The primary science phase began when the orbiter entered its science orbit and its instruments and other systems were checked out, calibrated, and ready to collect science data. The primary science phase will last for at least one Mars year (about two Earth years), beginning after the end of solar conjunction in November, 2006 and ending with the start of solar conjunction in November, 2008. Solar conjunction occurs when the sun comes between the Earth and Mars, temporarily limiting communications.
During this phase, science observations are more complex than on previous Mars missions, because Mars Reconnaissance Orbiter coordinates three basic observation goals:
Targeted observations often involve nearly simultaneous, coordinated observations by more than one instrument.
By mid-March 2008, with the support of two 34-meter (112-foot) Deep Space Network Deep Space Network antennas each day of the primary science phase, the project had returned more than 50 Terabits of science data, more data than all previous planetary missions combined.
Toward the end of the primary science phase, other Mars missions launched in 2007 will begin to arrive. Mars Reconnaissance Orbiter will use its Electra UHF radio to provide for any navigation, command, and telemetry needs these missions may have. While the primary science phase is planned to end after one Mars year, NASA may choose to approve continuation of science observations beyond the primary science phase until end of the relay phase.