Engineers at the Goddard Space Flight Center have successfully completed the final inspection of the primary mirror for the Nancy Grace Roman Space Telescope. This critical milestone ensures that the 7.9-foot mirror, which serves as the heart of the observatory, is free of defects and perfectly aligned for its upcoming mission to capture high-resolution panoramas of the cosmos. The inspection, conducted in late May, confirmed that the mirror’s specialized silver coating remains pristine following rigorous pre-launch vibration testing.
The mirror is engineered for extreme precision, featuring a surface smoothness where average imperfections are measured at just 1.2 nanometers. Constructed from ultralow-expansion glass, the component is designed to maintain its shape despite the drastic temperature fluctuations encountered during the transition from Earth to the deep freeze of space. This stability is essential for the telescope to maintain the image quality required to study distant galaxies and exoplanets.
Beyond its structural integrity, the mirror’s unique silver coating was specifically selected to optimize the reflection of near-infrared light, distinguishing it from the gold-coated mirrors of the James Webb Space Telescope or the aluminum-based optics of the Hubble Space Telescope. With the final visual assessment complete, the team is now preparing to transport the observatory to the Kennedy Space Center in Florida.
The mission is currently on schedule for a launch in early September. Once operational, the Roman Space Telescope is expected to provide unprecedented insights into the universe, with the first cosmic images anticipated to arrive within months of deployment.
