Resolving the Cassini/Huygens relay radio anomaly

NASA's Cassini mission to Saturn carries the European Space Agency's (ESA's) Huygens probe, which it will release shortly before an encounter with Saturn's moon, Titan, a possible location for extraterrestrial life within our Solar System. As it parachutes towards Titan's surface, Huygens will acquire scientific information which will be relayed to Earth through Cassini. Comprehensive testing of this relay radio link was not performed prior to Cassini launch and cannot be done during cruise. A test using NASA's Deep Space Network (DSN) to mimic the probe's signal was performed in 2000 and uncovered an anomaly that, unchecked, would result in nearly complete loss of the Huygens mission. An international team of experts from NASA and ESA was assembled to solve this problem: the Huygens Recovery Task Force (HRTF.) This team, co-chaired by the author, performed extensive testing, modeling, and simulation to understand the failure mechanism. Each Huygens science team determined mission impacts for various scenarios based on these results. This led to a suggested modification to the Cassini trajectory that will result in nearly complete data return for Huygens with minimal impact on Cassini.