Measuring the size of a tennis court, the James Webb Space Telescope's sunshield has been meticulously folded one final time. This precision engineering milestone advances preparations for its October launch.
As one of the most anticipated space observatories, the James Webb Space Telescope (JWST) is optimized for infrared wavelengths, perfect for studying the early universe. Detecting faint heat signals from distant objects demands near-total isolation from stray heat sources.
Positioned at the L2 Lagrange point, 1.5 million kilometers from Earth away from the Sun, the telescope relies on a sunshield 22 meters long by 11 meters wide, made of five ultra-thin, highly reflective layers.
This structure keeps the primary mirror shaded at temperatures around -223°C. Select instruments achieve even colder -258°C via active cooling systems.
Engineers at Northrop Grumman in Redondo Beach, California, recently completed folding and stowing the sunshield to fit within the Ariane 5 rocket's 5.4-meter-diameter fairing.
“There's nothing quite like folding a tennis court-sized sunshield, but it's akin to packing a parachute,” explains Jeff Cheezum, lead designer. “Just as a skydiver relies on a properly packed parachute for flawless deployment, JWST needs its sunshield stowed perfectly to deploy and hold shape in space.”
The month-long process started with laying the five layers flat, per NASA details. Layers were then elevated on supports for precise folding into accordion-like stacks flanking the telescope.
The outermost layer is just 0.005 cm thick, with inner layers half that thickness, posing unique handling challenges. The 90 tension cables were also precisely stowed for deployment.
Aligning membrane stacks was particularly intricate: each layer features hundreds of holes to block light and heat from optics. Technicians aligned these during folding, inserting 107 pins to secure layers for launch and aid unfolding in orbit.
Over the next three months, teams will finalize securing the sunshield, which remains stowed until deployment in space.
