A review of the approach of NASA projects to planetary protection compliance

The approaches to planetary protection compliance by several space projects in the period between Galileo and the present are reviewed. The emphasis is on missions to Mars, based on the historical record and the specificity of planetary protection requirements for that planet. However, an interesting change in requirements dating back to Galileo's launch led many years later to the protection of Europa and the choice of ending the mission with an entry into Jupiter. An analogy exists for Cassini at Saturn, with the potential for protecting Titan from the orbiter (not the Huygens probe of course). The Mars missions in the period include successes and failures. Planetary protection implementation is discussed for Mars observer, Mars pathfinder, Mars global surveyor, Mars polar lander, Mars climate orbiter, Mars odyssey, and Mars exploration rover. Next, some recent developments in planetary protection implementation for spacecraft being prepared for launch are presented. Finally, new planetary protection requirements adopted by COSPAR, which NASA is expected to follow, are described.