Mars Polar Lander/Deep Space 2

Mars Polar Lander was an ambitious mission to set a spacecraft down on the frigid terrain near the edge of Mars' south polar cap and dig for water ice with a robotic arm. Piggybacking on the lander were two small probes called Deep Space 2 designed to impact the Martian surface to test new technologies.
Mars Polar Lander and Deep Space 2 were lost at arrival December 3, 1999.