A Request for Information (RFI) invoked by NASA asks the science and engineering community to come up with ideas for a mission to Europa, one of Jupiter’s moons, to search for life and address crucial questions of the ambiguous celestial body. Ideas must cost less than $1 billion—excluding the launch vehicle. The vehicle can meet as many appropriate needs as possible, as recommended by the National Research Council’s 2011 Planetary Science Decadal Survey regarding the study of Europa. The deadline to submit ideas is May 30.
Europa represents one of the most interesting sites in outer space. However, because of the harsh radiation environment, any mission must consider the unique level of protection for spacecraft and instruments. Planetary protection requirements also must be met to protect Europa’s potentially habitable ocean. That means no viable organism can come into contact with Europa’s ocean.
NASA is currently funding the development of instruments specifically intended for a mission to Europa. Congress appropriated $80 million for this project in Fiscal Year 2014, with an additional $15 million proposed for 2015.
Previous missions to Europa point to the existence of a liquid water ocean, which contains more liquid than all of Earth’s oceans combined, under an icy crust that completely covers the moon. In addition, the Hubble Space Telescope observed water vapor above the moon’s frozen south polar region in December 2013—there was evidence of water plumes erupting off the moon’s surface.
Still, those previous visits were limited. The Galileo spacecraft, launched in 1989 by the space shuttle, was the only mission able to make repeated trips to Europa. It passed close to the moon less than 12 times.
That said, the Decadal Survey has deemed a mission to Europa as the highest priority for NASA. It prioritizes five objectives: characterize the extent of the ocean and its connection to the interior; characterize the ice shell and subsurface water, focusing on heterogeneity and the nature of the ice-ocean exchange on the surface; determine the surface’s compositions and chemistry—specifically related to habitability; understand the formation of surface feature—including sites of recent or current activity—and identify candidate sites for future detailed exploration; and, understand Europa’s space environment and its interaction with the magnetosphere.