The Mars Telecommunication Orbiter will be the first interplanetary spacecraft whose main mission is to provide communications services to other missions. It will orbit Mars at a higher altitude than most orbiters, about 2,800 miles above the Martian surface. This will provide an enhanced line of site to Earth. The spacecraft will communicate with Earth via two radio bands and a new optical communications terminal, which will demonstrate the use of a near-infrared laser beam for interplanetary communications.

Information from the spacecraft will be beamed to the 5-meter Hale Telescope at the Palomar Observatory in California. Optical communication provides the potential for transmission speeds that are orders of magnitude better than those currently available.

The need for enhanced communications between the planets was anticipated early on by science fiction writers. George O. Smith, in his 1942 novella QRM - Interplanetary, writes about the work of the United States Army Signal Corps in creating a series of interlinked telecommunication stations around the inner solar system. The system for Venus worked as follows:

The [signal] was hurled at the sky out of a reflector antenna by a thousand-kilowatt transmitter. The wave seared against the Venusian Heaviside Layer... [it] emerged ... as a weak, piffling signal...

... weak and as wobbly as it was, was taken in by eager receptors... it was dehashed, destaticked and deloused [and] was hurled out on a tight beam from a gigantic parabolic reflector.

Across sixty-seven million miles of space went the signal. Across the orbit of Venus it went in a vast chord, and arrived at the Venus Equilateral Station... beams from Venus Equilateral were directed at Mars and Terra...
(Read more about the Venus Equilateral Relay Station)

The Venus Equilateral Station occupied one of the Trojan points sixty degrees ahead of Venus; it was an enormous space station three miles long and one mile in diameter, spun for gravity, and home to 2600 people. Writing in 1976, Arthur C. Clarke said that George O. Smith was "probably the first writer - certainly the first technically qualified writer - to spell out the uses of space stations for space communications. George Smith, I'm sure, correctly anticipates the future."

The more modest Mars Telecommunications Orbiter is expected to transmit data at a rate of 1 megabit per second when Mars is furthest from Earth and reception takes place during the day. When Mars is at its closest approach and reception takes place at night, data transmission rates of 10-30 megabits per second are expected. In contrast, NASA's Mars Odyssey orbiter transmits data at about 128,000 bits per second, about twice as fast as a dial-up connection.