NASA has selected PRIMA, a far-infrared space telescope, to advance into Phase B development. Scheduled for a 2033 launch and capped at $1.2 billion, the mission marks the debut of the agency’s new Probe Explorers class to investigate the origins of planets, stars, and cosmic water.
The space agency is officially moving forward with a specialized observatory designed to peer into wavelengths that have long frustrated astronomers. NASA announced that the PRobe far-Infrared Mission for Astrophysics, known as PRIMA, has cleared a major hurdle by advancing into preliminary design and technology development known as Phase B.
This telescope represents the inaugural project in a fresh category called Probe Explorers, tucked squarely inside the agency’s longstanding Explorers Program. Placed strategically between high-cost flagship observatories and smaller targeted missions, this tier mirrors the scale of planetary science’s New Frontiers program. When the category was created, each mission Explorer was set with a cost limit.
Hardware, Cryogenics, and Far-Infrared Reach
PRIMA will deploy a 1.8-meter primary mirror, sitting smaller than the 2.4-meter Hubble or Roman telescopes but eclipsing Europe’s Euclid. To capture faint far-infrared signals ranging from 25 to 260 microns, the observatory relies on extreme cooling. Passive thermal insulation, drawing from the architectural heritage of the Spitzer and Herschel space telescopes, pairs with a cryogenic refrigerator utilizing liquid helium-3. By employing helium-3 instead of helium-4, the system achieves lower temperatures of about 3.2 kelvin. Scientific instruments aboard include PRIMAger, a spectrophotometric camera and polarimeter operating across 25 to 235 microns with hiperespectral and polarimetric capabilities, and FIRESS, an enhanced survey spectrometer covering 24 to 235 microns. Both instruments use Kinetic Inductance Detectors chilled down to 0.1 kelvin, yielding a sensitivity order-of-magnitude greater than current infrared tech.
According to Nicky Fox, the PRIMA initiative serves as humanity’s upcoming portal to the distant cosmos, designed to shed light on hidden eras throughout cosmic history and improve our comprehension of how planets, stars, black holes, and Earth’s water originated.
Cost Caps, Timelines, and International Partnerships
Should PRIMA successfully pass its upcoming confirmation review—which evaluates technical, programmatic, and cost performance to decide if it is ready to transition into Phase C implementation—its total project expenses are limited to $1.2 billion, excluding launch expenses and other outside costs. That figure sits well below the price tags attached to other major observatories. Management of the mission rests with the Jet Propulsion Laboratory in southern California, supported by the Goddard Space Flight Center in Maryland and the Marshall Space Flight Center in Alabama.
Bridging the Gap in Cosmic Observation
By probing radiant energy that only emerges in the far-infrared, PRIMA will address a wide range of questions about the universe, filling a structural gap between existing infrared observatories, such as NASA’s James Webb Space Telescope, and radio telescopes. Agency leadership emphasizes that the mission ties neatly into a broader cadence of deployments.
Targeted to launch in 2033, for a planned five-year mission, PRIMA will conduct deep, sensitive surveys of the universe in far-infrared light to clarify how planetary systems form outside our solar system, how galaxies and black holes evolve, and how heavy elements and dust accumulate across cosmic history.