As our ability to explore Mars increases, we need to create a capable communications system that will support global reconnaissance of the planet. This infrastructure will also relay back to Earth the vast amounts of information gathered through surface exploration, sample return missions, robotic outposts and even eventual human exploration.

Each future science orbiter, including the Mars Reconnaissance Orbiter, will continue to carry a proximity communications system for relaying information from surface and aerial vehicles. Science orbiters, however, typically orbit as close as possible to Mars, receiving communication from surface vehicles in brief spurts only when passing rapidly across the sky. To provide more constant relays, a dedicated communications orbiter is being jointly planned by NASA and the Italian Space Agency to orbit at several thousand kilometers altitude in 2007.

Each science and communications orbiter can also be used to accurately determine the position and velocity of spacecraft approaching Mars, landers descending to the surface and vehicles moving around on the surface and in the atmosphere. Advances in radio navigation are needed to fully exploit the potential for in situ exploration of Mars.

Technologies needed for Mars exploration include higher frequency K band radios for communications between orbiters, large landed assets and Earth. Lightweight antennas are also needed for improving communication rates. Further down the road, optical communications offer the potential for very high data rates using compact communications packages.

As the number of assets on the Mars surface grows, we anticipate communications would occur using an Internet Protocol similar to the one we have now on Earth. Achievement of this goal would mean the establishment of the first Interplanetary Internet!