NASA's Nancy Grace Roman Space Telescope completed a key series of tests in September 2026, proving it can stay locked on targets with remarkable precision. From Sept. 15 to 21, engineers tested the observatory's fine-guidance system, and on Sept. 22 the Coronagraph Instrument received cosmic light for the first time.
The fine-guidance system uses small sections of the Wide Field Instrument's 18 detectors to monitor guide stars about four times per second, correcting any drift during exposures. The tests confirmed stability better than 1/100,000 of a degree for half an hour for Wide Field observations and for eight hours for Coronagraph observations. That level of control is roughly comparable to keeping a laser focused on a dime from 150 miles away, with engineers expecting further improvement.
The coronagraph's first look at space captured a faint star in the Large Magellanic Cloud, confirming the instrument can produce focused images. Detectors were intentionally kept warmer at first to prevent contamination, then cooled for a second observation that revealed many stars in a new location. Roman will also test a never-before-used spectral guiding mode, using wavelength patterns to position the telescope rather than a separate guider instrument.