The SPHEREx Satellite Mission
James J. Bock, Asad M. Aboobaker, Joseph Adamo, Rachel Akeson, John M. Alred, Farah Alibay, Matthew L. N. Ashby, Yoonsoo P. Bach, Lindsey E. Bleem, Douglas Bolton, David F. Braun, Sean Bruton, Sean A. Bryan, Tzu-Ching Chang, Shuang-Shuang Chen, Yun-Ting Cheng, James R. Cheshire, Yi-Kuan Chiang, Jean Choppin de Janvry, Samuel Condon, Walter R. Cook, Asantha Cooray, Brendan P. Crill, Ari J. Cukierman, Olivier Doré, C. Darren Dowell, Gregory P. Dubois-Felsmann, Tim Eifler, Spencer Everett, Beth E. Fabinsky, Andreas L. Faisst, James L. Fanson, Allen H. Farrington, Tamim Fatahi, Candice M. Fazar, Richard M. Feder, Eric H. Frater, Henry S. Grasshorn Gebhardt, Utkarsh Giri, Tatiana Goldina, Varoujan Gorjian, Salman Habib, William G. Hart, Chen Heinrich, Joseph L. Hora, Zhaoyu Huai, Howard Hui, Young-Soo Jo, Woong-Seob Jeong, Jae Hwan Kang, Miju Kang, Branislav Kecman, Chul-Hwan Kim, Jaeyeong Kim, Minjin Kim, Young-Jun Kim, Yongjung Kim, J. Davy Kirkpatrick, Yosuke Kobayashi, Phil M. Korngut, Elisabeth Krause, Bomee Lee, Ho-Gyu Lee, Jae-Joon Lee, Jeong-Eun Lee, Carey M. Lisse, Giacomo Mariani, Daniel C. Masters, Philip D. Mauskopf, Gary J. Melnick, Mary H. Minasyan, Jordan Mirocha, Hiromasa Miyasaka, Anne Moore, Bradley D. Moore, Giulia Murgia, Bret J. Naylor, Christina Nelson, Chi H. Nguyen, Hien T. Nguyen, Jinyoung K. Noh, Stephen Padin, Roberta Paladini, Sung-Joon Park, Konstantin I. Penanen, Dustin S. Putnam, Jeonghyun Pyo, Nesar Ramachandra, Keshav Ramanathan, Zafar Rustamkulov, Daniel J. Reiley, Eric B. Rice, Jennifer M. Rocca, Ji Yeon Seok, Roger Smith, Jeremy Stober, Sara Susca, Harry I. Teplitz, Michael P. Thelen, Volker Tolls
Abstract
Abstract Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer (SPHEREx), a NASA Explorer satellite launched on 2025 March 11, is carrying out the first all-sky near-infrared spectral survey. The satellite observes in 102 spectral bands from 0.75 to 5.0 μ m with a resolving power ranging from λ /Δ λ = 35–130 in 6 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mrow> <mml:mi>.</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>″</mml:mi> </mml:mrow> </mml:mover> </mml:math> 2 pixels. The observatory obtains a 5 σ depth of 19.5–19.9 AB mag for 0.75 < λ < 3.8 μ m with λ /Δ λ ∼ 40 and 17.8–18.8 AB mag for 3.8 < λ < 5.0 μ m with λ /Δ λ ∼ 120 after mapping the full sky four times over two years. Scientifically, SPHEREx will produce a large galaxy redshift survey over the full sky to constrain the amplitude of inflationary non-Gaussianity. The observations will produce two deep spectral maps near the ecliptic poles that use intensity mapping to probe the evolution of galaxies over cosmic history. By mapping the depth of infrared absorption features over the Galactic plane, SPHEREx will comprehensively survey the abundance and composition of water and other biogenic ice species in the interstellar medium. The project will release initial data rapidly in the form of spectral images, and specialized data products over the life of the mission as the surveys proceed. The science team will also produce spectral catalogs of planet-bearing and low-mass stars, solar system objects, and galaxy clusters three years after launch. We describe the design of the instrument and spacecraft, which flow from the core science requirements. Finally, we present an initial evaluation of the satellite’s in-flight performance and key characteristics.