Building Roman – NASA Science

January 29, 2026

Technicians have completed construction of NASA’s Nancy Grace Roman Space Telescope.

The Roman Observatory is expected to launch no later than May 2027, with the team aiming for a launch as early as fall 2026. The mission will revolutionize our understanding of the universe with its deep, sharp, panoramic views of space.

More than a thousand technicians and engineers assembled Roman from millions of individual components. Many parts were built and tested simultaneously to save time. Now that the observatory is assembled, it will undergo a series of tests before being shipped to NASA’s Kennedy Space Center in Florida in the summer of 2026.

The entire optical telescope is the heart of the Roman observatory. It consists of a main mirror, designed and built at L3Harris Technologies in Rochester, New York, as well as nine additional mirrors, support structures and electronics.

The Roman team got off to a good start by receiving the telescope certificate primary mirrorwhich will collect and concentrate light from cosmic objects near and far, from another government agency, then modify it to meet NASA’s needs. Using this mirror, Roman will capture stunning space views with a field of view at least 100 times larger than Hubble’s.

Roman will peer into dust and vast expanses of space and time to study the universe using infrared light, which human eyes cannot see. The amount of detail these observations will reveal is directly related to the size of the telescope’s mirror, since a larger surface area collects more light and measures finer details. Roman’s main mirror measures 2.4 meters in diameter, the same size as the main mirror of the Hubble Space Telescope, but less than a quarter of its weight (410 pounds or 186 kilograms) thanks to major technological improvements.

Josh Abel

Senior Optical Telescope Assembly Systems Engineer at NASA Goddard

The main mirror, in concert with other optics, will send light to Roman’s two scientific instruments: the Wide field instrument And Coronagraph instrument. When light enters Roman’s 8-foot aperture, it is reflected and focused by the curved primary mirror, then reflected and focused again by the secondary mirror. Then, light from different parts of the sky spreads to each instrument, so Roman can use both at once.

The telescope was delivered on November 7, 2024 to the largest clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Meanwhile, technicians from Goddard and Teledyne Scientific & Imaging were developing the detector network. This device will convert starlight into electrical signals, which will then be decoded into 288-megapixel images of large areas of the sky. The combination of Roman’s fine resolution and huge images has never been possible on a space telescope before.

Greg Mosby

research astrophysicist at NASA Goddard

The detectors, each the size of a cracker, each have 16 million tiny pixels, providing the mission with exquisite image resolution. Eighteen have been integrated into the focal plane of Roman’s camera, and six more are reserved as flight-qualified spares.

Once completed and tested, the detector array was inserted into the mission’s main instrument: a sophisticated camera called Wide field instrumentwhich was assembled and tested at Goddard and BAE Systems, Inc.

The Wide Field Instrument, or WFI, is an infrared camera that will give Roman the same angular resolution as Hubble but with a field of view at least 100 times larger. Its extensive cosmic studies will help scientists discover detailed and unique new information about planets beyond our solar system, unravel mysteries like dark energy, and map how matter is structured and distributed in the cosmos. The mission’s broad and precise vision will provide an extraordinary resource for a wide range of additional investigations.

Using this instrument, each Roman image will capture a portion of the sky larger than the apparent size of a full moon. The mission will collect data hundreds of times faster than Hubble, totaling up to 20,000 terabytes (20 petabytes) over the course of its five-year primary mission.

Technicians from BAE and Goddard assembled the WFI in a clean room in Boulder, Colorado. The team then performed comprehensive environmental testing in space-like conditions and delivered the WFI to Goddard in the summer of 2024. It was linked to other observatory systems the following winter.

Technicians from NASA’s Jet Propulsion Laboratory built the Coronagraph instrument. The Coronagraph will showcase new technologies for directly imaging planets around other stars. This will block the glare from distant stars and make it easier for scientists to see the faint light from planets orbiting them. The Coronagraph aims to image dusty worlds and disks around nearby stars in visible light to help us see giant worlds that are older, colder, and in closer orbits than direct imaging of hot young super-Jupiters has mostly revealed so far.

The coronagraph team will conduct a series of pre-planned observations over three months spread over the mission’s first year and a half of operations, after which the mission may conduct additional observations based on feedback from the scientific community.

After JPL testing, the Coronagraph was delivered to Goddard in May 2024. It was integrated into Roman’s instrument carrier, a piece of infrastructure that will hold the mission’s instruments, in October 2024. Then, the instrument carrier was attached to the spacecraft in December 2024.

By 2025, all of Roman’s components were complete and undergoing testing as subsystems. Technicians installed test versions of the Solar panel solar shield signs on the Assembling the outer barrel – part of the observatory that will protect and shade the primary mirror – inside Goddard’s largest clean room in preparation for testing.

The team covered Roman’s telescope section in a protective tent and pushed it out of the clean room using pressurized air to make it float like a hovercraft. Then they lifted it onto a shaking table for vibration testing to simulate launch stresses. Next, technicians moved the components into the Space Environment Simulator chamber for a month of testing at low pressure and different temperatures, mimicking space conditions.

that of Roman Solar panel solar shield is made up of six panels, each covered with solar cells. The two central panels will remain attached to the Assembling the outer barrel while the other four will deploy once Roman is in space, swinging to align with the center panels.

The panels will spend the entire mission facing the Sun to provide a constant power supply to the observatory’s electronics. This orientation will also shade much of the observatory and help keep the instruments cool, which is essential for an infrared observatory. Since infrared light is detectable as heat, excessive heat from spacecraft components would saturate the detectors and effectively blind the telescope.

Technicians installed Roman’s solar panels in June 2025, followed by Lower instrument sunshade — a smaller set of panels that will play a vital role in keeping Roman’s instruments cool and stable. The technicians trained to deploy the solar panels and Deployable opening cover — a sun visor in the form of a visor.

By fall 2025, the observatory was divided into two main segments. The inner part included the telescope, instrument rack, two instruments and the spacecraft bus, while the outer part included the outer gun assembly, deployable aperture cover and solar panels. The exterior part has successfully passed a shake test and an intense sound explosion, while the interior part has undergone a 65-day thermal vacuum test.

On November 25, 2025, technicians brought the two segments together and the observatory was complete.

Now Roman will undergo testing as a full-fledged observatory. Roman will move to the launch site at NASA’s Kennedy Space Center in Florida for launch preparations in summer 2026. Roman is scheduled to launch by May 2027, but the team is on track for a launch as early as fall 2026. Follow the journey to launch at nasa.gov/roman.

Discover other photos of the Roman observatory:

Ashley is the Senior Science Editor for NASA’s Nancy Grace Roman Space Telescope.