The Nancy Grace Roman Space Telescope will have sensitivity and resolution comparable to the Hubble Space Telescope, but with a field of view 100 times larger, combining excellent image quality with survey power. The Roman Space Telescope observatory will utilize an existing 2.4-meter AFTA (Astrophysics-Focused Telescope Assets) telescope, donated to NASA by another agency, which will be located at the second Sun-Earth Lagrange point (L2).


Artistic rendering of WFIRST and Mirror Assembly


Roman has two instruments to execute the mission science program:

  1. A Wide Field Instrument (WFI) operating in the 0.5–2.0 micron range. The WFI will have 7 imaging filters, a grism (for redshift measurements in support of baryon acoustic oscillation science), and a prism for spectroscopic characterization of supernovae.
  2. A Coronagraph Instrument (CGI) operating in the 0.4–1.0 micron range. This Technology Demonstration instrument will have both an imaging detector (for exoplanet detection) and an Integral Field Unit (for exoplanet spectroscopy). The CGI was added to the mission as a “New Worlds Technology Development Program,” which was the top medium-scale priority in space described in the NWNH Decadal Survey Report.

Roman Imaging Capabilities

Telescope Aperture

2.4 meter

Field of View

45'x23'; 0.28 sq deg

Pixel Scale

0.11 arcsec

Wavelength Range

0.5-2.0 µm
Filters F062 F087 F106 F129 F158  F184 W146
Wavelength (µm)  0.48-0.76 0.76-0.98 0.93-1.19 1.13-1.45 1.38-1.77 1.68-2.00 0.93-2.00
Sensitivity (5σ AB mag in 1 hr)  28.5 28.2 28.1 28.0 28.0 27.5 28.3


Roman Spectroscopic Capabilities

  Field of View
(sq deg) 
Wavelength (µm)  Resolution  Sensitivity  (AB mag)
(1Oσ per pixel in 1hr) 
Grism 0.28 sq deg 1.00-1.93 461 20.5 at 1.5 µm
Prism 0.28 sq deg 0.75-1.80 80-180 23.5 at 1.5 µm



Roman Coronagraphic Capabilities

  Wavelength (µm) Inner Working Angle (arcsec) Outer Working Angle (arcsec) Detection Limit* Spectral Resolution 
Imaging 0.5-0.8 0.15 (exoplanets)
0.48 (disks)
0.66 (exoplanets)
1.46 (disks)
10-9 contrast (after post-processing) 47-75
Spectroscopy 0.675-0.785


* Based on current best estimates of performance.

Download Instrument Capabilities Chart

Citation: Roman Reference Information (Phase B payload design)

Contact the Roman Team