WFIRST: new large space telescope

In autumn next year, telescope James Webb, being in development since middle of 1990th, will be launched at last. Astronomers have high hopes for this instrument, which might considerably enhance our knowledge about Universe. Meanwhile, NASA have already started works on the next large space telescope, scheduled for launch in the next decade. This is WFIRST - Wide-Field Infrared Survey Telescope.

Image: NASA

WFIRST will observe sky in the near infrared range. The original plans were to use primary mirror 1,2 meter across, and launch telescope to the geostationary orbit with Atlas-5 rocket. Plans were changed two years ago, when US National Reconnaissance Office gave to NASA two 2,4 meter mirrors, left from cancelled spy satellites missions. These mirrors are much more sensitive, so design was radically reworked. According to new design, telescope will be positioned in Lagrange L2 point and for the launch will be used Delta 4-heavy or Falcon heavy from SpaceX.

Image: NASA

It is possible that to the launch of WFIRST, James Webb will be still in service, in the same L2 point. There is no problem, because objects, located in L2 point are moving on the complicated trajectory, so there may be several objects in L2 simultaneously.

With 2,4 meters primary mirror, WFIRST will have the same resolution as Hubble, but there is one difference - WFIRST is wide angle telescope. Is field of view is 100 times wider than of Hubble, so it is able to image larger parts of the sky. Its primary target - measures of the dark matter and its influence on the galaxies.

Image: NASA - Hubble and WFIRST fields of views comparison

Another goal - direct observations of exoplanets. WFIRST will be equipped with coronograph - shield, shadowing the star and allowing to look at its planets. Scientists suggest that it will be able to directly observe exoplanets of Uranus size. 

Image: NASA

Launch of WFIRST is scheduled on September 2025, with sevice up to 6 years. For now, cost of mission is 3,2 billion dollars ($800M increase to the last year estimates).