NASA is moving forward with plans for its next big eye in the sky: the Wide Field InfraRed Survey Telescope (WFIRST). Scheduled to fly in the mid-2020s – after the 2018 launch of the James Webb Space Telescope – the new orbital instrument will have a field of view 100 times bigger than that of the Hubble Space Telescope, but with the same power.
Like many other things in life, telescope design is a matter of trade offs. On the one hand, they can be powerful instruments that can only see a bit of the sky, or they can be weaker devices that can see much more. According to NASA, the WFIRST squares the circle with a telescope that has both wide vision and powerful magnification.
WFIRST began in 2011 as a project to study dark energy, but has since expanded to include a more general survey into the evolution of the Universe and to hunt for potentially habitable exoplanets.
The mission gained approval from NASA's Agency Program Management Council on Wednesday.
WFIRST will carry the first conformable mirrors to fly in space that can correct for errors in telescope imaging. It will have two key instruments. The first is the Wide Field Instrument for sky surveys. This will collect images of large regions of space in the near infrared to seek out exoplanets as well as learning more about dark matter and measuring the distance of supernovae to track the distribution and growth of cosmic structures.
The second instrument is the Coronagraph, which is designed to block the glare of individual stars and reveal the faint light of planets orbiting around them. This not only allows the WFIRST to see exoplanets directly, but to bring to bear instruments, such as spectrographs, to study the physics and chemistry of their atmospheres for possible signs of life.
NASA says that after WFIRST launches, it will position itself at the Earth-Sun L2 about one million miles from Earth directly opposite the Sun, where it will hold a stable position.
"WFIRST has the potential to open our eyes to the wonders of the universe, much the same way Hubble has," says John Grunsfeld, astronaut and associate administrator of NASA's Science Mission Directorate. "This mission uniquely combines the ability to discover and characterize planets beyond our own solar system with the sensitivity and optics to look wide and deep into the universe in a quest to unravel the mysteries of dark energy and dark matter."
The video below outlines the WFIRST mission.