NASA's Roman Space Telescope launches on mission to map dark energy and hunt planets by the thousands

NASA's Nancy Grace Roman Space Telescope lifted off before dawn on Sunday, beginning a five-year mission that scientists say could reshape understanding of dark energy, dark matter and the population of planets beyond the solar system. The observatory launched at 7:26 a.m. EDT aboard a SpaceX Falcon Heavy rocket from Launch Complex 39A at Kennedy Space Center in Florida, on a three-month journey toward a stable orbital position nearly a million miles from Earth.

Roman is NASA's newest flagship observatory, joining Hubble and the James Webb Space Telescope in a line of large space-based instruments built to answer fundamental questions about the universe. Unlike its predecessors, which excel at studying individual objects in fine detail, Roman is designed for speed and breadth: a wide-field camera intended to survey enormous swaths of sky and catalog objects by the billions rather than the dozens.

The numbers behind the mission

Roman carries a 2.4-meter primary mirror, the same size as Hubble's, paired with a 300.8-megapixel Wide Field Instrument that NASA says can capture images as sharp as Hubble's but across a field of view roughly 100 times larger. According to the space agency, that combination should let Roman survey the sky more than a thousand times faster than Hubble can. Over its planned five years of operations, mission scientists expect the telescope to detect more than 100,000 exoplanets through a technique called gravitational microlensing, along with thousands of supernovae, billions of galaxies and tens of billions of stars. The spacecraft is expected to return roughly 1.4 terabytes of raw data per day, which NASA has said will be made publicly available on a rolling basis rather than held for exclusive use by individual research teams. The mission's official lifecycle cost, covering development and five years of science operations, stands at $4.3 billion.

How Roman came to be

Roman's origins trace back more than a decade. Its primary mirror began as a piece of hardware donated to NASA around 2012 by the National Reconnaissance Office, the intelligence agency responsible for U.S. spy satellites, which had built it to specifications similar to Hubble's optics but never flew it. NASA later built the telescope now known as Roman around that mirror, initially under the name WFIRST (Wide Field Infrared Survey Telescope). The mission was formally approved for development in 2020 and later renamed for Nancy Grace Roman, NASA's first chief astronomer, who helped establish the case for a space-based observatory decades before Hubble launched. The program survived several rounds of proposed cancellation in federal budget negotiations over the years that followed, with its lifecycle cost eventually rising from an initial 2020 estimate of about $3.9 billion to the current $4.3 billion figure as schedules and technical plans were adjusted.

The telescope's data will be used by two broad groups of researchers who rarely share an instrument this directly: cosmologists trying to pin down the nature of dark energy, the mysterious force accelerating the universe's expansion, and planetary scientists searching for and characterizing worlds around other stars. Roman will measure dark energy's effects by tracking how light from distant galaxies is bent by the gravity of matter between them and Earth, and by observing large numbers of a specific class of exploding stars, called Type Ia supernovae, that serve as reliable cosmic distance markers. On the exoplanet side, the telescope's coronagraph instrument — a technology demonstration rather than a core science instrument — is designed to block out starlight well enough to directly image planets orbiting nearby stars, something few current instruments can do for anything smaller or fainter than a large gas giant.

Because Roman's survey data will be released publicly and continuously through a cloud-based archive, researchers without direct affiliation to the mission, including scientists at universities and observatories with no formal role in Roman's construction, will have access to the same catalogs as the mission team, an arrangement NASA has said is intended to maximize the science produced from the observatory.

What officials and scientists are saying

At a post-launch briefing, Julie McEnery, Roman's senior project scientist, described the stakes for cosmology in stark terms.

"We're probably not going to confirm the standard model of how the universe works. We're very likely to demonstrate that our standard model is wrong, and to set ourselves on a path to figuring out how does our universe really work."

Nicky Fox, associate administrator for NASA's Science Mission Directorate, called the launch "a spectacular mission" and said the telescope's field of view would let it do things "we've never been able to do before," predicting it would eventually find "thousands of supernovae, tens of thousands of planets, billions of galaxies and tens of billions of stars." Jackie Townsend, Roman's project manager, told reporters after liftoff that the ride to orbit had been smooth, calling it "a glorious dawn launch." Vanessa Bailey, the coronagraph instrument scientist at NASA's Jet Propulsion Laboratory, said the team hopes the instrument will eventually be sensitive enough to directly image a Jupiter-like planet around a nearby star using reflected visible light, and then use that light to study the composition of the planet's atmosphere.

What happens next

Roman deployed its solar panels and sunshade about 83 minutes after launch, according to NASA's mission updates, and engineers expect to unfold its antenna and move a protective aperture cover into place over the coming days. The spacecraft will then spend roughly three months traveling to the Sun-Earth L2 Lagrange point, a gravitationally stable location about one million miles from Earth already used by Webb, where it will settle into a halo orbit shielded from the sun's heat and light by Earth's shadowed side.

During that transit and for a period afterward, ground teams will carry out what NASA calls commissioning: turning on, calibrating and testing each of Roman's systems and instruments before routine science observations begin. NASA has said the commissioning schedule remains subject to change as the team evaluates the spacecraft's performance, but the agency has set a general expectation of releasing Roman's first official science images in early 2027. Once operational, Roman's core work will include a high-latitude survey mapping the large-scale structure of the universe, a years-long microlensing survey pointed toward the crowded center of the Milky Way to catalog exoplanets, and a rolling search for distant supernovae — the beginning of what mission scientists describe as a systematic effort to catch, in Roman project scientist McEnery's words at a briefing carried by outlets including Fortune, "the weird, the rare and the unusual" among billions of cataloged objects.