Sunshield Pathfinder
The pathfinder will undergo folding and deployment trials through 2007 to verify its design concept and deployment techniques. The pathfinder is one in a series of engineering models built by Northrop Grumman and its JWST team to reduce risk on the program. The sunshield membrane material successfully completed Technology Readiness Level-6 (TRL) 6 (testing in the relevant operational environment) in April 2006.
The five-layer sunshield consists of thin membranes made from a polymer-based film and supporting equipment such as spreader bars, booms, cabling, and containment shells. Designed to block solar light and keep the Observatory operating at cryogenic temperatures, the sunshield will help enable the Webb Telescope's infrared sensors to see distant galaxies, early stars and planetary systems, and help astronomers better understand dark matter.
"We've developed pathfinders, engineering models and test articles for many of the Webb Telescope's systems to better understand their performance and reduce program risk," said Martin Mohan, Northrop Grumman Space Technology's JWST program manager. "Our acquisition strategy is to complete development of high risk items early in the program, so that we minimize challenges when we build and test the actual flight hardware."
A pathfinder is critical to verify analytical modeling assumptions, because it is difficult to predict the behavior of the flexible thin film using only computer-aided design tools. Measuring 40 feet by 65 feet, the sunshield is very large, and details such as cabling tension, surface figure and folding methods require testing on a full-size model.
The sunshield pathfinder is the latest in a series of engineering models built by Northrop Grumman and its JWST team to reduce risk on the program. Other pathfinders built for the Webb Telescope include a telescope test bed; full, half and one-third scale models of the Observatory; a mirror segment engineering development unit and backplane test article.
