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Publication date: 
25 November 2008

Despite NASA and the Department of Energy’s (DOE) struggle with budget constraints and mission prioritization, the Joint Dark Energy Mission (JDEM) appears to be on track. FYI previously reported on NASA and DOE’s commitment to JDEM in FYI number 74 and 78 respectively.

Both agencies recently signed a Memorandum of Understanding that will secure JDEM’s status as the first Beyond Einstein mission. NASA and DOE collaborated on a 2006 National Research Council study carried out by the Beyond Einstein Assessment Committee. That committee recommended JDEM as the first Beyond Einstein mission. JDEM will measure the expansion of the universe and the way in which it is growing to better understand the nature of dark energy. Dark energy is estimated to account for 73 percent of the total mass-energy content of the universe.

In their report, the committee reviewed three proposed JDEM mission plans. Those three missions are the Supernova Acceleration Probe (SNAP), the Dark Energy Space Telescope (DESTINY), and the Advanced Dark Energy Physics Telescope (ADEPT). According to NASA and DOE briefings, a JDEM mission is expected to launch sometime around 2015.

The committee reviewed five other Beyond Einstein missions, most notably the Laser Interferometer Space Antenna (LISA) that would be designed to detect gravitational waves. Although LISA is a highly regarded mission, it is still in a preliminary stage. The European Space Agency (ESA) is scheduled to launch the LISA Pathfinder, which will test a number of proposed LISA systems, in 2009.

The memorandum outlines NASA and DOE’s agreement on JDEM, including responsibilities, financial liability, and data sharing procedures. NASA will manage the overall mission, and provide mission systems engineering, integration and testing, launch operations, and mission operations. DOE will be responsible for the fabrication of a major science instrument and a science operations center. Both agencies will offer support throughout the mission and participate in the dark energy science operations. Both agencies will be liable for the costs of their assigned responsibilities, and any cost overruns they manage. NASA and DOE will have access to all data produced by the mission, and must agree if any data is to be held back from the public one year after it is acquired.

Congress will undoubtedly be pleased with the memorandum, after months of pressure to finalize the agreement as noted in FYI number 76. In a July draft report on the FY 2009 Energy and Water Development Appropriations Bill, the House Appropriations noted that the committee had “consistently supported the DOE/NASA Joint Dark Energy Mission (JDEM)…” The report went on to say that “The Committee is pleased with the efforts made by the Office of Science to work with NASA… and encourages the organizations to formalize the agreement with a Memorandum of Understanding as soon as possible.” Ultimately the committee recommended the full budget request of $10,030,000 for conceptual designs for JDEM.

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