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Frequently Asked Questions

What is the Roman Space Telescope?

The Nancy Grace Roman Space Telescope, formerly the Wide Field Infrared Survey Telescope (WFIRST), is a NASA space observatory currently in development. The mission was recommended as the top priority for the next decade of astronomy in the 2010 United States National Research Council Decadal Survey. In February 2016, it was approved for development and launch. It is designed to settle essential questions in the areas of dark energy, exoplanets, and astrophysics.

Wait a sec, what happened to WFIRST?

WFIRST has been renamed to honor a NASA pioneer, Nancy Grace Roman. Read about her career and contributions to the nation's space program.

How big is the Roman Space Telescope?

It has a primary mirror that is 2.4 meters in diameter (7.9 feet), and is the same size as the Hubble Space Telescope's primary mirror. The mirror has the same sensitivity as Hubble’s primary mirror but will only be one fifth the weight, showcasing an advancement in telescope technology. It will have the sensitivity and resolution comparable to Hubble, but with a field of view 100 times larger, combining excellent image quality with survey power.

How many instruments will there be?

The Roman Space Telescope will have two instruments, the Wide Field Instrument (WFI) and the Coronagraph Instrument (CGI) technology demonstration. The WFI provides wide field imaging and spectroscopy, with performance characteristics optimized for cosmology and exoplanet surveys. The CGI provides high contrast imaging and spectroscopy for observations of exoplanets and debris disks. The WFI is a 288-megapixel multi-band near-infrared camera, providing a sharpness of images comparable to that achieved by the Hubble Space Telescope over a 0.28 square degree field of view, 100 times larger than that of Hubble. The Coronagraphic Instrument is a high-contrast, small field of view camera and spectrometer covering visible and near-infrared wavelengths using novel starlight-suppression technology.

What are the science themes?

The mission will focus on dark energy and dark matter, exoplanets, and a wide range of infrared astrophysics and planetary science topics. Its surveys include a large area, high-latitude imaging and spectroscopic survey that enables high-precision cosmological measurements with weak lensing and galaxy clustering, a time-domain survey that enables discovery and light curve monitoring of thousands of Type Ia supernovae, a time-domain survey of the galactic bulge that enables discovery of thousands of exoplanets at AU and larger separations via gravitational microlensing. These surveys will be designed with broad community input to maximize other science investigations that can be pursued with these enormous datasets. An additional General Observer (GO) program will enable a wide range of studies in astrophysics and planetary science.

How will it look for dark matter, dark energy and exoplanets?

The Roman Space Telescope will study dark matter and dark energy with several techniques. It will perform large surveys of galaxies and galaxy clusters to see the effects of dark matter and energy on their shapes and distributions in the universe. All told, more than a billion galaxies will be observed. It will also observe distant Type Ia supernovae to use them as tracers of the accelerating expansion of the universe, providing an independent means of characterizing dark energy. It will provide a huge step forward in our understanding of dark matter and dark energy. The Roman Space Telescope will also study exoplanets with two different techniques: microlensing and through the use of a coronagraph technology demonstration. The mission will stare at the a dense star region toward the direction of the center of our Milky Way galaxy to observe microlensing events. The coronagraph instrument will demonstrate new technologies for performing direct imaging of exoplanets and disks around nearby stars.

Have the science teams already been selected for the mission?

No. Input is being obtained from the community in multiple stages. In the first stage, teams of scientists were selected in a competitive process to support mission development during Formulation (Phases A and B) and part of Phase C (see the Status FAQ below). These teams constituted the Formulation Science Working Group (FSWG), with the task of developing candidate survey designs, detailed performance requirements needed to execute those surveys and maximize return of the General Observer and archival research programs, and support the Project with trade studies. Final survey designs and tie allocations will be decided much closer to launch. The 5-year term of the FSWG concludes roughly a year into Phase C, and NASA anticipates a future competition for science teams for implementation of the Roman Space Telescope observing program.

Will the Roman Space Telescope data have any proprietary time?

There will be no proprietary period for the data, and 100% of observing time will be competed.

What is the status of the Roman Space Telescope?

It is currently in the Final Design and Fabrication phase (“Phase C”). NASA missions undergo various phases, as follows:

  • Phase A: Concept & Technology Development
  • Phase B: Preliminary Design and Technology Completion
  • Phase C: Final Design and Fabrication
  • Phase D: System Assembly, Integration and Test, and Launch
  • Phase E: Operations and Sustainment
  • Phase F: Closeout

When is the Roman Space Telescope slated to launch?

Preparations are on track for a mid-2020s launch.

What institutions are involved?

The mission is managed by NASA’s Goddard Space Flight Center with participation by the Jet Propulsion Laboratory, the Space Telescope Science Institute (STScI), the Infrared Processing and Analysis Center (IPAC), several industrial partners, and science team members from a large number of research institutions. The Science Center functions are the joint responsibility of IPAC, STScI, and GSFC. The primary industrial partners are Ball Aerospace, L3Harris, and Teledyne Imaging Sensors.

What additional science will the Roman Space Telescope enable?

In addition to the survey programs to study dark energy and exoplanets, the Roman Space Telescope will allow an enormous range of scientific investigations in astrophysics and planetary science. It will have a robust General Observer program that will enable the scientific community to study topics that include solar system objects, exoplanet transits, brown dwarfs and stellar remnants, stellar populations of the Milky Way and nearby galaxies, galaxy evolution, quasars, gravitational lenses, and the sources of reionization.

Who will launch the mission into space?

The Roman Space Telescope project is currently studying launch vehicle options. Launch vehicles are not typically selected until several years before launch.

What orbit will the Roman Space Telescope be in?

It will operate from a Quasi-Halo orbit around the second Sun-Earth Lagrange point (L2).

What is the mission lifetime?

Under current plans, the Roman Space Telescope will have a primary mission lifetime of 5 years, and is being designed to support a 5 year extended mission (fuel is the only expendable).

Will it have a General Observer or Archival Researcher Program?

Yes. Under current plans, 25% of the 5-year prime mission is expected to be dedicated to the General Observer (GO) programs and 5% would be devoted to coronagraphic technology demonstration. The rest is devoted to surveys for microlensing, and dark energy measurements. These surveys should also yield data useful for general astrophysics to be done in archival mode. NASA intends to fund an Archival Researcher (AR) program to support full scientific exploitation of the data sets. A larger fraction of time (likely 100%) of an extended mission would be operated in GO mode.




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