On Sept. 27, 1997, NASA's Mars Pathfinder mission beamed its very last data transmission back to Earth.br br The Mars Pathfinder mission consisted of a base station and the very first Mars rover named Sojourner. Pathfinder was three months in to what was supposed to be just a one-month mission when the base station's battery began to fail. NASA struggled to reestablish contact with Pathfinder for another five months before giving up and calling the mission complete.