SPHEREx

File:SPHEREx March2022 Update.jpg

SPHEREx will use a spectrophotometer to perform an all-sky survey that will measure near-infrared spectra from 0.75 to 5.0 micrometers. It will employ a single instrument with a single observing mode and no moving parts to map the entire sky (in 96

different color bands, far exceeding the color resolution of previous all-sky maps) four times during its nominal 25-month mission; the crucial technology is a linear variable filter,{{cite web|url=http://spherex.caltech.edu/Science.html|title=SPHEREx Science|publisher=Caltech|date=2018|access-date=25 April 2018|archive-date=2 March 2019|archive-url=https://web.archive.org/web/20190302211637/http://spherex.caltech.edu/Science.html|url-status=dead}} {{PD-notice}} as demonstrated by LEISA on New Horizons.

It will classify galaxies according to redshift accuracy, categorizing approximately 450 million galaxies and fitting measured spectra to a library of galaxy templates. Specifically, SPHEREx will probe signals from the intra-halo light and from the epoch of reionization. It would explore what drove the early universe inflation, explore the origin and history of galaxies, and explore the origin of water in planetary systems.[https://www.science.org/content/article/missions-probe-exoplanets-galaxies-and-cosmic-inflation-vie-250-million-nasa-slot Missions to probe exoplanets, galaxies, and cosmic inflation vie for US$250 million NASA slot] Daniel Clery, Science Magazine, 16 August 2017{{Cite news|title=Proposed Astrophysics Mission to Conduct the First Infrared Spectral Survey of the Entire Sky|date=28 August 2017|first=Tomasz|last=Nowakowski|publisher=PHYS.ORG - Astronomy|url=https://ridl.cfd.rit.edu/products/press/CfD%20News%20Articles/Proposed%20astrophysics%20mission%20to%20conduct%20the%20first%20infrared%20spectral%20survey%20of%20the%20entire%20sky.pdf|url-status=live|archive-url=https://web.archive.org/web/20181214005242/http://www.astrowatch.net/2017/08/proposed-astrophysics-mission-to.html |archive-date=14 December 2018}}

SPHEREx will complement the Euclid and planned Nancy Grace Roman Space Telescope spectroscopic surveys. High precision redshift information of foreground galaxies provided by SPHEREx in correspondence with weak gravitational lensing measurements of background galaxies from Euclid and Nancy Grace Roman Space Telescope will allow direct measurement of the dark matter distribution surrounding the foreground galaxies.{{cite arXiv |last1=Doré|first1=Olivier |last2=Bock|first2=Jamie |last3=Ashby|first3=Matthew |last4=Capak|first4=Peter |last5=Cooray|first5=Asantha |last6=de Putter|first6=Roland |last7=Eifler |first7=Tim |last8=Flagey|first8=Nicolas |last9=Gong|first9=Yan |last10=Habib|first10=Salman |last11=Heitmann|first11=Katrin|author11-link=Katrin Heitmann|date=2015-03-25|title=Cosmology with the SPHEREX All-Sky Spectral Survey|class=astro-ph.CO|eprint=1412.4872}} The SPHEREx low redshift survey allows its measurement of inflationary parameters to be mostly independent, thus providing a new line of evidence.

File:SPHEREx Outer Photon Shield.jpg

File:SPHEREx telescope and detectors.jpg

The triple mirror telescope has an aperture diameter of 20 centimeters with a {{nobr|3.5° × 11°}} field of view and six {{nobr|2K × 2K}} mercury cadmium telluride (HgCdTe) photodetector arrays.{{cite web|title=SPHEREx Official Website |url=https://spherex.caltech.edu/index.html |url-status=dead |archive-url=https://web.archive.org/web/20220307182425/http://spherex.caltech.edu/index.html |archive-date=2022-03-07 |access-date=2020-10-06 |website=spherex.caltech.edu}} {{PD-notice}}{{cite web |title=SPHEREx instrument |url=https://spherex.caltech.edu/Instrument.html |access-date=25 March 2022 |archive-date=13 January 2022 |archive-url=https://web.archive.org/web/20220113020348/https://spherex.caltech.edu/Instrument.html |url-status=dead }} {{PD-notice}} Each {{nobr|2K × 2K}} focal-plane array is covered with a linear variable filter, providing narrow-band response with a band center that varies along one axis of the array. SPHEREx obtains spectra through multiple exposures, placing a given source at multiple positions in the field of view, where it is measured at multiple wavelengths by repointing the spacecraft.

The SPHEREx spacecraft and telescope were provided by BAE Systems Inc. Space & Mission Systems division (previously Ball Aerospace & Technologies) while the payload was developed by Caltech and NASA's Jet Propulsion Laboratory. The Korea Astronomy and Space Science Institute supplied a non-flight cryogenic test chamber.{{Cite web|url=https://rocketrundown.com/spacex-wins-98-million-nasa-spherex-launch-contract/|title=SpaceX wins $98 million NASA SPHEREx launch contract|date=8 February 2021}}{{cite web |url=https://www.jpl.nasa.gov/missions/spherex |title=Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer |work=JPL |publisher=NASA |access-date=7 July 2021}} {{PD-notice}}{{cite web | url=https://www.ball.com/newswire/article/124112/ball-aerospace-supports-critical-design-review-of-nasas-spherex-mission | title=Ball Aerospace Supports Critical Design Review of NASA's SPH }}

File:SPHEREx-PUNCH Encapsulation (KSC-20250227-PH-BNF01 0004).jpg

The SPHEREx proposal was submitted to NASA on 19 December 2014, and it was selected for further conceptual development (Phase A) on 30 July 2015 for the Small Explorer program (SMEX).[http://spherex.caltech.edu/News.html SPHEREx News] {{Webarchive|url=https://web.archive.org/web/20190307052306/http://spherex.caltech.edu/News.html |date=7 March 2019 }} SPHEREx, Caltech {{PD-notice}}{{cite web|url=https://www.nasa.gov/press-release/nasa-selects-proposals-to-study-neutron-stars-black-holes-and-more|title=NASA Selects Proposals to Study Neutron Stars, Black Holes and More|author=Karen Northon|publisher=NASA|date=30 July 2015}} {{PD-notice}} The detailed concept study report was submitted to NASA on 19 July 2016, but it was not selected for SMEX. An enhanced version of SPHEREx was submitted on 15 December 2016 as a Medium-Class Explorer (MIDEX), and it was selected as a finalist in August 2017, along two other competing missions: Arcus, and Fast Infrared Exoplanet Spectroscopy Survey Explorer (FINESSE). Each team received US$2 million to refine their mission concepts over nine-months.

SPHEREx was selected as the winner in February 2019, and the mission was approved to proceed with construction and launch. Medium-Class Explorer mission costs are capped at US$250 million, not including the launch vehicle. As of April 2020, the preliminary total cost of the mission is approximately US$395 million to US$427 million.{{cite web|url=https://www.gao.gov/assets/710/706505.pdf|title=GAO-20-405, NASA: Assessments of Major Projects|page=45|publisher=Government Accountability Office (GAO)|date=29 April 2020|access-date=30 April 2020}} {{PD-notice}} The 2020 estimates include the costs of the launch vehicle and NASA reserves that are not part of the cost cap.

File:PIA26280-NASA-SPHEREx-FirstImages-20250327.png

On 7 January 2021, NASA announced that the mission has entered Phase C, which means that the early design plans have been approved and teams can begin the final design and assemble hardware and software; and that launch is expected between June 2024 and April 2025.{{Cite web|url=https://www.cnn.com/2021/01/07/world/nasa-spherex-telescope-scn-trnd/index.html|title = New NASA space telescope will explore the Big Bang|website = CNN| date=7 January 2021 }} On 4 February 2021, NASA announced they had selected the SpaceX Falcon 9 to launch the spacecraft, and total cost of the launch would be US$98.8 million.{{cite news|last1=Potter|first1=Sean|title=NASA Awards Launch Services Contract for SPHEREx Astrophysics Mission|url=https://www.nasa.gov/press-release/nasa-awards-launch-services-contract-for-spherex-astrophysics-mission|access-date=4 February 2021|publisher=NASA|date=4 February 2021}} {{PD-notice}} In August 2022 NASA announced that the 4 microsatellites of the PUNCH constellation would be launched as rideshare payloads together with SPHEREx.{{cite web |last=Interrante |first=Abbey |url=https://blogs.nasa.gov/punch/2022/08/03/punch-announces-rideshare-with-spherex-and-new-launch-date/ |title=PUNCH Announces Rideshare with SPHEREx and New Launch Date |date=3 August 2022 |access-date=3 August 2022 |work=NASA}} The mission launched on 12 March 2025.{{cite news|agency=Associated Press |title=Nasa's new Spherex telescope lifts off to map cosmos in unprecedented detail |newspaper=The Guardian | date=12 March 2025 | url=https://www.theguardian.com/science/2025/mar/12/nasas-spherex-telescope-launch}} First light was on April 2025.{{Cite web |date=2025-04-01 |title=NASA’s SPHEREx Takes First Images, Preps to Study Millions of Galaxies - NASA |url=https://www.nasa.gov/missions/spherex/nasas-spherex-takes-first-images-preps-to-study-millions-of-galaxies/ |access-date=2025-05-03 |language=en-US}} Regular science operation started on 1 May 2025.{{Cite web |date=2025-05-01 |title=NASA’s SPHEREx Space Telescope Begins Capturing Entire Sky |url=https://www.jpl.nasa.gov/news/nasas-spherex-space-telescope-begins-capturing-entire-sky/ |access-date=2025-05-03 |website=NASA Jet Propulsion Laboratory (JPL) |language=en-US}}

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• [http://surveygizmoresponseuploads.s3.amazonaws.com/fileuploads/15647/4139225/235-e415ba848b86dcb8e980378f1b185c4b_StevensDanielJ.pdf Exoplanet Science with SPHEREx’s All-Sky Spectro-photometric Survey in the Near-Infrared] (PDF)

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