Replenishing the Mars relay network

Over the past decade, several NASA Mars orbiters - Mars Global Surveyor, 2001 Mars Odyssey, and the Mars Reconnaissance Orbiter - along with ESA's Mars Express orbiter, have provided telecommunications relay services to a series of Mars landers, including the Mars Exploration Rovers (Spirit and Opportunity), the Phoenix Lander, and the Mars Science Laboratory's Curiosity Rover. For each of these missions, relay communications has demonstrated significant benefits, including greatly increased data return from the Martian surface, reduced energy-per-bit cost of communication, and capture of high-rate critical event engineering telemetry during entry, descent, and landing. The orbiters in this relay network, however, are operating well beyond their original design lifetime. To replenish this aging infrastructure, two additional science/relay orbiters are slated for launch in this decade, both equipped with Electra UHF relay transceivers with the plan to provide relay services in addition to each mission's primary science objectives. On November 18, 2013, NASA successfully launched the Mars Atmosphere and Volatile Evolution Mission (MAVEN). And in January 2016, ESA plans to launch the ExoMars/Trace Gas Orbiter mission, with redundant Electra payloads provided by NASA. Key aspects of each mission relating to its relay service characteristics will be reviewed.