National Aeronautics and Space Administration scientists, along with Northrop-Grumman Corp. engineers, said the space telescope needs such a sunshield to block heat from the sun so its cameras and instruments can operate properly 1 million miles from the Earth when it launches in 2013.
Blocking light and heat from the sun will keep the observatory operating at cryogenic temperatures, NASA said, enabling its infrared sensors to see distant galaxies, early stars and planetary systems.
The super-tough sunshields are made from a newly developed polymer-based polyimide film, DuPont Kapton E. Each of the five sunshield "membrane" layers is about as thick as a human hair.
NASA said the sunshield must be compactly folded around the telescope in order to fit it into its launch rocket. Once en route to its final orbit, Northrop Grumman engineers will issue commands to the Webb Telescope to unfold the sunshield.
The James Webb Space Telescope is a joint project of NASA and the European and Canadian space agencies.