL tried to reestablish contact with the lander. Engineers, who expect to fix the software problem overnight, report that the mission is proceeding normally in other respects. Sojourner's batteries appear to be functioning well even in Martian temperatures that swing wildly from -8°F to -130°F. Still, the rover has already surpassed the seven days it was designed to function, and every day from now on is borrowed time.