Communications with Earth Mars Reconnaissance Orbiter
communicates with the Deep Space Network antennas on Earth using
two different kinds of radio waves: From the viewpoint of a Deep
Space Network antenna on Earth, the orbiter spends about one-
third of its time behind Mars during each orbit. During these
times, the orbiter is "occulted from the Earth." During
occultations, Mars Reconnaissance Orbiter cannot usefully send
or receive radio signals. So, out of 16 hours of daily Deep
Space Network tracking, Mars Reconnaissance Orbiter sends data
to Earth for 10 to 11 hours, and does that for about 700 days.
The data rate is about 0.5 to 4 megabits per second. With these
figures in mind, the estimated volume of data returned by Mars
Reconnaissance Orbit was predicted to be about 34 terabits. In
fact, the spacecraft has already returned more than 50 terabits
of data -- more data than all previous planetary missions
combined.