NASA completes alignment of Webb’s primary mirror

Edinburgh, 22 March 2022. – The critical mirror alignment steps of NASA’s James Webb Space Telescope (JWST) are now complete and the team expects to meet or even exceed the optical performance science goals set for the space telescope, NASA said.

Every optical parameter that has been checked and tested is performing at, or above, expectations, according to NASA. The team found no critical issues and no measurable contamination or blockages to the observatory’s optical path either.

Webb is the first telescope in space to use a segmented primary mirror. The 6.5-meter mirror is made up of 18 hexagonal, beryllium mirror segments that had to be folded up for launch. The segments were then unfolded in space and each mirror was adjusted to within nanometers to form a unified mirror surface. As the fine phasing of alignment is complete, Webb’s primary imager, the Near-Infrared Camera, is fully aligned to the mirrors.

The team will carry out further alignment steps in the next six weeks before the final science instrument preparations can begin. The Near-Infrared Spectrograph, Mid-Infrared Instrument, Near InfraRed Imager and Slitless Spectrograph will also have to be aligned. The science instrument preparations will take about two months after which the first full-resolution imagery and science data will be released.