The JDEM mission will be jointly funded and developed by NASA and the Office of High Energy Physics at the U.S. Department of Energy (DOE). The mission will make precise measurements of the expansion rate of the universe to understand how this rate has changed with time. These measurements will yield vital clues about the nature of dark energy.

JDEM will also represent a partnership between astronomers and physicists. The project will be managed at NASA's Goddard Space Flight Center, in Greenbelt, Maryland. Goddard played a major role in building and managing Hubble and WMAP. The Center is eager to work with DOE and other partner institutions around the world to build the payload and spacecraft. Launch is planned for the middle of the next decade.