The Mars Climate Orbiter spacecraft would carry out research on Mars into the atmospheric conditions on the planet and their effects.

To carry out the measurements and observations, the spacecraft was equipped with a pressure-modulated infrared radiometer and a Mars Colour Imager. The Mars Climate Orbiter probe was launched on 11 December. Two different teams worked simultaneously on the project from different locations.

When the planned orbital insertion manoeuvre began, the Mars Climate Orbiter lost radio contact with the spacecraft as it passed behind Mars, 49 seconds earlier than expected. Communication was never re-established. This could happen because one NASA team was using imperial units, while another was using metric units for an important space operation. This is how the Mars Climate Orbiter was lost.