Today NASA issued an Announcement of Opportunity (AO). The agency is looking for instruments that can be included on a spacecraft for a planned unmanned mission to Europa. Researchers have long speculated that the distant moon could be home to some form of life.

Between now and April 2015 20 proposals will be selected and $25 million, in total, of funding will be available for the further development of the selected proposals. After the initial development phase, eight instruments will be selected for inclusion in the Europa mission.

“The possibility of life on Europa is a motivating force for scientists and engineers around the world. This solicitation will select instruments which may provide a big leap in our search to answer the question: are we alone in the universe,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate in a statement.

Proposals must be compatible with the proposed mission which involves either orbiting or performing multiple flybys of Europa. Instruments would need to meet one or more of the goals outlined in the National Resource Council’s (NRC) Planetary Decadal Survey.

Those prioritize include a characterization of the extent of the ocean, the ice shell and water and a better understanding of the moon’s deeper interior. Additionally NASA seeks to better understand the planets surface and chemistry, how this relates to potential habitability and its atmosphere. Finally, but perhaps most important NASA is looking for a better understanding of the planets surface and candidate sites for more detailed future studies.

The characterization of landing sites ranked fourth in the Planetary Decadal Survey’s list of priorities, however NASA places a very high priority on it. The agency hopes to find potential landing sites for a future rover mission, similar to those currently underway on Mars. Currently there isn’t sufficient data for the selection of landing sites or the design of a craft that can safely land on the surface.

Currently, Europa is believed to be entirely covered by an ocean of liquid water, buried beneath an ice sheet. That ocean is thought to contain three times more water than all of Earth’s oceans combined.

A full copy of the Announcement of Opportunity can be found here.