In this photo, technicians install solar panels onto the outer portion of NASA's Nancy Grace Roman Space Telescope. Roman's inner portion is in the background just left of center. By the end of the year, technicians plan to connect the two halves and complete the Roman observatory. Credit: NASA/Sydney Rohde

On June 14 and 16, technicians installed solar panels onto NASA's Nancy Grace Roman Space Telescope, one of the final steps in assembling the observatory. Collectively called the Solar Array Sun Shield, these panels will power and shade the observatory, enabling all the mission's observations and helping keep the instruments cool.

The solar panels on NASA's Nancy Grace Roman Space Telescope are covered in a total of 3,902 solar cells that will convert sunlight directly into electricity much like plants convert sunlight to chemical energy. When tiny bits of light, called photons, strike the cells, some of their energy transfers to electrons within the material. This jolt excites the electrons, which start moving more or jump to higher energy levels. In a solar cell, excited electrons create electricity by breaking free and moving through a circuit, sort of like water flowing through a pipe. The panels are designed to channel that energy to power the observatory. Credit: NASA / Sydney Rohde

"At this point, the observatory is about 90% complete," said Jack Marshall, the Solar Array Sun Shield lead at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "We just need to join two large assemblies, and then we'll run the whole Roman observatory through a series of tests. We're currently on track for launch several months earlier than the promised date of no later than May 2027."

Now that the solar panels are installed on the outer portion of NASA's Nancy Grace Roman Space Telescope, technicians are readying the assembly for vibration testing to ensure it will withstand the extreme shaking experienced during launch. Credit: NASA / Sydney Rohde

The team is working toward launch as early as fall 2026.

Technicians have installed solar panels onto the outer portion of NASA's Nancy Grace Roman Space Telescope. By the end of the year, technicians plan to connect the two halves and complete the Roman observatory. Credit: NASA / Sydney Rohde

The Solar Array Sun Shield is made up of six panels, each covered in . The two central panels will remain fixed to the outer barrel assembly (the observatory's outer shell) while the other four will deploy once Roman is in space, swinging up to align with the center panels.

The panels will spend the entirety of the mission facing the sun to provide a steady supply of power to the observatory's electronics. This orientation will also shade much of the observatory and help keep the instruments cool, which is critical for an infrared observatory. Since is detectable as heat, excess warmth from the spacecraft's own components would saturate the detectors and effectively blind the telescope.

  • Technicians have installed solar panels onto the outer portion of NASA's Nancy Grace Roman Space Telescope. The inner portion appears in the background of this photo. By the end of the year, technicians plan to connect the two halves and complete the Roman observatory. Credit: NASA / Sydney Rohde

  • Technicians have installed solar panels onto the outer portion of NASA's Nancy Grace Roman Space Telescope. By the end of the year, technicians plan to connect the two halves and complete the Roman observatory. Credit: NASA / Sydney Rohde

"Now that the panels have been installed, the outer portion of the Roman observatory is complete," said Goddard's Aaron Vigil, a working on the array. Next, technicians will test-deploy the and the observatory's "visor" (the deployable aperture cover). The team is also testing the core portion of the observatory, assessing the electronics and conducting a thermal vacuum test to ensure the system operates as planned in the harsh space environment.

Technicians have installed solar panels onto the outer portion of NASA's Nancy Grace Roman Space Telescope. By the end of the year, technicians plan to connect the two halves and complete the Roman observatory. Credit: NASA / Sydney Rohde

This will keep the project on track to connect Roman's inner and outer segments in November, resulting in a whole by the end of the year that can then undergo pre-launch tests.

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

Provided by NASA's Goddard Space Flight Center