NRC Says Yes to NASA Participation in ESA's Euclid Mission

The National Research Council (NRC) issued its report today on whether NASA should make a modest hardware contribution to Europe’s Euclid dark energy mission valued at about $20 million in exchange for one seat on Euclid’s 12-person science committee and early access to Euclid data.  The NRC endorsed NASA’s plan.

The report was requested by NASA and executed by the NRC on an expedited basis because the European Space Agency (ESA) needs an agreement to be signed through the U.S. State Department by the end of April if the United States wants to participate.  Consequently the committee was able to meet only once.   At that meeting, several committee members expressed concern about whether even a small contribution to Euclid would negatively affect plans for a U.S. dark energy mission.   The most recent NRC decadal survey for astronomy and astrophysics identified the Wide-Field Infrared Survey Telescope (WFIRST) as its highest priority large space mission, which has dark energy research as one of its three objectives.

Plans for building WFIRST are being delayed because of cost overruns on the James Webb Space Telescope (JWST).   The earliest WFIRST launch date now is about 2022 while Euclid is planned for launch in 2019.   By providing the hardware for the Euclid mission, U.S. scientists will get early access to Euclid’s data and one of 12 seats on the Euclid science team.  The agreement does not involve any exchange of funds between the United States and Europe.  NASA will pay for the hardware development and provide the hardware to ESA.  Exactly what hardware NASA will provide still must be negotiated, but ESA is particularly interested in U.S. near-infrared detectors.

The committee was careful to state that the contribution to Euclid “should be made in the context of a strong U.S. commitment to … WFIRST….”  and its “intent has been clear that this report does not alter … plans for implementation of the [decadal] survey’s priorities.”

The NRC committee that produced the 2010 decadal survey, New Worlds New Horizons, and recommended development of WFIRST was aware of ESA’s plans for Euclid, but ESA had not yet selected Euclid for development.  That occurred last fall.    By then, the depth of the cost overrun on JWST had crystallized and, coupled with the outlook for sharply constrained budgets for many years, NASA began looking for other ways to pursue dark energy research.   Dark energy is thought to comprise more than 70 percent of the universe.  It is called “dark” because scientists do not know what it is.   They know the universe is expanding at a rate faster than earlier theorized and coined the term dark energy to refer to the force or phenomenon that is fueling that expansion.

NASA earlier proposed a greater U.S. contribution to Euclid, but the U.S. astrophysics community was not supportive for fear it would drain resources from WFIRST or other U.S. space science priorities.   The $20 million proposal that NASA offered this time apparently was the right order of magnitude to win that support.  An internal NASA advisory subcommittee earlier had approved the idea as well.  The $20 million represents about 10 percent of the cost of Euclid’s instruments and is usually referred to as NASA having a “10 percent role in Euclid,” but it is not 10 percent of the cost of the project overall.