May 21, 2018

Last week the mission team conducted a successful checkout of the spacecraft’s Medium Gain Antenna (MGA). With this test, all of the spacecraft’s antennas have now been used in flight.

OSIRIS-REx has four antennas for communicating between the spacecraft and Earth. The largest, the High Gain Antenna (HGA), has the highest data rate but has a narrow gain pattern,  meaning that it must be directly pointed at Earth for successful transmission. The MGA has a larger pattern, but a lower data rate. In favorable geometries, it will be used to communicate status telemetry back to Earth during the sampling maneuver. The two Low Gain Antennas (LGAs) provide near complete coverage and very low data rate communications. The LGAs are especially useful for transmitting progress telemetry during events, such as maneuvers, when the spacecraft’s other antennas aren’t facing Earth.