NASA’s SPHEREx mission, launched in March 2025, is a near-infrared space telescope mapping the entire sky in 102 color bands to study how the universe formed and evolved. By creating four full-sky surveys, it measures spectra from hundreds of millions of galaxies and stars, helping scientists probe cosmic inflation, galaxy growth, and the origins of water ice and organic molecules in space. SPHEREx also tracks dynamic events and identifies targets for telescopes like JWST. Its growing dataset, produced with simple, efficient technology, is set to become a major resource for understanding the early universe, cosmic structure, and the building blocks of life.
Long Version
Unveiling the Cosmos: NASA’s SPHEREx Mission and Its Quest to Map the Universe
In the ever-expanding field of astrophysics and cosmology, NASA’s SPHEREx mission stands as a groundbreaking space observatory dedicated to unraveling the universe’s deepest mysteries. Launched in March 2025, this near-infrared spacecraft is designed to conduct an all-sky survey, creating a comprehensive map of the sky in 102 different color bands. Officially known as the Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer, SPHEREx represents a pivotal advancement in space exploration, blending photometry and spectroscopy to gather unprecedented spectra and data from billions of celestial objects.
Mission Overview: A Spectral Imager for Cosmic History
SPHEREx is a NASA-led mission managed by the Jet Propulsion Laboratory (JPL) in collaboration with the California Institute of Technology (Caltech) and BAE Systems (formerly Ball Aerospace), among other partners, including institutions such as UC Irvine, Ohio State University, Harvard-Smithsonian Center for Astrophysics, Arizona State University, University of Arizona, Rochester Institute of Technology, Argonne National Laboratory, and Johns Hopkins University. As a space telescope operating in the near-infrared spectrum from 0.75 to 5.0 micrometers, it serves as a spectral imager capable of capturing detailed information about galaxies, stars, and other astronomical phenomena. The mission’s primary goal is to produce four complete all-sky maps over its planned two-year duration, surveying the entire sky every six months from a sun-synchronous polar orbit in low-Earth orbit. This orbit, at approximately 700 kilometers altitude with a 97-degree inclination, ensures consistent lighting conditions and optimal coverage for the spacecraft’s observations.
The telescope itself features a 20-centimeter diameter aperture and a wide 3.5° by 11° field of view, equipped with six 2K by 2K mercury cadmium telluride photodetector arrays using linear variable filters to achieve its spectroscopic capabilities. By employing no moving parts and a single observing mode, SPHEREx efficiently collects data through multiple exposures and precise spacecraft repointing, enabling it to detect over 450 million galaxies and more than 100 million stars within the Milky Way. This vast dataset will probe the origins of the universe, from the Epoch of Reionization—a period when the first stars and galaxies ionized the intergalactic medium—to the formation of modern cosmic structures. All collected data is made publicly available through the Infrared Processing and Analysis Center, fostering widespread scientific collaboration.
Scientific Objectives: Probing Inflation, Galaxy Formation, and the Building Blocks of Life
At the heart of SPHEREx’s science are three interconnected themes that address fundamental questions in cosmology and astrobiology. First, the mission aims to constrain the physics of inflation, the rapid expansion of the universe shortly after the Big Bang, by measuring non-Gaussianity in the large-scale structure of matter. Through redshifts and spatial clustering analysis in deep fields near the ecliptic poles, SPHEREx will survey vast cosmological volumes at low redshifts, providing insights into primordial fluctuations and potential deviations from standard inflationary models.
Second, it traces the cosmic history of galaxy formation by mapping the integrated light from stars and galaxies across billions of years. This includes studying stellar nurseries, where new stars emerge from dense molecular clouds, and examining how dark energy influences the large-scale structure of the universe. By charting the evolution of galaxies from their earliest stages, SPHEREx illuminates the processes that shaped the cosmos, including intra-halo light and the reionization epoch.
Third, as an Ices Explorer, SPHEREx investigates the abundance and composition of water ice, carbon dioxide, and organic molecules—key building blocks of life—in protoplanetary disks and molecular clouds. Measuring ice absorption spectra from over a million sources, the mission explores astrobiology themes, such as the delivery of biogenic materials to forming planets and the potential for exoplanet habitability. These observations could identify targets for follow-up studies with instruments like the James Webb Space Telescope or the Nancy Grace Roman Space Telescope (formerly WFIRST), enhancing our understanding of how life-essential elements originated in the universe.
Launch, Deployment, and Operational Milestones
SPHEREx lifted off on March 11, 2025 (March 12 UTC), aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base’s SLC-4E, sharing the ride with NASA’s PUNCH microsatellites. The launch marked a seamless deployment into its designated orbit, with the spacecraft achieving first light in April 2025 and commencing regular science operations on May 1, 2025. By December 2025, approximately nine months into the mission, SPHEREx has completed its first all-sky map and is progressing toward the second, capturing around 600 exposures daily for a total of 3,600 images across its detectors.
Early operations included ejecting the dust cover from the telescope in late March 2025, followed by initial imaging that revealed wide, multi-wavelength views of the sky. As of late 2025, the mission has contributed to real-time observations of dynamic events, such as the interstellar comet 3I/ATLAS, where SPHEREx’s infrared capabilities detected icy compositions and dust features alongside other telescopes. These efforts have yielded stunning preliminary results, including images of soot-like clouds in galactic regions captured on May 1, 2025, and spectral data on hydrogen halos, underscoring the observatory’s role in fast-moving astrophysical studies. Ongoing surveys continue to build a dataset that includes distant galaxies whose light has traveled 10 billion years to reach Earth.
Technological Innovations and Collaborative Efforts
The mission’s success hinges on innovative engineering, including its cryogenic test chamber contributions from the Korea Astronomy and Space Science Institute and the robust design by BAE Systems. SPHEREx’s ability to perform low-resolution spectroscopy across the near-infrared band allows for efficient data collection without complex mechanisms, making it a cost-effective MIDEX-class explorer with a total mission cost around $395–427 million, including launch. Technologies adapted from Earth satellites and interplanetary spacecraft further enhance its reliability and performance.
Principal Investigator James Bock at Caltech leads the scientific direction, ensuring the data archive—expected to include over a billion galaxies, hundreds of millions of stellar spectra, and a million ice absorption profiles—serves as a legacy resource for the global astronomy community. This archive complements surveys from missions like Euclid and Roman, offering unique insights into weak gravitational lensing, redshift distributions, and the epoch of reionization.
Future Implications: A Legacy for Astrophysics and Beyond
As SPHEREx continues its survey through 2027, it promises to transform our understanding of the universe’s evolution, from inflationary origins to the distribution of life-enabling ices. By mapping the sky with unparalleled spectral resolution, the mission not only advances cosmology but also supports exoplanet research and astrobiology, potentially guiding future explorations for habitable worlds.
In an era of rapid space advancements, SPHEREx exemplifies NASA’s commitment to innovative, data-rich missions that push the boundaries of knowledge. Its findings, already hinting at new cosmic phenomena, will undoubtedly inspire generations of scientists and deepen humanity’s grasp of our place in the stars.
