James Webb Space Telescope’s tower assembly is extended to allow for the deployment of sunshield

The massive sunshield for the James Webb Space Telescope is one step closer to being completed.

The massive new space observatory’s deployable tower assembly (DTA), a 48-inch-long (1.2-meter) shaft that joins the telescope’s two sections, was successfully extended on Wednesday (Dec. 29), NASA officials announced in a statement.

The DTA on the James Webb Space Telescope provides needed space between the telescope’s massive mirror and scientific instruments and the spacecraft bus, which houses the telescope’s 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,” NASA stated in a statement. “This gap will also provide room for the sunshield membranes to fully unfold.”

At 9:45 a.m. EST (1445 GMT) on Wednesday, NASA engineers began sending commands to the Webb telescope to start extending the DTA. NASA said in a statement that the entire operation took six hours and 39 minutes, ending at 4:24 p.m. EST (2124 GMT).

The James Webb Space Telescope was launched on December 25 and is currently on a 29-day voyage to Lagrange Point 2, a gravitationally stable point 930,000 miles (1.5 million kilometres) distant from Earth. It started building its massive sunshield on Tuesday (Dec. 28), a process that will take around five days.

The five-layer sunshield will keep Webb’s sensors and optics cold, which is essential for the observatory’s infrared-optimized vision of the cosmos.

Webb’s next steps will be to release the sunshield cover and the aft momentum flap, which will “help offset some of the solar pressure that impinges on the large sunshield,” according to NASA. Webb is slated to finish both of these phases on Thursday (Dec. 30), allowing it to start unfolding its sunshield on Friday (Dec. 31).