In 1967, the United States strengthened its commitment and leadership on planetary protection by negotiating, and becoming a state party to, the Outer Space Treaty. By ratifying this treaty, the United States accepted its obligations as legally binding under international law, and the treaty became the “law of the land” under the Constitution. The planetary protection obligations in the Outer Space Treaty appear in Article IX as follows:
In the exploration and use of outer space, including the Moon and other celestial bodies, States Parties to the Treaty shall be guided by the principle of co-operation and mutual assistance and shall conduct all their activities in outer space, including the Moon and other celestial bodies, with due regard to the corresponding interests of all other States Parties to the Treaty. States Parties to the Treaty shall pursue studies of outer space, including the Moon and other celestial bodies, and conduct exploration of them so as to avoid their harmful contamination and also adverse changes in the environment of the Earth resulting from the introduction of extraterrestrial matter and, where necessary, shall adopt appropriate measures for this purpose. If a State Party to the Treaty has reason to believe that an activity or experiment planned by it or its nationals in outer space, including the Moon and other celestial bodies, would cause potentially harmful interference with activities of other States Parties in the peaceful exploration and use of outer space, including the Moon and other celestial bodies, it shall undertake appropriate international consultations before proceeding with any such activity or experiment. A State Party to the Treaty which has reason to believe that an activity or experiment planned by another State Party in outer space, including the Moon and other celestial bodies, would cause potentially harmful interference with activities in the peaceful exploration and use of outer space, including the Moon and other celestial bodies, may request consultation concerning the activity or experiment.1
Thus, the United States is obligated to develop policies, processes, and measures to avoid forward contamination of both the Moon2 and other extraterrestrial bodies and adverse effects of back-contamination of Earth’s biosphere by both government and non-governmental interplanetary missions. Under these requirements, the United States is responsible for the collection, transport, containment, and biological and biohazard testing of extraterrestrial material brought back to Earth by space exploration missions subject to its jurisdiction.3
1 Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies, opened for signature Jan. 27, 1967, 18 U.S.T. 2410, 610 U.N.T.S. 205 (hereinafter Outer Space Treaty).
2 The Moon is included here not because of any concern about indigenous life but because planetary protection policies are also concerned with environments likely to be relevant to studies of prebiotic chemical evolution. The ices deposited in permanently shaded regions near the lunar poles are believed to record significant information about the flux of volatiles through cislunar space throughout the history of the solar system. See, for example, National Research Council, Exploring Organic Environments in the Solar System, The National Academies Press, Washington, D.C., 2007, p. 87.
3 In its final report, the committee will address the Outer Space Treaty’s role in planetary protection policies in more detail.
As a leading spacefaring nation, the United States has played an important role in developing a national approache that complies with the Outer Space Treaty’s provisions on planetary protection. The scientific basis of U.S. government planetary protection policies has largely stemmed from five decades of studies by and recommendations from the SSB. At the national level, the United States has made planetary protection an important factor in NASA policy, the design and execution of NASA’s missions, U.S. government interagency processes, cooperation with non-governmental experts and groups, and U.S. diplomatic cooperation with other countries. Internationally, the United States has helped develop harmonized, science-based standards in COSPAR. Although COSPAR documents are not legally binding, they are persuasive, and the United States has applied COSPAR recommendations in fulfilling its planetary protection obligations under the Outer Space Treaty.