The following missions have been, are, or will be subject to planetary protection requirements. To search all NASA missions, visit here.
- Missions Currently in Operation
- Past Missions
- Missions in Development or Under Study
Planetary protection procedures are now being employed at sites worldwide where solar system exploration spacecraft are being assembled or prepared for launch. As solar system exploration advances, scientists are learning more about extraterrestrial environments where life might possibly thrive. And on Earth, scientists are continuing to explore more and more extreme environments looking for life, and finding it virtually everywhere. Definition and execution of planetary protection requirements thus grows more complex as knowledge of solar system bodies grows and understanding of boundary conditions for terrestrial life expands. In addition, the increasing sensitivity of equipment and experiments designed to search for evidence of past or present biological activity on other solar system bodies requires greater attention to detection and control of biological and even nonbiological organic contamination on spacecraft components, to ensure that science investigations are not compromised.
Planetary protection requirements are established for solar system exploration missions by considering mission types, targets, and goals. The NASA Planetary Protection Officer determines specific requirements for individual missions in accordance with NASA policy, policy guidelines of the Committee on Space Research as accepted by NASA, and in consultation with the National Research Council’s Space Studies Board. No planetary protection requirements are imposed on missions to the Sun, Mercury and Earth’s Moon – classified Category I for planetary protection purposes – because biological contamination of these bodies is not considered a risk, given their extreme environmental conditions. None of the more than 2,000 samples of lunar material brought back to Earth by six Apollo missions has yielded evidence of past or present lunar biological activity. Consequently missions to and from the Moon are not required to have formal planetary protection plans in place.
Category II missions, such as the Galileo orbiter mission to Jupiter and the Cassini orbiter mission to Saturn, must provide only documentation of missions preparations and operations to the Planetary Protection Officer. Category II missions are expected to minimize the likelihood of accdental impact with their target planets. Category II probes and landers, such as the Huygens probe to Saturn’s moon Titan, may require some contamination control measures.
Planetary protection requirements are established for missions to Mars and other bodies of inerest to studies of the origin of life, and which may be contaminated, according to type of mission and destination.
Orbiter and flyby missions – Category III – are generally required to employ passive biological contamination controls. Planetary protection requirements for NASA’s Mars Global Surveyor, Mars Odyssey, and Mars Reconnaissance Orbiter spacecraft, for example, are intended to ensure that these orbiters do not inadvertently leave orbit and inadvertently impact a target body during their missions or after their missions are completed.
Category IV planetary protection requirements for lander and rover missions vary in stringency depending on whether the spacecraft will be exploring areas of astrobiological interest. For Mars, Category IV is divided into three subcategories, defined by the nature of mission. Planetary protection requirements for NASA’s Mars Exploration Rovers, for example, are intended to ensure that these spacecraft do not transport Earth microbes to the surface of Mars in sufficient number to cause either biological or organic contamination.
