NASA SPHEREx maps Milky Way ice

NASA released the first broad SPHEREx results on April 15, showing interstellar ice across giant molecular clouds in the Milky Way and tying the detections to a study in *The Astrophysical Journal*. The observations cover regions more than 600 light-years across and focus on Cygnus X, a star-forming complex in the galactic plane. NASA and the mission team said the telescope detected the signatures of water ice as well as carbon dioxide and carbon monoxide ice using infrared spectroscopy. The release marks one of the first science showcases from SPHEREx since the observatory began regular science operations in May 2025. ### What did SPHEREx actually map? NASA said SPHEREx mapped the spatial distribution of interstellar ice inside giant molecular clouds, rather than only spotting ice along isolated lines of sight toward individual stars. Lead author Joseph Hora of the Center for Astrophysics | Harvard & Smithsonian said the diffuse background light in the galactic plane let SPHEREx see how ices are spread through entire dust clouds “in incredible detail.” (nasa.gov) The April 15 image release highlighted Cygnus X, one of the Milky Way’s most active star-forming regions. NASA’s caption said water ice appears in bright blue and polycyclic aromatic hydrocarbons, a dust-related molecule, appear in orange in the SPHEREx view. ### Why is Cygnus X the first showcase? (nasa.gov) Cygnus X sits in a crowded part of the Milky Way where stars, gas and dust are concentrated, making it a useful test case for wide-field infrared mapping. NASA said the densest ice regions line up with the densest dust regions, supporting the idea that interstellar ice forms on the surfaces of tiny dust grains and is shielded there from ultraviolet radiation from newborn stars. (nasa.gov) Phil Korngut, instrument scientist for SPHEREx at Caltech and a coauthor on the study, said the frozen structures are like “interstellar glaciers” that could supply water to new solar systems forming in the region. That interpretation was presented by NASA and the mission team as part of the study’s implications for how water-bearing material is stored before stars and planets form. (jpl.nasa.gov) ### How is SPHEREx different from Webb or Spitzer? NASA said telescopes including the James Webb Space Telescope and the retired Spitzer Space Telescope have detected icy molecules across the galaxy before, but SPHEREx was designed to find such molecules across the whole sky through a large-scale spectral survey. The observatory sees in 102 infrared colors, which NASA says lets it distinguish chemical signatures tied to different molecules and dust components. (nasa.gov) The mission’s broader job is larger than this one map. NASA’s press materials say SPHEREx will build an all-sky spectral map to study the distribution of galaxies in 3D and trace the abundance of water and other life-related ingredients in the Milky Way. ### When did the mission start producing science data? NASA launched SPHEREx on March 11, 2025, and said the spacecraft began regular science operations on May 1, 2025. (nasa.gov) The observatory takes about 3,600 images per day and is scheduled to spend about two years surveying the sky, completing a full-sky view every six months as its orbit and Earth’s motion around the Sun shift its field of view. (jpl.nasa.gov) A NASA visualization released on March 30, 2026, showed early all-sky mosaic images assembled from observations collected between May and December 2025. NASA said those broader maps already show dust, gas, stars and galaxies, while other SPHEREx wavelengths reveal water ice, carbon dioxide ice and carbon monoxide ice across the Milky Way. ### What comes next from this telescope? (jpl.nasa.gov) The April 15 paper is one of the first published science results from the mission, not the endpoint of the survey. NASA said SPHEREx will continue its planned 25 months of survey operations, building repeated all-sky coverage that can be used to extend ice maps beyond Cygnus X and compare different molecular-cloud environments across the galaxy. That continuing survey is also expected to feed future follow-up work by teams using SPHEREx data and by other observatories, including Webb, on selected targets. (svs.gsfc.nasa.gov) (jpl.nasa.gov)