SPHEREx: An all-sky NIR spectral survey

Phillip M. Korngut, James J. Bock, Rachel Akeson, Matthew Ashby, Lindsey Bleem, Justin Boland, Douglas Bolton, Samuel Bradford, David Braun, Sean Bryan, Peter Capak, Tzu Ching Chang, Andrew Coffey, Asantha Cooray, Brendan Crill, Olivier Doré, Tim Eifler, Chang Feng, Salman Habib, Katrin HeitmannShoubaneh Hemmati, Christopher Hirata, Woong Seob Jeong, Minjin Kim, Davy Kirkpatrick, Theresa Kowalkowski, Elisabeth Krause, Carey Lisse, Philip Mauskopf, Daniel Masters, James McGuire, Gary Melnick, Hein Nguyen, Hooshang Nayyeri, Karin Oberg, Roland Deputter, William Purcell, Jennifer Rocca, Marcus Runyan, Karin Sandstrom, Roger Smith, Yong Seon Song, Nathaniel Stickley, Jeremy Stober, Sara Susca, Harry Teplitz, Volker Tolls, Stephen Unwin, Michael Werner, Rogier Windhorst, Michael Zemcov

Research output: Chapter in Book/Report/Conference proceedingConference contribution

19 Scopus citations


SPHEREx, a mission in NASA's Medium Explorer (MIDEX) program recently selected for Phase-A implementation, is an all-sky survey satellite that will produce a near-infrared spectrum for every 6 arcsecond pixel on the sky. SPHEREx has a simple, high-heritage design with large optical throughput to maximize spectral mapping speed. While the legacy data products will provide a rich archive of spectra for the entire astronomical community to mine, the instrument is optimized for three specific scientific goals: to probe inflation through the imprint primordial non-Gaussianity left on today's large-scale cosmological structure; to survey the Galactic plane for water and other biogenic ices through absorption line studies; and to constrain the history of galaxy formation through power spectra of background fluctuations as measured in deep regions near the ecliptic poles. The aluminum telescope consists of a heavily baffled, wide-field off-axis reflective triplet design. The focal plane is imaged simultaneously by two mosaics of H2RG detector arrays separated by a dichroic beamsplitter. SPHEREx assembles spectra through the use of mass and volume efficient linear variable filters (LVFs) included in the focal plane assemblies, eliminating the need for any dispersive or moving elements. Instead, spectra are constructed through a series of small steps in the spacecraft attitude across the sky, modulating the location of an object within the FOV and varying the observation wavelength in each exposure. The spectra will cover the wavelength range between 0.75 and 5.0 μm at spectral resolutions ranging between R=35 and R=130. The entire telescope is cooled passively by a series of three V-groove radiators below 80K. An additional stage of radiative cooling is included to reduce the long wavelength focal plane temperature below 60K, controlling the dark current. As a whole, SPHEREx requires no new technologies and carries large technical and resource margins on every aspect of the design.

Original languageEnglish (US)
Title of host publicationSpace Telescopes and Instrumentation 2018
Subtitle of host publicationOptical, Infrared, and Millimeter Wave
EditorsGiovanni G. Fazio, Howard A. MacEwen, Makenzie Lystrup
ISBN (Print)9781510619494
StatePublished - 2018
EventSpace Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave - Austin, United States
Duration: Jun 10 2018Jun 15 2018

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherSpace Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave
Country/TerritoryUnited States


  • All Sky survey
  • Biogenic ices
  • Cosmology
  • Extragalactic background light
  • Linear variable filters
  • Near infrared

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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