A National Research Council (NRC) committee has recommended that NASA crash the Galileo spacecraft into Jupiter at the end of its mission to protect Europa and Io from possible contamination by Earth life forms that may be aboard the spacecraft. The recommendation came at the end of a study by the NRC's Space Studies Board's (SSB's) Committee on Planetary and Lunar Exploration (COMPLEX). This recommendation is in agreement with plans already proposed by NASA. According to a letter accompanying the release of its report, the committee "reached a consensus that an appropriate interim course of action is to defer the destruction of Galileo until after the completion of the Io polar flybys, in order to obtain as much science as possible from the mission. "
According to the report's preface, "NASA's Planetary Protection Officer requested that the Space Studies Board undertake a study to evaluate the planetary protection requirements and methods used to prevent contamination of Europa by terrestrial organisms in future orbiter and lander missions and that it recommend any necessary changes." The Galileo mission was considered along side future, yet to be launched missions.
The main issue of concern is the 'forward' contamination of Europa - that is, the possibility that Earth life could make its way to Europa aboard our spacecraft. According to the report "even though current information is not sufficient to conclude whether Europa has an ocean, native life, or environments compatible with terrestrial life, it is also insufficient to dismiss these possibilities at this time. "
As such, the Committee recommended that "future spacecraft missions to Europa must be subject to procedures designed to prevent its contamination by terrestrial organisms. This is necessary to safeguard the scientific integrity of future studies of Europa's biological potential and to protect against potential harm to europan organisms, if they exist, and is mandated by obligations under the United Nations' Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies (U.N. Document No. 6347 January 1967).
Galileo recently left the influence of Jupiter's magentosphere and has begun to move into regions affected directly by the solar wind. Toward the end of the year Galileo and the Saturn-bound Cassini spacecraft will make joint observations of the environment around Jupiter.
° Letter: On Scientific Assessment of Options for the Disposal of the Galileo Spacecraft, National Research Council (NRC)
° Report: Preventing the Forward Contamination of Europa, NRC
° NRC Task Group on Preventing the Forward Contamination of Europa
° Galileo Mission, NASA JPL
° Report: Evaluating the Biological Potential in Samples Returned from Planetary Satellites and Small Solar System Bodies, NRC
° Planetary Protection, SpaceRef Directory
° Planetary Protection, Astrobiology Web
° Bring Em Back Alive-- Or At Least Carefully: Planetary Protection Provisions for Sample Return Missions, Ad Astra Magazine