Nancy Grace Roman Space Telescope

File:WFIRST model.stl

The design of the Roman Space Telescope shares a heritage with various proposed designs for the Joint Dark Energy Mission (JDEM) between NASA and the Department of Energy (DOE).

The original design, called WFIRST Design Reference Mission 1, was studied in 2011–2012, featuring a {{cvt|1.3|m|ft|adj=on}} diameter unobstructed three-mirror anastigmat telescope.{{cite arXiv |eprint=1208.4012|last1=Green |first1=J. |last2=Schechter |first2=P. |last3=Baltay |first3=C. |last4=Bean |first4=R. |last5=Bennett |first5=D. |last6=Brown |first6=R. |last7=Conselice |first7=C. |last8=Donahue |first8=M. |last9=Fan |first9=X. |last10=Gaudi |first10=B. S. |last11=Hirata |first11=C. |last12=Kalirai |first12=J. |last13=Lauer |first13=T. |last14=Nichol |first14=B. |last15=Padmanabhan |first15=N. |last16=Perlmutter |first16=S. |last17=Rauscher |first17=B. |last18=Rhodes |first18=J. |last19=Roellig |first19=T. |last20=Stern |first20=D. |last21=Sumi |first21=T. |last22=Tanner |first22=A. |last23=Wang |first23=Y. |last24=Weinberg |first24=D. |last25=Wright |first25=E. |last26=Gehrels |first26=N. |last27=Sambruna |first27=R. |last28=Traub |first28=W. |last29=Anderson |first29=J. |last30=Cook |first30=K. |display-authors=1 |title=Wide-Field InfraRed Survey Telescope (WFIRST) Final Report |year=2012 |class=astro-ph.IM }} It contained a single instrument, a visible to near-infrared imager/slitless prism spectrometer.

In 2012, another possibility emerged: NASA could use a second-hand National Reconnaissance Office (NRO) telescope made by Harris Corporation to accomplish a mission like the one planned for WFIRST. NRO offered to donate two telescopes, the same size as the Hubble Space Telescope but with a shorter focal length and hence a wider field of view.{{cite web|url=https://www.nytimes.com/2012/06/05/science/space/repurposed-telescope-may-explore-secrets-of-dark-energy.html|title=Ex-Spy Telescope May Become a Space Investigator|newspaper=The New York Times|date=June 4, 2012|access-date=March 17, 2021|archive-date=4 September 2019|archive-url=https://web.archive.org/web/20190904165335/https://www.nytimes.com/2012/06/05/science/space/repurposed-telescope-may-explore-secrets-of-dark-energy.html|url-status=live}} This provided important political momentum to the project, even though the telescope represents only a modest fraction of the cost of the mission and the boundary conditions from the NRO design may push the total cost over that of a fresh design. This mission concept, called WFIRST-AFTA (Astrophysics Focused Telescope Assets), was matured by a scientific and technical team;{{cite web|url=http://wfirst.gsfc.nasa.gov/science/sdt_public/WFIRST-AFTA_SDT_Final_Report_Rev1_130523.pdf|title=WFIRST-AFTA SDT Final Report, revision 1|date=May 23, 2013|access-date=March 17, 2021|archive-date=4 April 2014|archive-url=https://web.archive.org/web/20140404000259/http://wfirst.gsfc.nasa.gov/science/sdt_public/WFIRST-AFTA_SDT_Final_Report_Rev1_130523.pdf|url-status=live}} {{PD-notice}} this mission is now the only present NASA plan for the use of the NRO telescopes.{{cite news |author=Leone |first=Dan |date=June 4, 2013 |title=Only NASA Astrophysics Remains in Running for Donated NRO Telescope – For Now |publisher=SpaceNews |url=http://spacenews.com/35628only-nasa-astrophysics-remains-in-running-for-donated-nro-telescope-for/ |url-status=live |access-date=March 17, 2021 |archive-url=https://web.archive.org/web/20230202194504/http://spacenews.com/35628only-nasa-astrophysics-remains-in-running-for-donated-nro-telescope-for/ |archive-date=2 February 2023}} The Roman baseline design includes a coronagraph to enable the direct imaging of exoplanets.{{cite web|url=http://wfirst.gsfc.nasa.gov/science/sdt_public/WFIRST-AFTA_SDT_Interim_Report_April_2014.pdf|title=WFIRST Science Definition Team Interim Report|publisher=NASA|date=April 30, 2014|access-date=August 28, 2014|archive-date=5 April 2015|archive-url=https://web.archive.org/web/20150405184127/http://wfirst.gsfc.nasa.gov/science/sdt_public/WFIRST-AFTA_SDT_Interim_Report_April_2014.pdf|url-status=live}} {{PD-notice}}

Several implementations of WFIRST/Roman were studied. These included the Joint Dark Energy Mission-Omega configuration, an Interim Design Reference Mission featuring a {{cvt|1.3|m|ft}} telescope,{{cite web|url=http://wfirst.gsfc.nasa.gov/science/sdt_public/WFIRST_Interim_Report.pdf|title=WFIRST IDRM|author=Green & Schechter|date=July 11, 2011|access-date=February 23, 2016|archive-date=9 October 2016|archive-url=https://web.archive.org/web/20161009151130/http://wfirst.gsfc.nasa.gov/science/sdt_public/WFIRST_Interim_Report.pdf|url-status=live}} {{PD-notice}} Design Reference Mission 1{{cite web|url=http://wfirst.gsfc.nasa.gov/science/sdt/sdt_2010_2011/meetings/2012_May/DRM1_120517.pdf|title=WFIRST DRM1|date=May 17, 2012|access-date=February 23, 2016|archive-date=3 March 2016|archive-url=https://web.archive.org/web/20160303055501/http://wfirst.gsfc.nasa.gov/science/sdt/sdt_2010_2011/meetings/2012_May/DRM1_120517.pdf|url-status=live}} {{PD-notice}} with a 1.3 m telescope, Design Reference Mission 2{{cite arXiv|eprint=1208.4012|title=WFIRST DRM2|date=August 15, 2012|last1=Green |first1=J. |last2=Schechter |first2=P. |last3=Baltay |first3=C. |last4=Bean |first4=R. |last5=Bennett |first5=D. |last6=Brown |first6=R. |last7=Conselice |first7=C. |last8=Donahue |first8=M. |last9=Fan |first9=X. |last10=Gaudi |first10=B. S. |last11=Hirata |first11=C. |last12=Kalirai |first12=J. |last13=Lauer |first13=T. |last14=Nichol |first14=B. |last15=Padmanabhan |first15=N. |last16=Perlmutter |first16=S. |last17=Rauscher |first17=B. |last18=Rhodes |first18=J. |last19=Roellig |first19=T. |last20=Stern |first20=D. |last21=Sumi |first21=T. |last22=Tanner |first22=A. |last23=Wang |first23=Y. |last24=Weinberg |first24=D. |last25=Wright |first25=E. |last26=Gehrels |first26=N. |last27=Sambruna |first27=R. |last28=Traub |first28=W. |last29=Anderson |first29=J. |last30=Cook |first30=K. |display-authors=1 |class=astro-ph.IM}} {{PD-notice}} with a {{cvt|1.1|m|ft}} telescope, and several iterations of the AFTA {{cvt|2.4|m|ft}} configuration.

In the 2015 final report, Roman was considered for both geosynchronous orbit and for an orbit around the Sun-Earth Lagrange point L₂. L₂ has disadvantages versus geosynchronous orbit in available data rate and propellant required, but advantages for improved observing constraints, better thermal stability, and more benign radiation environment. Some science cases (such as exoplanet microlensing parallax) are improved at L₂, but the possibility of robotic servicing at either of the locations is currently unknown. By February 2016 it had been decided to use a halo orbit around L₂.

The project is led by a team at NASA's Goddard Space Flight Center in Greenbelt, Maryland. On 30 November 2018, NASA announced it had awarded a contract for the telescope.{{cite news|url=https://www.idahostatejournal.com/news/national/nasa-awards-optical-telescope-assembly-for-wide-field-infrared-survey/article_c775c1ae-014d-5e8d-873f-1f5bd8c8c61b.html|title=NASA Awards Optical Telescope Assembly for Wide-Field Infrared Survey Telescope Mission|publisher=Idaho State Journal|access-date=December 2, 2018|archive-date=3 December 2018|archive-url=https://web.archive.org/web/20181203174338/https://www.idahostatejournal.com/news/national/nasa-awards-optical-telescope-assembly-for-wide-field-infrared-survey/article_c775c1ae-014d-5e8d-873f-1f5bd8c8c61b.html|url-status=dead}} This was for a part called OTA, the Optical Telescope Assembly, and runs to 2025. This is in conjunction with the Goddard Space Flight Center, for which the OTA is planned for delivery as part of this contract.

A February 2019 description of the mission's capabilities is available in a white paper issued by members of the Roman team.{{cite arXiv|last1=Weinberg|first1=David|last2=Wang|first2=Yun|last3=von der Linden|first3=Anja|last4=van der Marel|first4=Roeland|last5=Turnbull|first5=Margaret|last6=Troxel|first6=M. A.|last7=Trauger|first7=John|last8=Szalay|first8=Alexander|last9=Strolger|first9=Louis-Gregory |display-authors=1 |title=The Wide-Field Infrared Survey Telescope: 100 Hubbles for the 2020s|eprint=1902.05569v1|date=February 14, 2019|class=astro-ph.IM}}

The science objectives of Roman aim to address cutting-edge questions in cosmology and exoplanet research, including:

• Answering basic questions about dark energy, complementary to the European Space Agency (ESA) Euclid mission, and including: Is cosmic acceleration caused by a new energy component or by the breakdown of general relativity on cosmological scales? If the cause is a new energy component, is its energy density constant in space and time, or has it evolved over the history of the universe? Roman will use three independent techniques to probe dark energy: baryon acoustic oscillations, observations of distant supernovae, and weak gravitational lensing.
• Completing a census of exoplanets to help answer new questions about the potential for life in the universe: How common are solar systems like our own? What kinds of planets exist in the cold, outer regions of planetary systems? – What determines the habitability of Earth-like worlds? This census makes use of a technique that can find exoplanets down to a mass only a few times that of the Moon: gravitational microlensing. The census would also include a sample of free-floating planets with masses likely down to the mass of Mars.{{cite web|url=https://www.nasa.gov/feature/goddard/2020/unveiling-rogue-planets-with-nasas-roman-space-telescope|title=Unveiling Rogue Planets with NASA's Roman Space Telescope|website=nasa.gov|date=August 17, 2020|publisher=NASA|access-date=August 24, 2020|archive-date=27 August 2020|archive-url=https://web.archive.org/web/20200827060106/https://www.nasa.gov/feature/goddard/2020/unveiling-rogue-planets-with-nasas-roman-space-telescope/|url-status=live}} {{PD-notice}}
• Establishing a guest investigator mode, enabling survey investigations to answer diverse questions about our galaxy and the universe.
• Providing a coronagraph for exoplanet direct imaging that will provide the first direct images and spectra of planets around our nearest neighbors, similar to our own giant planets.
• Detection of primordial black holes.{{cite web |last1=Balzer |first1=Ashley |title=How NASA's Roman Mission Will Hunt for Primordial Black Holes - NASA |url=https://www.nasa.gov/missions/roman-space-telescope/how-nasas-roman-mission-will-hunt-for-primordial-black-holes/ |publisher=NASA |access-date=12 May 2024 |date=7 May 2024}}

File:Scheme of Roman Space Telescope.png|Scheme of the Roman Space Telescope

File:WFIRST Wide Field Instrument.gif|Wide Field Instrument

The telescope is to carry two instruments.

;WFI: The Wide-Field Instrument (WFI) is a 300.8-megapixel camera providing multiband visible to near-infrared (0.48 to 2.30 μm){{Cite web|last=Kruk|first=Jeffrey |date=12 April 2018 |title=WFIRST Update |url=https://science.nasa.gov/science-pink/s3fs-public/atoms/files/Kruk_WFIRST_APAC_April2018.pdf|url-status=live|archive-url=https://web.archive.org/web/20211010211555/https://science.nasa.gov/science-pink/s3fs-public/atoms/files/Kruk_WFIRST_APAC_April2018.pdf|archive-date=10 October 2021|access-date=10 October 2021}} imaging using one wideband and six narrowband filters. A HgCdTe-based focal-plane array captures a 0.28 square degree field of view with a resolution of 0.11 arcseconds. The detector array is composed of 18 H4RG-10 detectors provided by Teledyne.{{cite web|url=https://wfirst.gsfc.nasa.gov/science/presentations/vugraphs/160202WFIRSTSDTH4RG10C.pdf|title=Introduction to WFIRST H4RG-10 Detector Arrays|last=Rauscher|first=Bernard|publisher=NASA|access-date=September 7, 2018|archive-date=27 December 2016|archive-url=https://web.archive.org/web/20161227212745/https://wfirst.gsfc.nasa.gov/science/presentations/vugraphs/160202WFIRSTSDTH4RG10C.pdf|url-status=live}} {{PD-notice}} It also carries both high-dispersion grism and low-dispersion prism assemblies for wide-field slitless spectroscopy.

;CGI: The Coronagraphic Instrument (CGI) is a high contrast coronagraph covering shorter wavelengths (575 nm to 825 nm) using dual deformable mirror starlight-suppression technology. It is intended to achieve a part-per-billion suppression of starlight to enable the detection and spectroscopy of planets with a visual separation of as little as 0.15 arcseconds from their host stars.{{cite web |title=The Nancy Grace Roman Space Telescope |url=https://www.jpl.nasa.gov/missions/the-nancy-grace-roman-space-telescope |website=NASA Jet Propulsion Laboratory (JPL) |access-date=22 February 2023}} CGI is intended as a technology demonstrator for an exoplanet imaging instrument on a future large space-based observatory, such as the Habitable Worlds Observatory (HWO).

File:Romandet-1681946.jpg|Roman's Wide Field Instrument focal plane Engineering Test Unit, containing 18 non-flight H4RG-10 detectors from Teledyne

File:Optical Telescope Assembly for the Roman Space Telescope.jpg|Optical Telescope Assembly

File:Filters on RST Coronagraph Instrument Color Filter Assembly.jpg|The filters on the Coronagraph Instrument's Color Filter Assembly

File:The focal plane mask for the Roman Coronagraph Instrument.jpg|The focal plane mask for the Roman Coronagraph Instrument

File:Roman Space Telescope’s spacecraft bus 03.jpg

On 2 March 2020, NASA announced that it had approved WFIRST to proceed to implementation, with an expected development cost of US$3.2 billion and a maximum total cost of US$3.934 billion, including the coronagraph and five years of mission science operations.{{cite web|url=https://www.nasa.gov/feature/nasa-approves-development-of-universe-studying-planet-finding-mission|title=NASA Approves Development of Universe-Studying, Planet-Finding Mission|publisher=NASA|date=March 2, 2020|access-date=March 14, 2021|archive-date=3 March 2020|archive-url=https://web.archive.org/web/20200303195754/https://www.nasa.gov/feature/nasa-approves-development-of-universe-studying-planet-finding-mission|url-status=live}} {{PD-notice}}

On 20 May 2020, NASA Administrator Jim Bridenstine announced that the mission would be named the Nancy Grace Roman Space Telescope in recognition of the former NASA Chief of Astronomy's role in the field of astronomy.{{cite web|url=https://www.nasa.gov/press-release/nasa-telescope-named-for-mother-of-hubble-nancy-grace-roman/|title=NASA Telescope Named For "Mother of Hubble" Nancy Grace Roman|publisher=NASA|date=May 20, 2020|access-date=March 14, 2021|archive-date=20 May 2020|archive-url=https://web.archive.org/web/20200520180313/https://www.nasa.gov/press-release/nasa-telescope-named-for-mother-of-hubble-nancy-grace-roman/|url-status=live}} {{PD-notice}}

On 31 March 2021, the NASA Office of Inspector General (OIG) released a report that stated that the development of the Nancy Grace Roman Space Telescope had been affected by the COVID-19 pandemic, which hit the US during a particularly important time in the telescope's development. NASA is expecting a total impact of US$400 million due to the pandemic and its effect on subcontractors for the project.{{cite web|url=https://spacenews.com/pandemic-to-cost-nasa-up-to-3-billion/|title=Pandemic to cost NASA up to US$3 billion|publisher=SpaceNews|date=March 31, 2021|access-date=5 April 2021|archive-date=2 February 2023|archive-url=https://web.archive.org/web/20230202194504/https://spacenews.com/pandemic-to-cost-nasa-up-to-3-billion/|url-status=live}}

On 29 September 2021, NASA announced that Roman had passed its Critical Design Review (CDR), and that with predicted impacts from COVID-19 disruptions, and with flight hardware fabrication completed by 2024 followed by mission integration, the launch date would be no later than May 2027.{{cite web |date=September 29, 2021 |title=NASA Confirms Roman Mission's Flight Design in Milestone Review |url=https://www.nasa.gov/feature/goddard/2021/nasa-confirms-roman-missions-flight-design-in-milestone-review/ |url-status=live |archive-url=https://web.archive.org/web/20210930160105/http://www.nasa.gov/feature/goddard/2021/nasa-confirms-roman-missions-flight-design-in-milestone-review/ |archive-date=30 September 2021 |access-date=2021-09-30 |publisher=NASA}} {{PD-notice}}

On 19 July 2022, NASA announced that Roman would be launched on a Falcon Heavy launch vehicle, with a contract specifying readiness by October 2026 and a launch cost of approximately $255 million.

In October 2024, the telescope passed a major ‘spin test’.{{Cite web |author1=Victoria Corless |date=2024-10-19 |title=NASA's next-generation Nancy Roman Space Telescope aces crucial 'spin test' |url=https://www.space.com/roman-space-telescope-testing-spin-test |access-date=2024-10-19 |website=Space.com |language=en}}

In September 2024, the satellite bus which will carry the telescope, was substantially completed.{{Cite web |date=2024-09-17 |title=NASA Completes Spacecraft to Transport, Support Roman Space Telescope - NASA |url=https://www.nasa.gov/missions/roman-space-telescope/nasa-completes-spacecraft-to-transport-support-roman-space-telescope/ |access-date=2024-09-17 |language=en-US}} The following December, the instruments and mirror assembly were successfully integrated onto a section called the "instrument carrier".{{cite web | last=Jamison | first=Miles | title=NASA Completes Roman Space Telescope Payload Integration | website=Executive Gov | date=December 13, 2024 | url=https://executivegov.com/2024/12/nasa-roman-space-telescope-payload-integration/ | access-date=December 16, 2024}}

File:Nancy Roman Hubblecast.jpg, NASA's first Chief of Astronomy, is shown at NASA's Goddard Space Flight Center in Greenbelt, Maryland, in approximately 1972.]]

In the fiscal year 2014, Congress provided US$56 million for Roman, and in 2015 Congress provided US$50 million.{{cite news|last=Foust|first=Jeff|url=http://www.space.com/31533-nasa-wfirst-major-space-telescope-project.html?adbid=10153245128716466&adbpl=fb&adbpr=17610706465|title=NASA's Next Major Space Telescope Project Officially Starts in February|publisher=Space.com|date=January 7, 2016|access-date=January 9, 2016|archive-date=20 October 2017|archive-url=https://web.archive.org/web/20171020135055/https://www.space.com/31533-nasa-wfirst-major-space-telescope-project.html?adbid=10153245128716466&adbpl=fb&adbpr=17610706465|url-status=live}} The fiscal year 2016 spending bill provided US$90 million for Roman, far above NASA's request of US$14 million, allowing the mission to enter the "formulation phase" in February 2016. On 18 February 2016, NASA announced that Roman had formally become a project (as opposed to a study), meaning that the agency intends to carry out the mission as baselined; at that time, the "AFTA" portion of the name was dropped, as only that approach is being pursued. Roman is on a plan for a mid-2020s launch. The total cost of Roman at that point was expected at more than US$2 billion;{{cite web |author=Clery |first=Daniel |date=February 19, 2016 |title=NASA moves ahead with its next space telescope |url=https://www.science.org/content/article/nasa-moves-ahead-its-next-space-telescope |url-status=live |archive-url=https://web.archive.org/web/20221205162519/https://www.science.org/content/article/nasa-moves-ahead-its-next-space-telescope |archive-date=5 December 2022 |access-date=February 20, 2016 |publisher=Science Magazine}} NASA's 2015 budget estimate was around US$2.0 billion in 2010 dollars, which corresponds to around US$2.7 billion in real year (inflation-adjusted) dollars.{{cite web |date=October 8, 2015 |title=NASA Astrophysics: Progress toward New Worlds, New Horizons |url=http://sites.nationalacademies.org/cs/groups/ssbsite/documents/webpage/ssb_168722.pdf |url-status=live |archive-url=https://web.archive.org/web/20160307053144/http://sites.nationalacademies.org/cs/groups/ssbsite/documents/webpage/ssb_168722.pdf |archive-date=7 March 2016 |access-date=February 23, 2016 |publisher=NRC |page=44}}

In April 2017, NASA commissioned an independent review of the project to ensure that the mission scope and cost were understood and aligned.{{cite web|url=https://www.nasa.gov/feature/nasa-taking-a-fresh-look-at-next-generation-space-telescope-plans|title=NASA Taking a Fresh Look at Next Generation Space Telescope Plans|publisher=NASA|date=April 17, 2017|access-date=October 19, 2017|archive-date=21 May 2017|archive-url=https://web.archive.org/web/20170521123220/https://www.nasa.gov/feature/nasa-taking-a-fresh-look-at-next-generation-space-telescope-plans/|url-status=live}} {{PD-notice}} The review acknowledged that Roman offers "groundbreaking and unprecedented survey capabilities for dark energy, exoplanet, and general astrophysics", but directed the mission to "reduce cost and complexity sufficient to have a cost estimate consistent with the US$3.2 billion cost target set at the beginning of Phase B".{{cite web|url=https://www.nasa.gov/feature/nasa-receives-findings-from-wfirst-independent-review-team|title=NASA Receives Findings from WFIRST Independent Review Team|date=October 19, 2017|access-date=October 19, 2017|archive-date=21 October 2017|archive-url=https://web.archive.org/web/20171021094034/https://www.nasa.gov/feature/nasa-receives-findings-from-wfirst-independent-review-team/|url-status=live}} {{PD-notice}} NASA announced (Jan 2018) the reductions{{clarify|date=February 2022}} taken in response to this recommendation, and that Roman would proceed to its mission design review in February 2018 and begin Phase B by April 2018.{{cite web |author=Foust |first=Jeff |date=January 9, 2018 |title=NASA plans to have WFIRST reviews complete by April |url=http://spacenews.com/nasa-plans-to-have-wfirst-reviews-complete-by-april/ |url-status=live |archive-url=https://web.archive.org/web/20230202194505/http://spacenews.com/nasa-plans-to-have-wfirst-reviews-complete-by-april/ |archive-date=2 February 2023 |access-date=January 11, 2018 |publisher=SpaceNews}} NASA confirmed (March 2018) that the changes{{clarify|date=February 2022}} made to the project had reduced its estimated life cycle cost to US$3.2 billion and that the Phase B decision{{clarify|date=February 2022}} was on track to begin on 11 April 2018.{{cite web |author=Foust |first=Jeff |date=March 28, 2018 |title=WFIRST work continues despite budget and schedule uncertainty |url=http://spacenews.com/wfirst-work-continues-despite-budget-and-schedule-uncertainty/ |url-status=live |archive-url=https://web.archive.org/web/20230202194506/http://spacenews.com/wfirst-work-continues-despite-budget-and-schedule-uncertainty/ |archive-date=2 February 2023 |access-date=April 3, 2018 |publisher=SpaceNews}}

In February 2018, the Trump administration's proposed an FY2019 budget that would have delayed the funding of the Roman (then called WFIRST), citing higher priorities{{clarify|date=February 2022}} within NASA and the increasing cost of this telescope.{{cite web |date=February 12, 2018 |title=FY 2019 budget estimates |url=https://www.nasa.gov/sites/default/files/atoms/files/nasa_fy_2019_budget_overview.pdf |access-date=February 12, 2018 |archive-date=24 August 2019 |archive-url=https://web.archive.org/web/20190824220543/https://www.nasa.gov/sites/default/files/atoms/files/nasa_fy_2019_budget_overview.pdf |url-status=live }} {{PD-notice}} The proposed defunding of the project was met with criticism by professional astronomers, who noted that the American astronomical community had rated Roman the highest-priority space mission for the 2020s in the 2010 Decadal Survey.{{cite news|last=Cofield|first=Calla|date=February 13, 2018|title=What Would it Mean for Astronomers if the WFIRST Space Telescope is Killed?|publisher=Space.com|url=https://www.space.com/39680-wfirst-space-telescope-cancellation-scientist-reactions.html|access-date=February 13, 2018|archive-date=31 August 2019|archive-url=https://web.archive.org/web/20190831085112/https://www.space.com/39680-wfirst-space-telescope-cancellation-scientist-reactions.html|url-status=live}}{{cite news|last=Overbye|first=Dennis|date=February 19, 2018|title=Astronomers' Dark Energy Hopes Fade to Gray|newspaper=The New York Times|url=https://www.nytimes.com/2018/02/19/science/nasa-dark-energy-wfirst.html|access-date=February 19, 2018|archive-date=13 September 2019|archive-url=https://web.archive.org/web/20190913095405/https://www.nytimes.com/2018/02/19/science/nasa-dark-energy-wfirst.html|url-status=live}} The American Astronomical Society expressed "grave concern" about the proposed defunding, and noted that the estimated lifecycle cost for Roman had not changed over the previous two years.{{cite web |author=Parriott |first=Joel |date=February 14, 2018 |title=American Astronomical Society Leaders Concerned with Proposed Cancellation of WFIRST |url=https://aas.org/posts/news/2018/02/aas-leaders-concerned-proposed-cancellation-wfirst |url-status=live |archive-url=https://web.archive.org/web/20180222043715/https://aas.org/posts/news/2018/02/aas-leaders-concerned-proposed-cancellation-wfirst |archive-date=22 February 2018 |access-date=February 21, 2018 |publisher=American Astronomical Society}} In agreement, Congress approved a FY2018 Roman budget on 22 and 23 March 2018 in excess of the administration's budget request for that year, stated that it "rejects the cancellation of scientific priorities recommended by the National Academy of Sciences decadal survey process", and directed NASA to develop new estimates of Roman's total and annual development costs.{{cite news |last=Brainard |first=Jeffrey |date=March 23, 2018 |title=Planetary science wins big in NASA's new spending plan |publisher=Science (journal) American Association for the Advancement of Science |url=https://www.science.org/content/article/planetary-science-wins-big-nasa-s-new-spending-plan |url-status=live |access-date=April 1, 2018 |archive-url=https://web.archive.org/web/20220315172036/https://www.science.org/content/article/planetary-science-wins-big-nasa-s-new-spending-plan |archive-date=15 March 2022}} The President of the United States announced he had signed the bill on 23 March 2018.{{cite news|url=https://www.aamc.org/advocacy/washhigh/highlights2018/488058/032318presidentsignsfy2018omnibuswith3billionnihincreaseboostfor.html|title=President Signs FY 2018 Omnibus with US$3 Billion NIH Increase, Boost for Other Health Programs|work=Tannaz Rasouli et al|publisher=Association of American Medical Colleges|date=March 23, 2018|access-date=April 1, 2018|archive-date=23 March 2018|archive-url=https://web.archive.org/web/20180323222550/https://www.aamc.org/advocacy/washhigh/highlights2018/488058/032318presidentsignsfy2018omnibuswith3billionnihincreaseboostfor.html|url-status=live}} NASA was funded via a FY2019 appropriations bill on 15 February 2019, with US$312 million for Roman, rejecting the President's reduced Budget Request and reasserting the desire for completion of Roman with a planning budget of US$3.2 billion.{{cite web |author=Wilkins |first=Ashlee |date=February 22, 2019 |title=Astronomical Sciences in the Final FY 2019 Spending Agreement |url=https://aas.org/posts/blog/2019/02/astronomical-sciences-final-fy-2019-spending-agreement |url-status=live |archive-url=https://web.archive.org/web/20190401213035/https://aas.org/posts/blog/2019/02/astronomical-sciences-final-fy-2019-spending-agreement |archive-date=1 April 2019 |access-date=April 1, 2019}}

In March 2019 the Trump administration again proposed to defund the Roman in its FY2020 budget proposal to Congress.{{cite web|url=https://www.nasa.gov/sites/default/files/atoms/files/fy2020_agency_fact_sheet.pdf|title=NASA FY2020 Budget Request|date=March 11, 2019|access-date=April 1, 2019|archive-date=15 March 2019|archive-url=https://web.archive.org/web/20190315185308/https://www.nasa.gov/sites/default/files/atoms/files/fy2020_agency_fact_sheet.pdf|url-status=live}} {{PD-notice}} In testimony on 27 March 2019, NASA Administrator Jim Bridenstine hinted that NASA would continue Roman after the James Webb Space Telescope, stating "WFIRST will be a critical mission when James Webb is on orbit".{{cite news |author=Foust |first=Jeff |date=March 28, 2019 |title=WFIRST faces funding crunch |publisher=SpaceNews |url=https://spacenews.com/wfirst-faces-funding-crunch/ |url-status=live |access-date=April 1, 2019 |archive-url=https://web.archive.org/web/20230202194506/https://spacenews.com/wfirst-faces-funding-crunch/ |archive-date=2 February 2023}} In a 26 March 2019, presentation to the National Academies' Committee on Astronomy and Astrophysics, NASA Astrophysics Division Director Paul L. Hertz stated that Roman "is maintaining its US$3.2 billion cost for now... We need US$542 million in FY2020 to stay on track". At that time, it was stated that Roman would hold its Preliminary Design Review (PDR) for the overall mission in October 2019 followed by a formal mission confirmation in early 2020.

NASA announced the completion of the Preliminary Design Review (PDR) on 1 November 2019, but warned that though the mission remained on track for a 2025 launch date, shortfalls in the Senate's FY2020 budget proposal for Roman threatened to delay it further.{{cite web|url=https://spacenews.com/wfirst-passes-preliminary-design-review/|title=WFIRST passes preliminary design review|last=Foust|first=Jeff|publisher=SpaceNews|date=November 11, 2019|access-date=March 14, 2021|archive-date=2 February 2023|archive-url=https://web.archive.org/web/20230202194507/https://spacenews.com/wfirst-passes-preliminary-design-review/|url-status=live}}

In April 2025, the second Trump administration proposed to cut funding for Roman again as part of its FY2026 budget draft. This was part of wider proposed cuts to NASA's science budget, down to US$3.9 billion from its FY2025 budget of US$7.5 billion.{{cite web |last1=Berger |first1=Eric |title=Trump White House budget proposal eviscerates science funding at NASA |url=https://arstechnica.com/space/2025/04/trump-white-house-budget-proposal-eviscerates-science-funding-at-nasa/ |website=Ars Technica |access-date=11 April 2025 |archive-url=https://web.archive.org/web/20250411141320/https://arstechnica.com/space/2025/04/trump-white-house-budget-proposal-eviscerates-science-funding-at-nasa/ |archive-date=11 April 2025 |date=11 April 2025 |url-status=live}}

File:High-Gain Antenna for Roman Space Telescope.jpg

The Roman project office is located at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and holds responsibility for overall project management. GSFC also leads the development of the Wide-Field Instrument, the spacecraft, and the telescope. The Coronagraphic Instrument is being developed at NASA's Jet Propulsion Laboratory in Pasadena, California. Science support activities for Roman are shared among Space Telescope Science Institute (Baltimore, Maryland), which is the Science Operations Center; the Infrared Processing and Analysis Center, Pasadena, California; and GSFC.

Four international partners, namely the French space agency CNES, European Space Agency (ESA), Japan Aerospace Exploration Agency (JAXA), and the Max Planck Institute for Astronomy have joined with NASA to provide various components and science support for Roman.{{cite web|title=NASA Astrophysics|last1=Hertz|first1=Paul|url=https://www.aip.org/sites/default/files/aipcorp/images/fyi/pdf/hertz-astro2020-kickoff-slides.pdf#page=48|date=July 15, 2019|access-date=September 14, 2019|archive-date=2 September 2019|archive-url=https://web.archive.org/web/20190902093726/https://www.aip.org/sites/default/files/aipcorp/images/fyi/pdf/hertz-astro2020-kickoff-slides.pdf#page=48|url-status=live}}{{cite news|url=https://spacenews.com/nasa-plans-to-have-wfirst-reviews-complete-by-april/|title=NASA plans to have WFIRST reviews complete by April|publisher=SpaceNews|last=Foust|first=Jeff|date=January 9, 2018|access-date=August 27, 2018|archive-date=2 February 2023|archive-url=https://web.archive.org/web/20230202194507/https://spacenews.com/nasa-plans-to-have-wfirst-reviews-complete-by-april/|url-status=live}}{{Cite web |last=Cowing |first=Keith |date=2022-12-25 |title=Assembly Begins On Roman Space Telescope Coronagraph Instrument Color Filter Assembly To Study Exoplanets |url=https://spaceref.com/science-and-exploration/assembly-begins-on-roman-space-telescope-coronagraph-instrument-color-filter-assembly-to-study-exoplanets/ |access-date=2023-06-12 |website=SpaceRef |language=en-US}} Beginning in 2016 NASA expressed interest in ESA contributions to the spacecraft, coronagraph and ground station support.{{cite web|title=WFIRST Programmatic Overview|url=https://conference.ipac.caltech.edu/wfirst2016/system/media_files/binaries/68/original/WFIRSTCA_Benford_rev2_web.pdf#page=5|last=Benford|first=Dominic|publisher=NASA|date=March 1, 2016|access-date=August 27, 2018|archive-date=27 August 2018|archive-url=https://web.archive.org/web/20180827195713/https://conference.ipac.caltech.edu/wfirst2016/system/media_files/binaries/68/original/WFIRSTCA_Benford_rev2_web.pdf#page=5|url-status=live}} {{PD-notice}} For the coronagraph instrument, contributions from Europe and Japan have been established. In 2018, a contribution from Germany's Max Planck Institute for Astronomy was under consideration, namely the filter wheels for the star-blocking mask inside the coronagraph.{{cite web|title=WFIRST Coronagraph Instrument (CGI) Status|url=https://exoplanets.nasa.gov/system/presentations/files/88_Zhao_WFIRST_CGI.pdf|last1=Zhao|first1=Feng|last2=Grady|first2=Trauger|publisher=Jet Propulsion Laboratory|date=July 29, 2018|access-date=August 28, 2018|archive-date=27 August 2018|archive-url=https://web.archive.org/web/20180827195358/https://exoplanets.nasa.gov/system/presentations/files/88_Zhao_WFIRST_CGI.pdf|url-status=live}} {{PD-notice}} In 2016, the Japanese space agency JAXA proposed to add a polarization module for the coronagraph, plus a polarization compensator. An accurate polarimetry capability on Roman may strengthen the science case for exoplanets and planetary disks, which shows polarization.{{cite web|url=https://www.naoj.org/Science/SubaruUM/SubaruUM2016/files/d3_1350_Yamada.pdf|title=WFIRST|last=Yamada|first=Toru|publisher=Subaru Telescope|date=January 10, 2017|access-date=August 30, 2018|archive-date=30 August 2018|archive-url=https://web.archive.org/web/20180830005257/https://www.naoj.org/Science/SubaruUM/SubaruUM2016/files/d3_1350_Yamada.pdf|url-status=live}}{{cite journal|url=https://repository.exst.jaxa.jp/dspace/handle/a-is/609734|title=WFIRST (Wide-Field Infrared Survey Telescope)|last1=Sumi|first1=Takahiro|last2=Yamada|first2=Toru|last3=Tamura|first3=Motohide|last4=Takada|first4=Masahiro|journal=第17回宇宙科学シンポジウム 講演集 |publisher=JAXA|language=ja|date=January 5, 2017|access-date=August 30, 2018|archive-date=30 August 2018|archive-url=https://web.archive.org/web/20180830005154/https://repository.exst.jaxa.jp/dspace/handle/a-is/609734|url-status=live}} Ground support will be provided by a new NASA station in White Sands, the Misada station in Japan and ESAs New Norcia station in Australia.{{cite web|url=https://roman.gsfc.nasa.gov/interactive/subparts/ground-antennas/|title=Ground Antennas|publisher=NASA|access-date=May 30, 2023}} {{PD-notice}}

In May 2018, NASA awarded a multi-year contract to Ball Aerospace to provide key components (the WFI Opto-Mechanical Assembly) for the Wide-Field Instrument on Roman.{{cite news|url=https://www.nasa.gov/press-release/nasa-awards-contract-for-space-telescope-mission-0|title=NASA Awards Contract for Space Telescope Mission|last=Brown|first=Katherine|date=May 23, 2018|publisher=NASA|access-date=October 9, 2018|archive-date=28 May 2018|archive-url=https://web.archive.org/web/20180528180108/https://www.nasa.gov/press-release/nasa-awards-contract-for-space-telescope-mission-0/|url-status=live}} {{PD-notice}} In June 2018, NASA awarded a contract to Teledyne Scientific and Imaging to provide the infrared detectors for the Wide-Field Instrument.{{cite news|url=https://www.nasa.gov/press-release/goddard/2018/nasa-awards-the-short-wave-infra-red-sensor-chip-assembly-for-wfirst|title=NASA Awards the Short Wave Infra-Red Sensor Chip Assembly for WFIRST|last=O'Carroll|first=Cynthia M.|date=June 15, 2018|publisher=NASA|access-date=November 14, 2018|archive-date=2 February 2023|archive-url=https://web.archive.org/web/20230202194508/https://www.nasa.gov/press-release/goddard/2018/nasa-awards-the-short-wave-infra-red-sensor-chip-assembly-for-wfirst/|url-status=live}} {{PD-notice}} On 30 November 2018, NASA announced it had awarded the contract for Optical Telescope Assembly to the Harris Corporation of Rochester, New York.

File:Roman phatSIM clean smaller.jpg|A simulated image of part of the Andromeda Galaxy

File:Wfirst-detail-annot.png|This simulated image showcases the red and infrared light of more than 50 million stars in Andromeda, as they would appear with WFIRST

File:Roman phatSIM context annotated.jpg|A composite figure shows the region of Andromeda covered by the Roman Space Telescope simulation. Roman would be able to image the main body of Andromeda in just a few pointings, surveying the galaxy nearly 1500 times faster than Hubble.

• {{annotated link|Wide-field Infrared Survey Explorer}}
• {{annotated link|James Webb Space Telescope}}
• {{annotated link|Spitzer Space Telescope}}
• {{annotated link|Xuntian}}
• Euclid - A European space telescope, also conducting a survey to study dark energy

{{Reflist}}

{{commons category|Nancy Grace Roman Space Telescope}}

• [http://wfirst.gsfc.nasa.gov/ Roman page at Goddard Space Flight Center site]
• [https://web.archive.org/web/20150214042451/https://www.ipac.caltech.edu/wfirst/ Roman Science Data Center page at the Infrared Processing and Analysis Center (IPAC)]
• [http://www.space.com/news/huge-telescopes-alien-planets-dark-energy-report-100813.html US$1.6 Billion Telescope Would Search Alien Planets and Probe Dark Energy] – Space.com
• [http://www.seti.org/weeky-lecture/wfirstafta-astrophysics-mission-bigger-and-better-exoplanets-0 The WFIRST/AFTA astrophysics mission: bigger and better for exoplanets] {{Webarchive|url=https://web.archive.org/web/20160405065231/http://www.seti.org/weeky-lecture/wfirstafta-astrophysics-mission-bigger-and-better-exoplanets-0 |date=5 April 2016 }}, Tom Greene
• {{cite web|url=http://sites.nationalacademies.org/xpedio/idcplg?IdcService=GET_FILE&dDocName=BPA_058306&RevisionSelectionMethod=Latest|title=Astro2010 Report Release Presentation|access-date=15 August 2010|archive-date=26 July 2011|archive-url=https://web.archive.org/web/20110726094422/http://sites.nationalacademies.org/xpedio/idcplg?IdcService=GET_FILE&dDocName=BPA_058306&RevisionSelectionMethod=Latest|url-status=dead}}
• {{YouTube|id=-HXYg_BWGpk|title=NASA/ Goddard – WFIRST: Uncovering the Mysteries of the Universe}} {{small|(min. 1:25)}} 30 May 2014
• {{YouTube|id=zkTHuqiH_1Y|title=WFIRST-AFTA: Coronograph Technology Development}} {{small|(min. 4:20)}} 16 March 2015
• {{YouTube|id=LbJpVHMV1m4|title=WFIRST: The Best of Both Worlds}} {{small|(min. 3:14)}} 18 February 2016

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