In 2003, with Mars closer to Earth than it had been in 60,000 years, scientists launched three life-seeking planetary landers. If the long journeys prove successful, all should be hard at work on the Red Planet's surface by January 2004. NASA's Spirit and Opportunity and the European Space Agency's Beagle 2 represent the pinnacle in the history of the search for extraterrestrial life. Leading scientists, who believe life may exist beyond Earth, explain skepticism about ETs having visited Earth.
