Research on terrestrial analogs of the Europa environment will allow the development of and provide proof-of-concept testing for new technologies required for the exploration of Europa. The use of radar to explore thick glacial ice sheets on Earth is an obvious example of the relevance of this approach. The exploration of the ice-water and ice-rock boundaries on terrestrial ice as an abode for life also may offer valuable lessons in exploration strategy.

COMPLEX recommends that NASA continue its collaborative efforts with other government agencies to explore sub-ice freshwater lakes (such as Antarctica's Lake Vostok) and sub-ice-shelf ocean environments as a means of understanding scientific, technological, and operational issues associated with the exploration of isolated environments.

COMPLEX recommends that peer review be used to select Earth-analog programs and investigators to ensure a significant and appropriate level of participation by all of the relevant scientific communities.

The exploration of Europa is an interdisciplinary venture, and various aspects of the necessary science and technology background are being investigated at present by federal agencies other than NASA, including the National Science Foundation, the Department of Defense, the Department of Energy, and the National Oceanic and Atmospheric Administration and the Office of Air and Space Commercialization within the Department of Commerce. Some of the Earth-analog studies, for example those in Greenland and Antarctica, will require sensitivity to international agreements and treaties. Additional international issues could arise in connection with the possible biological contamination of Europa by spacecraft from Earth, the potential for back-contamination of Earth if samples from Europa that may contain biologically active materials should ever be returned to Earth, or in launching spacecraft that carry radioisotope thermoelectric generators.

COMPLEX recommends that NASA, to avoid ''reinventing the wheel," look to other government agencies to deal with some of the scientific and technological issues and to cooperate with governments of other countries in exploring Earth analogs.

COMPLEX endorses the planetary protection procedures and policies articulated in previous NASA and NRC documents and recommends that appropriate planetary protection measures be determined and implemented on all relevant spacecraft missions.²

1. Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press, Washington, D.C., 1994, pages 8 and 191.

2. See, for example, Space Studies Board, National Research Council, Evaluating the Biological Potential in Samples Returned from Planetary Satellites and Small Solar System Bodies: Framework for Decision Making, National Academy Press, Washington, D.C., 1998.