Webb Space Telescope’s Deployable Tower Assembly Extends in Space

Webb Central Tower deploymemt. Credit: NASA’s Goddard Space Flight Center Conceptual Image Lab

Yesterday afternoon, the Webb team successfully extended the observatory’s Deployable Tower Assembly (DTA), creating critical distance between the two halves of the spacecraft.

The DTA extended about 48 inches (1.22 meters), putting room between the upper section of the observatory, which houses the mirrors and scientific instruments, and the spacecraft bus, which holds the electronics and propulsion systems. This creates enough distance to allow the sensitive mirrors and instruments to cool down to the necessary temperatures to detect infrared light. This gap will also provide room for the sunshield membranes to fully unfold.


Engineers perform the final deployment test of the James Webb Space Telescope’s Deployable Tower Assembly in June 2021 at Northrop Grumman Space Park in Redondo Beach, California. Credit: NASA’s Goddard Space Flight Center

The deployment took more than six and a half hours, as engineers activated release devices and configured heaters, software, and electronics, before commanding the DTA itself to extend. The movement of the DTA, which looks like a large, black pipe, is driven by a motor. The team began the deployment at approximately 9:45 a.m. EST and completed it at approximately 4:24 p.m. EST.

This step furthers the team’s progress in deploying Webb’s sunshield – a human-controlled, multi-day process that will continue with the release of aft momentum flap and the sunshield covers.