The Optical Navigation Camera was tested for improved navigation capability for future missions. Similar cameras on orbiters of the future will be able to serve as high-precision interplanetary "eyes" to guide incoming spacecraft as they near Mars.
From 30 days to 2 days prior to Mars Orbit Insertion, the spacecraft collected a series of images of Mars' moons Phobos and Deimos. By comparing the observed position of the moons to their predicted positions relative to the background stars, the mission team was able to accurately determine the position of the orbiter in relation to Mars.
While not needed by Mars Reconnaissance Orbiter to navigate to Mars, the data from this experiment demonstrated that the technique could be used by future spacecraft to ensure their accurate arrival. Accuracy will be important to future landers and rovers in need of extremely precise navigation to safely reach their landing sites.