Abstract Perched in the nose of a Delta rocket, one of the simplest satellites ever built by the U.S. roared off the launch pad at Vandenberg Air Force Base last week be begin an 8 million-year journey in space. ...Bcause LAGEOS is expected to remain in orbit for so long, NASA has placed aboard it two stainless-steel sheets each etched with a message conceived by astrophysicist Carl Sagan of Cornell University , designed to inform extraterrestrial visitors or future inhabitants of the earth about the...