DARPA (the U.S. Defense Advanced Research Projects Agency) is looking for a private company to build spacecraft to orbit the moon and search for water.

A program solicitation that DARPA released on April 14 outlines the plan for the LASSO (Lunar Assay via Small Satellite Orbiter) program, with the goal of developing a system of one or several affordable satellites.

The hope is that, in four years or less, the LASSO spacecraft will map the entire surface of the moon — while circling in a very low orbit.