Methods and measurements to assess physical and geochemical conditions at the surface of Europa

An international effort dedicated to the science exploration of Jupiter system planned by ESA and NASA in the beginning of the next decade includes in-depth science investigation of Europa. In parallel to EJSM (Europa-Jupiter System Mission) Russia plans a Laplace-Europa Lander mission, which will include another orbiter and the surface element: Europa Lander. In-situ methods on the lander provide the only direct way to assess environmental conditions, and to perform the search for signatures of life. A critical advantage of such in situ analysis is the possibility to enhance concentration and detection limits and to provide ground truth for orbital measurements. The science mission of the lander is biological, geophysical, chemical, and environmental characterizations of the Europa surface. This review is dedicated to methods and strategies of geophysical and environmental measurements to be performed at the surface of Europa, and their significance for the biological assessment, basing on the concept of a relatively large softly landed module, allowing to probe a shallow subsurface. Many of the discussed methods were presented on the workshop “Europa Lander: Science Goals and Experiments” held in Moscow in February 2009. Methods and instruments are grouped into geophysical package, means of access to the subsurface, methods of chemical and structural characterization, and methods to assess physical conditions on the surface.