Mars Polar Lander

Mars Polar Lander (MPL) was a NASA spacecraft launched in 1999 intended to land on Mars, which failed to communicate after landing. It was one of two separately-launched spacecraft in NASA's Mars Surveyor '98 project, the other spacecraft being the Mars Climate Orbiter, which also lost communication, famously after receiving instructions based upon the wrong units. Mars Polar Lander instruments:

• MARDI - Mars Decent Imager.
• SSI - Surface Stereo Imager.
• LIDAR - Light Detection and Ranging (the visible light equivalent of radar).
• RA - Robotic Arm.
• RAC - Robotic Arm Camera.
• MET - Meteorological Package.
• TEGA - Thermal and Evolved Gas Analyzer.
• Mars Microphone.

Mars Polar Lander also carried two identical probes, Deep Space 2 A and B, that were released to impact the surface, to measure descent, impact, soil conductivity, and detect any water. These also communicated nothing.