James Webb Telescope Sunshield complete: Nasa unfurls a 1,000,000 SPF umbrella

The Sunshield is designed to protect the delicate instruments on board the James Webb Space Telescope - the $18bn successor to the Hubble telescope

Nasa has published the first picture of the the Sunshield – the five-layered, kite-shaped membrane that will eventually protect the James Webb Space Telescope from the heat of the Sun as it sails through space.

The Webb telescope (named in honour of Nasa’s second administrator) is the $8 billion successor to the Hubble and upon completion will be the most powerful space telescope ever built.

It’s scheduled to launch in 2018, with the Sunshield being used to block out infrared rays and heat from the Sun that might interfere with the telescope's delicate instruments.

From Nasa: “The Sunshield is about the length of a tennis court, and will be folded up like an umbrella around the Webb telescope’s mirrors and instruments during launch.

“Once it reaches its orbit, the Webb telescope will receive a command from Earth to unfold, and separate the Sunshield's five layers into their precisely stacked arrangement with its kite-like shape.”

And how good is the protection that the Sunshield offers? According to Nasa it has a sun protection factor or SPF of around 1,000,000 – enough to keep the Webb telescope at a frosty -370 degrees Fahrenheit (-223 Celsius).