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FIGURE 7.3 WFIRST is an infrared telescope with a three‐mirror design. It will have HgCdTe detectors with
144 megapixels in total and angular resolution of 200 milliarcseconds. The sensitivity should be about 200
nJy or 26 th magnitude, enabling shape measurements and photometric redshifts to a depth of 100,000
galaxies per square degree over half the sky. Spectroscopy will be achieved with a grism or prism and will
rely mainly on measurement of H alpha out to a redshift of about 1.8 Credit: JDEM Project, NASA‐GSFC.
the mission, but firmly believes it should not drive the mission hardware design or implementation cost.
NASA should consider creative ways to enable the most flexible possible general investigator program
consistent with the current spacecraft and instrument suite.
WFIRST employs the JDEM-Omega design, conceived and developed in a collaboration between
DOE and NASA. Other versions of a JDEM mission have been endorsed in two previous NRC reports. 14
Much progress has been made in defining the scientific objectives, and a variety of mission concepts have
been discussed and compared. This continuing interagency collaboration on the proposed WFIRST is
important both scientifically and technically. In addition, the committee is aware that plans are now
underway in Europe for a similar mission, Euclid, which has many of the same scientific goals as
WFIRST. Euclid is also in its definition phase and is competing with PLATO and Solar Probe for one of
the two M-class launch slots of the European Space Agency’s (ESA’s) Cosmic Vision program, now
scheduled for 2017 and 2018. There have been discussions between the U.S. agencies and ESA about
mounting a joint mission, which could be a positive development if it leads to timely execution of a
program that fully supports all of the key science goals of WFIRST (planet microlensing, dark energy
science, general investigations) and leads to savings overall. It is expected that the United States will play
a leading role in this top-priority mission.
WFIRST addresses fundamental and pressing scientific questions and contributes to a broad
range of astrophysics. It complements the proposed ground-based program in two key science areas: dark
energy science and the study of exoplanets. It is an integral part of coordinated and synergistic programs
in fields in which the United States has the leading role. It also presents opportunities for interagency and
perhaps international collaboration that will tap complementary experience and skills. It also presents
relatively low technical and cost risk, making it feasible to complete within the decade, even in a
constrained budgetary environment. For these reasons it is the top-priority recommendation for a spacebased
initiative. A 2013 new start should enable launch in 2020.
14 National Research Council, Connecting Quarks with the Cosmos (2003) and NASA's Beyond Einstein
Program: An Architecture for Implementation (2007), The National Academies Press, Washington, D.C.
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