PASADENA: The National Aeronautics and Space Administration has announced plans to send an unmanned "rover" to Mars at the end of the year, the first sign of NASA's interest in the Red Planet since it lost contact with its billion-dollar Observer spaceship in 1993. NASA plans to launch its Pathfinder mission next December 2, 1996. If it lands on Mars as planned on July 4, 1997, it would be the first time since two Viking missions landed there in 1976. "Mars has always had this romantic hold on us," says TIME aerospace correspondent Jerry Hannifin. "It's one of the brightest stars in the sky and has been the subject of speculation about life there for many years. We know, for instance, that there is enough moisture there to have ice deposits on its north and south poles and temperatures, though very cold, somewhat similar to those on earth. And you can see canyons on its surface, 50 times deeper than our own Grand Canyon, where water obviously flowed. The question is, What happened? What sort of catastrophic event finished life on that planet?" The remote-controlled Soujourner rover, no bigger than a microwave oven, will roll out of the Pathfinder lander on six wheels and roam the planet inspecting rocks and weather for up to 30 days. The Smithsonian Institution in Washington plans to issue a daily Martian weather report.