Key Portion of NASA’s Roman Space Telescope Clears Thermal Vacuum Test

[NASA]

One half of NASA’s nearly complete Nancy Grace Roman Space Telescope just passed a lengthy test to ensure it will function properly in the space environment. This milestone keeps Roman well on track for its target launch by May 2027, with the team aiming for as early as fall 2026.

This photo shows half of the NASA’s Nancy Grace Roman observatory — the outer barrel assembly, deployable aperture cover, and test solar arrays — fully deployed in a thermal chamber at NASA’s Goddard Space Flight Center in Greenbelt, Md., for environmental testing.

Credit: NASA/Sydney Rohde

“This milestone tees us up to attach the flight solar array sun shield to the outer barrel assembly, and deployable aperture cover, which we’ll begin this month,” said Jack Marshall, who leads integration and testing for these elements at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Then we’ll complete remaining environmental tests for the flight assembly before moving on to connect Roman’s two major assemblies and run the full observatory through testing, and then we’ll be ready to launch!”

Prior to this thermal testing, technicians integrated Roman’s deployable aperture cover, a visor-like sunshade, to the outer barrel assembly, which will house the telescope and instruments, in January, then added test solar panels in March. They moved this whole structure into the Space Environment Simulator test chamber at NASA Goddard in April.

There, it was subjected to the hot and cold temperatures it will experience in space. Next, technicians will join Roman’s flight solar panels to the outer barrel assembly and sunshade. Then the structure will undergo a suite of assessments, including a shake test to ensure it can withstand the vibrations experienced during launch.

This photo captures the installation of the test solar panels for NASA’s Nancy Grace Roman Space Telescope, which took place in March. One panel is lifted in the center of the frame on its way to being attached to the outer barrel assembly at right. The deployable aperture cover is stowed on the front of the outer barrel assembly, and the other half of the observatory — the spacecraft and integrated payload assembly, which consists of the telescope, instrument carrier, and two instruments — appears at the left of the photo.

Credit: NASA/Jolearra Tshiteya

Meanwhile, Roman’s other major portion — the spacecraft and integrated payload assembly, which consists of the telescope, instrument carrier, and two instruments — will undergo its own shake test, along with additional assessments. Technicians will install the lower instrument sun shade and put this half of the observatory through a thermal vacuum test in the Space Environment Simulator.

“The test verifies the instruments will remain at stable operating temperatures even while the Sun bakes one side of the observatory and the other is exposed to freezing conditions — all in a vacuum, where heat doesn’t flow as readily as it does through air,” said Jeremy Perkins, an astrophysicist serving as Roman’s observatory integration and test scientist at NASA Goddard. Keeping the instrument temperatures stable ensures their readings will be precise and reliable.

Technicians are on track to connect Roman’s two major parts in November, resulting in a complete observatory by the end of the year. Following final tests, Roman is expected to ship to the launch site at NASA’s Kennedy Space Center in Florida for launch preparations in summer 2026. Roman remains on schedule for launch by May 2027, with the team aiming for launch as early as fall 2026.

This infographic shows the two major subsystems that make up NASA’s Nancy Grace Roman Space Telescope. The subsystems are each undergoing testing prior to being joined together this fall.

Credit: NASA’s Goddard Space Flight Center

To virtually tour an interactive version of the telescope, visit:

https://roman.gsfc.nasa.gov/interactive

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.

By Ashley Balzer
NASA’s Goddard Space Flight Center, Greenbelt, Md.

​​Media Contact:
Claire Andreoli
NASA’s Goddard Space Flight Center
301-286-1940

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Last Updated

May 07, 2025

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Ashley Balzer

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Ashley Balzer

ashley.m.balzer@nasa.gov

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NASA Goddard Space Flight Center

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• Nancy Grace Roman Space Telescope
• Goddard Space Flight Center
• Technology

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