~2025?

WFIRST

A recent National Academy of Sciences decadal survey of astronomy recommended as its top priority a new visible to infrared wavelength space telescope for the 2020s that could build on the legacy and results of the Hubble, Spitzer, and James Webb Space Telescopes to answer fundamental and unresolved questions in cosmology, galactic and extragalactic astronomy, and even solar system studies. Specifically, the goal would be to conduct an all-sky survey with a space telescope that could obtain images as sharp as those from the Hubble Space Telescope, but covering one hundred times the area of sky per observation. It was a tall order, but the astronomy science and engineering communities have designed a new mission, called the Wide-Field Infrared Survey Telescope, or WFIRST, that would meet those objectives.

WFIRST would launch around 2025 and consist of a telescope almost 8 feet (2.4 meters) in diameter, with advanced imaging spectrometer and coronagraph instruments—the latter designed specifically to block light from the brightest part of a star in order to resolve nearby objects, such as planets. The solar-powered observatory would be navigated to one of the Lagrange gravitational balance points between the Earth and the Sun (the L2 point, on the opposite side of the Moon’s orbit), where it would co-orbit with the Earth, close enough for high-bandwidth communication and data transfer, but far enough away to avoid light pollution from the Earth or Moon. The observatory’s nominal lifetime would be about six years.

Like the Hubble Space Telescope, WFIRST is being designed to achieve many diverse scientific objectives. These include completing a census of nearby exoplanets, with direct imaging and spectroscopy of a significant sampling of them, as well as studying the nature of dark energy by observing its effects on supernovae, galaxies, and other large-scale structures. The survey nature of the observatory would also, in general, provide a rich and unprecedented data set that astronomers would be able to mine for decades. Just like pioneering space telescopes before it, WFIRST would open a new window on the universe, and it’s exciting to ponder what new and surprising discoveries could await.

Artist’s rendering of WFIRST with an image of the spiral galaxy NGC 2441. Observations of supernovae in galaxies like this (example circled in red) can provide new insights into dark energy.