NASA’s next big eye on the cosmos is now fully assembled. On Nov. 25, technicians joined the inner and outer portions of the Nancy Grace Roman Space Telescope in the largest clean room at the agency’s Goddard Space Flight Center in Greenbelt, Maryland.
“Completing the Roman observatory brings us to a defining moment for the agency,” said NASA Associate Administrator Amit Kshatriya. “Transformative science depends on disciplined engineering, and this team has delivered — piece by piece, test by test — an observatory that will expand our understanding of the universe. As Roman moves into its final stage of testing following integration, we are focused on executing with precision and preparing for a successful launch on behalf of the global scientific community.”
NASA’s Nancy Grace Roman Space Telescope will survey vast swaths of the sky during its five-year primary mission, observing stars, galaxies, black holes, and exoplanets. This infographic previews some of the discoveries scientists anticipate from Roman’s data deluge. Download this infographic here.
After final testing, Roman will move to the launch site at NASA’s Kennedy Space Center in Florida for launch preparations in summer 2026. Roman is slated to launch by May 2027, but the team is on track for launch as early as fall 2026. A SpaceX Falcon Heavy rocket will send the observatory to its final destination a million miles from Earth.
“With Roman’s construction complete, we are poised at the brink of unfathomable scientific discovery,” said Julie McEnery, Roman’s senior project scientist at NASA Goddard. “In the mission’s first five years, it’s expected to unveil more than 100,000 distant worlds, hundreds of millions of stars, and billions of galaxies. We stand to learn a tremendous amount of new information about the universe very rapidly after Roman launches.”
On Nov. 25, technicians meticulously connected the inner and outer segments of NASA’s Roman Space Telescope, as shown in this time-lapse. The observatory will undergo final testing and then move to NASA’s Kennedy Space Center in Florida for launch preparations in summer 2026.
Observing from space will make Roman very sensitive to infrared light — light with a longer wavelength than our eyes can see — from far across the cosmos. Pairing its crisp infrared vision with a sweeping view of space will allow astronomers to explore myriad cosmic topics, from dark matter and dark energy to distant worlds and solitary black holes, and conduct research that would take hundreds of years using other telescopes.
“Within our lifetimes, a great mystery has arisen about the cosmos: why the expansion of the universe seems to be accelerating. There is something fundamental about space and time we don’t yet understand, and Roman was built to discover what it is,” said Nicky Fox, associate administrator, Science Mission Directorate, NASA Headquarters in Washington. “With Roman now standing as a complete observatory, which keeps the mission on track for a potentially early launch, we are a major step closer to understanding the universe as never before. I couldn’t be prouder of the teams that have gotten us to this point.”
Double vision
Roman is equipped with two instruments: the Wide Field Instrument and the Coronagraph Instrument technology demonstration.
NASA’s Roman Space Telescope will bring scientists closer to understanding the mysteries of dark energy and dark matter, and will help establish how common planets like Earth are throughout our galaxy. Roman is on track for launch by May 2027, with teams working toward a launch as early as fall 2026.
The coronagraph will demonstrate new technologies for directly imaging planets around other stars. It will block the glare from distant stars and make it easier for scientists to see the faint light from planets in orbit around them. The coronagraph aims to photograph worlds and dusty disks around nearby stars in visible light to help us see giant worlds that are older, colder, and in closer orbits than the hot, young super-Jupiters direct imaging has mainly revealed so far.
“The question of ‘Are we alone?’ is a big one, and it’s an equally big task to build tools that can help us answer it,” said Feng Zhao, the Roman Coronagraph Instrument manager at NASA’s Jet Propulsion Laboratory in Southern California. “The Roman Coronagraph is going to bring us one step closer to that goal. It’s incredible that we have the opportunity to test this hardware in space on such a powerful observatory as Roman.”
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The coronagraph team will conduct a series of pre-planned observations for three months spread across the mission’s first year and a half of operations, after which the mission may conduct additional observations based on scientific-community input.
The Wide Field Instrument is a 288-megapixel camera that will unveil the cosmos all the way from our solar system to near the edge of the observable universe. Using this instrument, each Roman image will capture a patch of the sky bigger than the apparent size of a full Moon. The mission will gather data hundreds of times faster than NASA’s Hubble Space Telescope, adding up to 20,000 terabytes (20 petabytes) over the course of its five-year primary mission.
“The sheer volume of the data Roman will return is mind-boggling and key to a host of exciting investigations,” said Dominic Benford, Roman’s program scientist at NASA Headquarters.
Survey trifecta
Using the Wide Field Instrument, Roman will conduct three core surveys that will account for 75% of the primary mission. The High-Latitude Wide-Area Survey will combine the powers of imaging and spectroscopy to unveil more than a billion galaxies strewn across a wide swath of space and time. Astronomers will trace the evolution of the universe to probe dark matter — invisible matter detectable only by how its gravity affects things we can see — and trace the formation of galaxies and galaxy clusters over time.
The High-Latitude Time-Domain Survey will probe our dynamic universe by observing the same region of the cosmos repeatedly. Stitching these observations together to create movies will allow scientists to study how celestial objects and phenomena change over time periods of days to years. That will help astronomers study dark energy — the mysterious cosmic pressure thought to accelerate the universe’s expansion — and could even uncover entirely new phenomena that we don’t yet know to look for.
Roman’s Galactic Bulge Time-Domain Survey will look inward to provide one of the deepest views ever of the heart of our Milky Way galaxy. Astronomers will watch hundreds of millions of stars in search of microlensing signals — gravitational boosts of a background star’s light caused by the gravity of an intervening object. While astronomers have mainly discovered star-hugging worlds, Roman’s microlensing observations can find planets in the habitable zone of their star and farther out, including worlds like every planet in our solar system except Mercury. Microlensing will also reveal rogue planets — worlds that roam the galaxy untethered to a star — and isolated black holes. The same dataset will reveal 100,000 worlds that transit, or pass in front of, their host stars.
The remaining 25% of Roman’s five-year primary mission will be dedicated to other observations that will be determined with input from the broader scientific community. The first such program, called the Galactic Plane Survey, has already been selected.
Because Roman’s observations will enable such a wide range of science, the mission will have a General Investigator Program designed to support astronomers to reveal scientific discoveries using Roman data. As part of NASA’s commitment to Gold Standard Science, NASA will make all of Roman’s data publicly available with no exclusive use period. This ensures multiple scientists and teams can use data at the same time, which is important since every Roman observation will address a wealth of science cases.
Roman’s namesake — Dr. Nancy Grace Roman, NASA’s first chief astronomer — made it her personal mission to make cosmic vistas readily accessible to all by paving the way for telescopes based in space.
“The mission will acquire enormous quantities of astronomical imagery that will permit scientists to make groundbreaking discoveries for decades to come, honoring Dr. Roman’s legacy in promoting scientific tools for the broader community,” said Jackie Townsend, Roman’s deputy project manager at NASA Goddard. “I like to think Dr. Roman would be extremely proud of her namesake telescope and thrilled to see what mysteries it will uncover in the coming years.”
The Nancy Grace Roman Space Telescope is managed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, with participation by NASA’s Jet Propulsion Laboratory in Southern California; Caltech/IPAC in Pasadena, California; the Space Telescope Science Institute in Baltimore; and a science team comprising scientists from various research institutions. The primary industrial partners are BAE Systems Inc. in Boulder, Colorado; L3Harris Technologies in Rochester, New York; and Teledyne Scientific & Imaging in Thousand Oaks, California.
To learn about the Roman Space Telescope, visit: