Wide Field Infrared Survey Telescope (WFIRST) is the highest priority space based telescope project of the New Worlds, New Horizons in Astronomy and Astrophysics (2010) report by the Board on Physics and Astronomy (BPA) and the Space Studies Board
WFIRST is a wide-field-of-view near-infrared imaging and low-resolution spectroscopy observatory that will tackle two of the most fundamental questions in astrophysics: Why is the expansion rate of the universe accelerating? And are there other solar systems like ours, with worlds like Earth? In addition, WFIRST’s surveys will address issues central to understanding how galaxies, stars, and black holes evolve. WFIRST will carry out a powerful extrasolar planet search by monitoring a large sample of stars in the central bulge of the Milky Way for small deviations in brightness due to microlensing by intervening solar systems. This census, combined with that made by the Kepler mission, will determine how common Earth-like planets are over a wide range of orbital parameters
To measure the properties of dark energy, WFIRST will employ three different techniques: it will image about 2 billion galaxies and carry out a detailed study of weak lensing that will provide distance and rate-of-growth information; it will measure spectra of about 200 million galaxies in order to monitor distances and expansion rate using baryon acoustic oscillations; and finally, it will detect about 2,000 distant supernova explosions, which can be used to measure distances. WFIRST provides the space-unique measurements that, combined with those from LSST (the committee’s highest-priority ground-based project), are essential to advance understanding of the cause of cosmic acceleration. In addition, WFIRST will survey large areas of sky to address a broad range of Astro2010 science questions ranging from understanding the assembly of galaxies to the structure of the Milky Way. WFIRST will also offer a guest investigator program supporting both key projects and archival studies to address a broad range of astrophysical research topics.
WFIRST is a 1.5-meter telescope that will orbit the second Lagrange point (L2), 1.5 million km from Earth. It will image the sky at near-infrared wavelengths and perform low-resolution infrared spectroscopy. The spacecraft hardware that was used as a template for studying WFIRST was one of the two JDEM proposals that were submitted to the committee—the JDEM-Omega proposal. This was used as a basis for the cost and technical evaluation assessment. Undoubtedly, design improvements are possible, but its capabilities are essentially identical to those envisaged for WFIRST