The recently deployed James Webb Space Telescope has completed a key milestone in preparing it for future science operations: deploying its 70-foot sunshield.
The sunshield was folded to fit inside the payload area in the nose cone of an Arianespace Ariane 5 rocket and is about the size of a tennis court when fully extended. Nasa’s team began remotely deploying the sunshield on December 28, 2021, and completed the mission over a span of eight days.
“This is the first time anyone has ever attempted to put a telescope this large into space,” said Thomas Zurbuchen, the associate administrator for NASA’s Science Mission Directorate at the agency’s headquarters in Washington. “Webb required not only careful assembly but also careful deployments. The success of its most challenging deployment – the sunshield – is an incredible testament to the human ingenuity and engineering skill that will enable Webb to accomplish its science goals.”
The sunshield, made up of five layers, protects the telescope from the heat and light of the Sun, Moon, and Earth. Each sheet is made of plastic and is about as thin as human hair, coated with reflective metal. This provides protection of about 1000 SPF. The layers all work together to convert over 200 kilowatts of solar energy to a fraction of a watt.
The unfolding and tensioning process required the use of 70 hinge assemblies, about 400 pulleys, 90 individual cables totaling about a quarter of a mile in length, and eight deployment motors.
The telescope’s complete set-up process will still take another 5 ½ months, including the deployment of the secondary mirror and primary mirror wings, calibration of the science instruments, and alignment of the telescope optics. Then, Webb will be able to deliver its first images.
“This is unbelievable. We are now at a point where we’re about 600,000 miles from Earth, and we actually have a telescope,” said Bill Ochs, who is the project manager for the James Webb Space Telescope. “So, congratulations to everybody.”