Mars Climate Orbiter:
Goals: Mars Climate Orbiter mission was to study Mars from orbit with cameras and atmospheric instruments. It also was designed to serve as a communications relay for the
Mars Polar Lander and
Deep Space 2 probes.
Accomplishments: None. Communications were lost as the spacecraft prepared to enter orbit around Mars. An investigation found the spacecraft burned up in Mars' atmosphere due to a navigation error caused by the failure to translate English units to Metric.
Read More About Mars Climate Orbiter