NASA announced on Sept. 23, 2026, that PRIMA (PRobe far-Infrared Mission for Astrophysics) was advancing to Phase B, the stage that develops preliminary design and technology for the mission. The space telescope would be the first in a new NASA astrophysics mission class called Probe Explorers, part of the agency's Explorers Program. NASA said the mission was subject to a confirmation review based on technical, programmatic and cost performance before any decision to begin implementation in Phase C.

If confirmed, PRIMA's project cost was capped at $1.2 billion, excluding launch and other non-project costs. The observatory was targeted to launch in 2033 for a planned five-year mission. With a 5.9-foot telescope, NASA said PRIMA would conduct deep, sensitive surveys of the universe in far-infrared light, helping bridge the gap between existing infrared observatories such as the James Webb Space Telescope and radio telescopes. NASA said the mission was intended to study questions including the origins of planets outside our solar system, the growth of galaxies and their black holes, and the buildup of dust and heavy elements over cosmic time.

NASA's Jet Propulsion Laboratory in Southern California was named to manage the mission, with partners including Goddard Space Flight Center in Greenbelt, Maryland, and Marshall Space Flight Center in Huntsville, Alabama. NASA listed international contributions from CNES, ASI, DLR, the Canadian Space Agency, KASI/KASA, JAXA and the UK Space Agency. The release, updated Sept. 24, 2026, to reflect current international partners, said the Probe Explorers class followed a recommendation in the National Academies' 2020 Decadal Survey.