NASA has selected a new far-infrared space telescope, PRIMA, to move into detailed design work, the agency announced this week, setting up a 2033 launch for a mission that scientists say will help explain how planets, galaxies and black holes came to be.
PRIMA, short for the PRobe far-Infrared Mission for Astrophysics, is the first mission chosen for NASA's new Probe Explorers class, an addition to the long-running Explorers Program that sits between small, low-cost missions and NASA's largest flagship observatories. The project's cost is capped at $1.2 billion, not counting launch and other non-project expenses, and NASA's Jet Propulsion Laboratory, managed by Caltech, will build and operate the spacecraft.
The observatory will carry a 1.8-meter telescope cooled to within a few degrees of absolute zero, equipped with two instruments: an imaging polarimeter called PRIMAger and a high-resolution spectrometer named FIRESS. Together they are designed to detect far-infrared light, wavelengths too long for the James Webb Space Telescope and too short for ground-based radio telescopes, that reveal dust-shrouded regions of star and planet formation invisible to other observatories. Mission planners say the data should help trace how water arrived on rocky planets, how galaxies and their central black holes grow together over cosmic time, and how heavy elements accumulate in interstellar dust.
International project, longer runway
The mission now enters Phase B, the stage where NASA finalizes engineering designs before committing to full-scale construction. Space agencies in Canada, France, Germany, Italy, Japan, South Korea and the United Kingdom are contributing hardware and expertise, alongside NASA's Goddard and Marshall spaceflight centers. Caltech's Infrared Processing and Analysis Center will serve as the mission's science operations center.
"PRIMA represents a giant leap for far-infrared astronomy."
— Ray Jayawardhana, Caltech president
NASA science chief Nicky Fox said the telescope would "unveil the obscure across cosmic time" to help researchers understand the formation of planets, stars and black holes. If confirmed for full development, PRIMA would launch on a rocket yet to be selected, for a primary mission expected to last five years.
The Probe Explorers class was created to give astronomers access to mid-sized missions faster than the decade-plus timelines typical of flagship telescopes, while still tackling questions too ambitious for the smallest Explorer-class satellites. NASA and its partners now begin detailed design review, with confirmation of the full $1.2 billion budget expected once Phase B engineering work concludes.