Institute of research into the fundamental laws of the Universe

Description of the PRIMA mission

The PRIMA project is an innovative space observatory with a 1.8-metre telescope designed to study far-infrared wavelengths. It bridges the gap between existing infrared observatories, such as NASA's James Webb Space Telescope (JWST), and ground-based radio telescopes.

The project is based on two major scientific instruments:

• FIRESS (Far InfraRed Spectrometer System), an ultra-sensitive spectrometer covering a range from 25 to 80 microns, capable of low-resolution spectroscopy (R~200) for broad observations and medium-resolution (R~5000) for more detailed studies. Developed by the Jet Propulsion Laboratory (JPL) in Pasadena, this instrument will enable cosmic phenomena to be observed with great precision.
• PRIMAger, a multi-band spectrophotometric imager/polarimeter optimised for wavelengths between 25 and 300 microns. It will offer two bands: the first, hyperspectral (25-80 microns, R~10), and the second, including polarimetric capabilities (80-300 microns). This development is the fruit of an international collaboration between the LAM, the CEA (Paris-Saclay and Grenoble sites) and the SRON (Netherlands).

Operating in the far infrared, PRIMA's success is based on advanced cryogenic technologies (operating temperature at 4.5 K), enabling exceptionally sensitive observations.

PRIMA mission objectives

PRIMA's scientific objectives are vast and include:

• The co-evolution of galaxies and supermassive black holes through infrared observation of the dynamic processes that link them.
• The study of the formation of the first heavy elements and dust grains in the early universe, providing crucial information on the chemical evolution of the universe.
• The analysis of proto-planetary disks, making it possible to determine chemical abundances and to compare these data with the atmospheres of exoplanets, in order to better understand the role of water and other compounds in the formation of planets.
• The study of small bodies in the Solar System, in particular objects in the Kuiper Belt, for which PRIMA will be able to observe sizes between 35 and 80 km, inaccessible to previous missions such as Spitzer or Herschel.
• A complete hyperspectral survey of the sky, thanks to PRIMAger. If this survey is carried out successfully during the open observation time, planned for a period of one year (out of PRIMA's five-year lifetime), it will constitute an unprecedented database, providing essential information for the world astronomical community.