The rover's antennas

The Mars Science Laboratory will have both a low-gain and high-gain antenna that will serve as both its "voice" and its "ears." They will be located on the rover equipment deck (its "back").

The low-gain antenna sends and receives information in every direction; that is, it is "omni-directional." The antenna transmits radio waves at a low rate to the Deep Space Network (DSN) antennas on Earth. The high-gain antenna can send a "beam" of information in a specific direction and it is steerable, so the antenna can move to point itself directly to any antenna on Earth. The benefit of having a steerable antenna is that the entire rover doesn't necessarily have to change positions to talk to Earth. Like turning your neck to talk to someone beside you rather than turning your entire body, the rover can save energy by moving only the antenna.

Not only will the rover be able to send messages directly to Earth, but it will also be able to uplink information to other spacecraft orbiting Mars, utilizing mainly the Mars Reconnaissance Orbiter as a messenger who can pass along news to Earth for the Mars-bound rover. The orbiter can also send messages to the rover.

The benefits of using the orbiting spacecraft are that the orbiters are closer to the rover than the Deep Space Network antennas on Earth and the orbiters have Earth in their field of view for much longer time periods than the rover on the ground.

The radio waves to and from the rover are sent through the orbiters using UHF antennas, which are close-range antennas which are like walky-talkies compared to the long range of the low-gain and high-gain antennas. One UHF antenna will be located on the rover.