From the formation of planets to the growth of black holes at the centre of galaxies, PRIMA (PRobe far-Infrared Mission for Astrophysics) is set to lift the veil on some of the most mysterious phenomena in the cold universe, by observing them in far-infrared light. France is contributing to the mission with PRIMAger, an imaging camera supplied by CNES with the French atomic energy and alternative energies commission CEA and the national scientific research centre CNRS.

Project in brief

While space-based astronomy is bringing new insights into our universe every day, there are still places that remain shrouded in mystery. Among these are the very cold objects visible in the far-infrared portion of the spectrum, like newly forming planets or the interstellar medium.

Selected in September 2026 for NASA’s Astrophysics Probe Explorer (APEX) Announcement of Opportunity, PRIMA (PRobe far-Infrared Mission for Astrophysics) will continue on from the Herschel space telescope mission.

The PRIMA mission’s three primary science goals are to:

• Characterize the evolution of stellar dust inside ancient galaxies to determine the origin of the peak of star formation 10 billion years ago
• Gain a clearer understanding of how protoplanetary disks form, notably by studying water transport
• Study how galaxies and their supermassive black holes have co-evolved over cosmic time

Built around a telescope with a mirror spanning 1.8 metres cooled to 4.5K, PRIMA will have advanced cryogenics, making it more sensitive and capable of mapping the universe faster than its predecessors.

One of PRIMA’s main missions will be to observe an era of the universe that is still poorly understood, when it was 5 to 10 billion years old [current estimates put its age at 13.8 billion years]. This period, also known as the intermediate universe, was the golden age of star formation. It is precisely PRIMA’s ability to survey this era that sets it apart from its forerunners. Like Herschel and the James Webb Space Telescope (JWST) before it, PRIMA will probe the interstellar and cold intergalactic medium in the far-infrared. But where JWST senses frequencies between 2 and 28 microns, PRIMA’s increased sensitivity to temperatures close to absolute zero—i.e., –273.15°C—make it an ideal candidate for detecting wavelengths of a few tens to several hundred microns.

To achieve such unprecedented levels of sensitivity, the mission will be carrying two complementary instruments with kinetic inductance detector (KID) arrays cooled to –273.15°C (100 mK): FIRESS (Far Infrared Enhanced Survey Spectrometer), supplied by JPL, and the PRIMAger imaging camera.

After launch, PRIMA will be placed into orbit at the L2 Lagrange point 1.5 million kilometres from Earth, in the direction away from the Sun. The mission is planned to last at least five years, with 75% of its observing time open to the international scientific community.

CNES’s role

France is the leading international contributor to the PRIMA mission. Its contribution notably includes delivery to the Jet Propulsion Laboratory (JPL) of the PRIMAger imaging camera. This innovative cooled thermal camera, with hyperspectral and polarimetric channels, is being developed under CNES’s supervision by a European consortium comprising:

• CNRS, through its LAM astrophysics laboratory in Marseille, is responsible for PRIMAger system activities, for its optical and mechanical architecture, and for construction of the opto-mechanical structure and instrument integration.
• CEA, the French atomic energy and alternative energies commission, is science lead and in charge of defining the thermal architecture and developing and delivering both the Thermal Link Assembly (TLA) and the cryogenic test unit that will serve to verify PRIMAger on the ground.
• The Netherlands Institute for Space Research (SRON) is responsible for development and delivery of the focal planes and their detector modules.
• Cardiff University is responsible for development and delivery of PRIMAger’s filters.

Contacts

Project Lead
Florent Canourgues
E-mail: florent.canourgues at cnes.fr

Head of Universe Sciences Programme
Olivier La Marle
E-mail: olivier.la-marle at cnes.fr