NASA is gearing up to launch its next flagship space telescope – combining spy technology with sophisticated infrared detectors

NASA plans to soon launch a new space telescope that will survey a billion galaxies to trace how the universe evolved over time, all courtesy of America's spy program and decades of research into detector technology.

The telescope, known as the Nancy Grace Roman Space Telescope, was first developed by the National Reconnaissance Office, before being transferred to NASA in 2012. The intelligence agency no longer needed the hardware for its future missions, so it sent the unused telescope to NASA. The space agency spent over a decade making modifications and aims to launch the telescope into space as early as Aug. 30, 2026.

Once in position, the telescope will take data that astronomers like me hope will help answer some of the field's most puzzling questions.

Roman's scientific goals

You can expect a slew of exciting discoveries from the new telescope because it was built to look across the universe and study the three-dimensional distribution of dark matter. While scientists haven't directly observed it before, dark matter produces unseen effects on objects in the universe, similar to those produced by visible matter.

Likewise, Roman will see exploding stars called supernovas that allow astronomers to measure how fast the universe has been expanding. Those measurements will help astronomers measure the varying expansion rate of the universe. Dark matter and dark energy, also not yet directly observed, together are the source of the vast majority of energy in the universe, but their physical natures are unknown.

Closer to home, Roman will monitor small variations in light from stars near the center of the Milky Way galaxy in order to infer the presence of rogue planets drifting between the stars. As a planet passes in front of a star, it briefly perturbs and magnifies the light from the star behind it, confirming its presence.

Finally, Roman has a coronagraph instrument that will test the technology for future missions that plan to detect Earth-like planets around other stars. A coronagraph blocks most of the light from a star so astronomers can detect the much fainter planets orbiting it. For an Earth-like planet around a Sun-like star, the host star can be 10 billion times brighter than the planet.

The Roman telescope's coronagraph will help it study distant planets as they pass in front of a star.

From spy telescope to surveying the universe

When NASA received Roman, it turned one challenge about the telescope's spy design into an opportunity. The telescope has a wide field of view, at least compared with most space telescopes made for astronomy. This means it can see a large swath of the sky at once. There lies an opportunity – while telescopes like the Hubble Space Telescope see narrow fields very deeply, Roman will be able to see much larger fields.

Roman's camera has such a wide field because its spy telescope origins give it unusually fast optics. This means that it has a relatively short focal length – the distance between the mirror and the point where the light focuses – for the diameter of its mirror. Effectively, it can project a much larger piece of sky onto a fixed area in the telescope, called the focal plane. Its mirror is about the same diameter as Hubble's, yet it can capture an area about a hundred times larger per image.

Big science, big detectors

One modification that NASA made included building a large focal plane, the component of the telescope that collects light, made up of 18 wide area near-infrared detectors. These detectors are almost identical to those in the James Webb Space Telescope, but they have four times the number of pixels. They will take in infrared light, which has longer wavelengths than the light that human eyes can see. But while each one on Webb has 4 megapixels, or 4 million pixels, Roman's detectors have about 16 megapixels, bringing the full coverage of the 18 detectors to around 300 megapixels.

These detectors are modern marvels in their own right and represent the culmination of a long heritage of new technology that enables new discoveries.

I worked with colleagues in the early 2000s to advance the technology used in this type of detector – versions of which have been used on Hubble and Webb. We measured in the lab how the detectors performed in a simulated space environment. We needed to make sure that they could still sense even tiny signals out in space, which would allow the telescope to take in light from very faint planets, stars and galaxies.

We now see the fruits of those efforts in the beautiful images that Webb has produced, including of perplexing young galaxies in the early universe. I'm excited to see the images Roman will produce, using the newest iteration of this technology.

New technology and a legacy of discovery

Astronomers are already eagerly awaiting the astronomical discoveries that Roman and its ultra-sensitive infrared detectors will produce. But how can we have such high expectations of a space observatory that has not even left the ground?

It is because technology precedes discovery. Roman's detectors are the latest iteration in a long history of scientific success. You can directly tie countless Nobel Prizes to the telescope.

The team of physicists that inferred the existence of dark energy received a Nobel Prize in 2011. The observations they used came from new families of sensitive digital imaging detectors called charge-coupled devices, or CCDs, invented in the early 1970s. These devices helped astronomers measure how fast stars moved through space, which supported the notion that space is permeated with some unknown "dark" matter.

Important validation of that Nobel-Prize-winning research came from near-infrared detectors that used the same technology as Roman.

Likewise, the Nobel Prize for the discovery of the supermassive black hole in the center of the Milky Way galaxy was awarded to researchers who used a variety of infrared instruments on large ground-based telescopes.

All these telescopes had been outfitted with newly available infrared detectors. In fact, this Nobel Prize highlights the impact of three technologies: infrared detectors, big telescopes and adaptive optics.

Part of a continuing cycle

People often think of scientific discovery as a eureka light bulb above the head of a brilliant scientist, but discovery rarely happens that way. More often, someone uses a new technology to look at something that, until that point, remained unseen.

Galileo used a telescope to observe the previously unseen moons of Jupiter. Then, the next technological iteration replaced the human eye with photographic plates in the 19th century, which led to the first sensitive all-sky surveys. These surveys yielded a plethora of astronomical discoveries, including that the universe is expanding.

The 1970s saw electronic detectors take over for photographic plates, increasing the detector sensitivity by an order of magnitude. These gains were then transferred to infrared, rather than just visible light, opening a new window into the universe and another wave of discovery.

And now, it is Roman's turn. But Roman won't be on the cutting edge for long, because NASA is already designing the next space telescope.

The agency is developing the Habitable Worlds Observatory, a future space mission with the goal of directly imaging Earth-like planets around nearby stars and identifying signs of life in the universe.

Let's hope for a smooth ride to space for Roman. In the meantime, scientists are already planning for the next generation of discoveries, one new detector at a time.

This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world. It was written by: Don Figer, Rochester Institute of Technology

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Don Figer receives funding from NASA, NSF.