NASA is advancing the development of PRIMA, a proposed far-infrared space telescope that could give astronomers a new view of how planets, stars, galaxies and black holes form and evolve. The agency announced on September 23, 2026, that the mission had reached Phase B, a stage focused on developing and refining the observatory’s technical and program plans.
PRIMA stands for Probe far-Infrared Mission for Astrophysics. If it passes the next technical, programmatic and financial reviews, the project could become the first mission in NASA’s new Probe Explorers class of astrophysics observatories. The agency expects the mission to launch in 2033 and has planned a five-year science mission.
According to the NASA announcement, the project could be limited to a development cost of $1.2 billion. That figure does not include the launch or other expenses outside the project’s development budget, making the upcoming evaluations important to the mission’s future.
Why far-infrared astronomy matters
Far-infrared light occupies a part of the electromagnetic spectrum that is especially useful for examining cold dust and gas in space. These materials can hide regions where stars and planets are forming from telescopes that observe mainly in visible or shorter infrared wavelengths.
By studying this radiation, PRIMA is expected to help scientists investigate the environments where planets emerge outside the Solar System. The observatory could also provide information about the evolution of galaxies and black holes, as well as the distribution of dust and heavier elements throughout cosmic history.
Those observations would complement, rather than replace, the work of other major space observatories. NASA’s James Webb Space Telescope has expanded the study of the infrared universe, while the Nancy Grace Roman Space Telescope is designed to survey large areas of the sky. PRIMA would target a different range of infrared wavelengths, helping fill an observational gap between infrared observatories and radio telescopes.
What PRIMA could investigate
One of the mission’s central scientific goals is to improve understanding of how planetary systems are assembled. The process begins in clouds of gas and dust, where young stars and the material that may form planets are embedded. Far-infrared observations can reveal properties of that material and offer clues about the conditions surrounding planets beyond our Solar System.
The mission would also examine the relationship between galaxies and the black holes at their centers. Over billions of years, galaxies have changed through star formation, interactions and the buildup of heavy elements. By detecting infrared emissions associated with dust and other materials, PRIMA could help researchers trace some of those changes across the history of the universe.
Because dust can absorb visible light and re-emit energy in infrared wavelengths, far-infrared astronomy provides a way to study cosmic regions that are difficult to observe directly. This capability is particularly relevant to the early stages of star formation and to the activity surrounding black holes.
A new class of NASA astrophysics missions
PRIMA is being developed as the first project in NASA’s Probe Explorers class. The mission concept is built around a space telescope of approximately 5.9 feet, according to the agency’s project information. Its relatively focused design is intended to support major astrophysics investigations while remaining within a defined development cost limit.
Several NASA centers are involved in the project’s development. The Jet Propulsion Laboratory in California, the Goddard Space Flight Center in Maryland and the Marshall Space Flight Center in Alabama are among the facilities connected to the mission. Their roles reflect the technical and scientific coordination required to design an observatory capable of operating at far-infrared wavelengths.
Reaching Phase B does not mean that launch is guaranteed. The project must continue through technical, programmatic and financial assessments before NASA can confirm its next steps. The agency’s current planning points to a 2033 launch and a five-year mission, but those milestones depend on the results of the remaining evaluations.
How PRIMA would complement Webb and Roman
The James Webb Space Telescope has become a powerful tool for observing infrared light, including distant galaxies, forming stars and planetary systems. Roman will add a wide-field view designed to examine large populations of galaxies and stars. PRIMA would approach the universe from another direction by focusing on far-infrared wavelengths that are well suited to cold dust and gas.
Together, these observatories could provide a broader picture of cosmic evolution. Webb and Roman can identify and characterize objects across important infrared ranges, while PRIMA could investigate the obscured material involved in star and planet formation. The combination would help astronomers connect the birth of planetary systems with the larger history of galaxies and black holes.
For now, PRIMA remains a mission under development. Its progress into Phase B marks a significant step, but the telescope’s final approval, cost and launch schedule will depend on NASA’s future reviews. If confirmed, the observatory would add a new capability to the United States’ space science program and expand the study of the cold, dust-rich universe.
