SPHEREx Mission Releases First Infrared All-Sky Map After March Launch

The Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer, known by its acronym SPHEREx, successfully transmitted its inaugural infrared map of the entire celestial sphere on December 18, 2025. This milestone follows the mission's launch in March 2025, which is designed to probe the cosmos using both optical and near-infrared light detection capabilities. The initial dataset, comprising data gathered across 102 distinct wavelengths, has been made accessible to the scientific community via the NASA/IPAC Infrared Science Archive, hosted at the California Institute of Technology (Caltech).

The primary operational phase for the observatory is slated to span two years, during which it intends to systematically observe the entirety of the sky. This comprehensive survey is projected to yield crucial data pertaining to more than 450 million galaxies and an estimated 100 million stars residing within the Milky Way. The scientific imperative behind the SPHEREx mission centers on resolving fundamental cosmological questions, particularly concerning the influence of cosmic inflation on the subsequent distribution of galaxies in the universe following the Big Bang.

Formal scientific observations commenced in May 2025, leading directly to the completion of the first all-sky mosaic in December 2025, a task accomplished through the daily capture and processing of approximately 3,600 individual images. Shawn Domagal-Goldman, the director of the Astrophysics Division at NASA Headquarters, underscored the substantial scientific yield realized from this initial six-month observational period. The visual representation of this first infrared map employs a color-coding scheme to render invisible infrared wavelengths intelligible: intensely hot hydrogen gas is depicted in blue tones, interstellar cosmic dust in shades of red, while stars are visualized using combinations of green, blue, and white.

SPHEREx achieves this spectral separation through the deployment of six specialized detectors, each equipped with a unique filter system engineered to partition the incoming light into 102 discrete wavelength bins. Project manager Beth Fabinsky compared the telescope's sophisticated multicolor detection apparatus to the complex visual processing capabilities found in a mantis shrimp. This new observatory distinguishes itself from preceding infrared surveys, such as NASA's Wide-field Infrared Survey Explorer (WISE), through a significantly greater number of observed spectral colors and a broader field of view. The collected spectral information is intended to facilitate the construction of the first truly three-dimensional distance map of the observable cosmos by precisely measuring the distances to the cataloged galaxies.

The mission plan includes executing three subsequent full scans of the sky, the data from which will be integrated with the existing information to enhance measurement sensitivity, thereby providing deeper insights into phenomena that occurred in the universe's earliest moments. The total financial commitment for the SPHEREx project, encompassing all mission phases from inception through completion, is currently estimated to be around USD 488 million. The successful deployment and initial data release confirm the operational readiness of the instrument suite, which is critical for identifying faint, distant objects whose light has been stretched into the infrared by the expansion of the universe.