Communications With Earth Summary

Mars Reconnaissance Orbiter communicates with the Deep Space Network antennas on Earth using two different kinds of radio waves:

	X-band:		the current standard in communications, which, when amplified, allows the orbiter to send data back to Earth more than 10 times faster than previous missions.
	Ka-band:		a previously untested radio frequency four times higher than X-band, which allows scientists to bring data back even faster.

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.