--- title: "NASA’s recipe for a cheaper billion-dollar telescope" description: "The PRIMA mission will fly in 2033 with a spare cryocooler left over from the Webb telescope" author: "Albion Grey" published: 2026-09-25T14:07:46Z modified: 2026-09-26T17:17:29Z url: https://rews.cc/a/nasa-s-recipe-for-a-cheaper-billion-dollar-telescope-391d87 language: en tags: ["nasa", "webb", "space", "telescope", "astrophysics", "science"] publisher: "Rews (https://rews.cc)" --- # NASA’s recipe for a cheaper billion-dollar telescope *The PRIMA mission will fly in 2033 with a spare cryocooler left over from the Webb telescope* By Albion Grey · September 25, 2026 · https://rews.cc/a/nasa-s-recipe-for-a-cheaper-billion-dollar-telescope-391d87 ## In brief - NASA approved development of PRIMA, a far-infrared space telescope capped at $1.2 billion excluding launch costs - PRIMA is targeted for launch in 2033, seven years away—far faster than typical flagship missions - It will reuse a spare Webb cryocooler, modified for helium-3, cooling its optics to 4.5 Kelvin - Rival X-ray mission AXIS was disqualified over schedule and budget concerns; PRIMA will be led by JPL - Early estimates put NASA’s next flagship, the Habitable Worlds Observatory, at around $11 billion, for launch in the 2040s NASA’s space telescopes come in two sizes: modest “Explorer-class” missions capped at a few hundred million dollars, and multibillion-dollar flagships such as the Nancy Grace Roman Space Telescope, launched last month at a cost of some $4.3 billion. This week the agency opened a middle aisle. It announced it will press ahead with PRIMA—the Probe far-Infrared Mission for Astrophysics—the first of a new class of “Probe Explorer” observatories meant to do more science for less money. The middle way has been a while coming. NASA has studied Probe Explorer concepts for years, after an independent panel of scientists recommended the category, but until recently it was unclear whether the agency’s science budget, under pressure from the Trump administration, could stretch to actually building one. PRIMA reached the pad, so to speak, by elimination: it was the sole finalist after NASA disqualified its rival, an X-ray observatory called AXIS, concluding that the concept study showed it would not meet schedule and budget constraints. The scientist who led the AXIS study blamed disruptions and mismanagement at NASA’s Goddard Space Flight Center in Maryland. PRIMA will instead be run by the Jet Propulsion Laboratory in Pasadena—itself in institutional crisis, with few missions in development and a series of layoffs. The prize on offer is speed. Flagship missions typically take decades to design, build and test; Roman was the exception, taking ten years from approval to launch. NASA wants PRIMA, capped at $1.2 billion excluding launch costs, on the launch pad seven years from now, in 2033. ## Second-hand helium The thrift is partly literal. PRIMA will observe the universe in faint far-infrared light, at wavelengths between 24 and 235 micrometers, which demands that its primary optics be chilled to 4.5 Kelvin—minus 451° Fahrenheit. That would normally mean building an elaborate new cryocooler. Instead PRIMA will use a spare left over from the development of the James Webb Space Telescope, modified to run on helium-3 rather than helium-4. Its kinetic inductance detectors will be colder still, at 100 milliKelvin, putting the observatory’s optics in contention for the coldest ever sent into space. The telescope, with a primary mirror 1.8 metres (5.9 feet) across, will park itself at the Sun-Earth L2 Lagrange point, a million miles from Earth, and weigh less than 3.4 metric tons (7,500 pounds) at launch. Its far-infrared eyes should see deeper into those bands than any past or present NASA observatory, including Spitzer and Webb, and will build on the legacy of Europe’s Herschel telescope, which illuminated the formation of cosmic filaments and the role of water in the birth of stars and planets. The scientists leading the mission list its targets as the origins of planets and their atmospheres, the coevolution of galaxies and black holes, and the changing properties of dust and metals over cosmic time. “The PRIMA mission is humanity’s next window into the deep Universe,” said Nicky Fox, associate administrator for NASA’s Science Mission Directorate, in a statement. “It will unveil the obscure across cosmic time to better understand the formation of planets, stars, black holes, and even how water on Earth came to be.” Shawn Domagal-Goldman, director of NASA’s Astrophysics Division, cast the mission as part of a deliberate rhythm: with Webb and Roman, the agency set “a cadence of launching premier-class missions in both halves of the decade”, and PRIMA will kick off the next one. The announcement moves the mission into Phase B of development, towards a preliminary design review and, a few years on, a confirmation review at headquarters that will give final approval to start assembling flight hardware. ## Flagships are still hard Looming behind PRIMA is the Habitable Worlds Observatory, the next flagship, pencilled in for the 2040s. It is expected to be at least as large as Webb—perhaps bigger, if super-heavy-lift rockets such as SpaceX’s Starship are available—and to observe in wavelengths from ultraviolet through visible to near-infrared. Early cost estimates come in at around $11 billion, on a par with Webb, which famously blew far past its original projection. “This is a sufficiently ambitious observatory where it’s going to require an all-of-nation \[approach\],” Mr Domagal-Goldman told a meeting of the National Academies’ Committee on Astronomy and Astrophysics. “Frankly, we’re going to need our partners internationally to be a big part of this as well.” His argument is that Roman has changed the odds. “We have proven with the launch of Nancy Grace Roman, ahead of schedule and on budget, that it is not a law of nature that these projects will go over schedule and over budget,” he said—while conceding, “that doesn’t mean they’re easy.” The lessons, as he tells them: define the architecture and requirements, understand the underlying technologies, and only then start cutting metal. “To put it succinctly, you need to understand the challenge, have a mission where the challenge is incredibly well understood, and then once you understand it, then you put your pedal to the metal and take that observatory to the launch pad as quickly as you can.” That is, in essence, the wager behind the whole Probe Explorer idea: that the discipline which kept Roman honest can be industrialised at the billion-dollar mark. PRIMA is a faute de mieux winner, chosen after its only rival stumbled, at an agency whose science budget is under strain and whose chosen centre is shedding staff. Its schedule is unprecedentedly tight for an observatory of this ambition, and history—Webb’s above all—warns that infrared telescopes with exotic cooling systems have a talent for overrunning. If NASA pulls it off, the middle aisle may become the busiest one. If not, it will merely have reinvented the cost overrun in a smaller size.