Saturday, February 13, 2010

JWST Sunshield Passes Critical Design Review

Image comment: This is a photo of the 1/3 scale sunshield membranes undergoing final inspection at the Nexolve facility in Hunstville, Alabama. The full-scale sunshield will fly on the JWST in 2014
Image credits: Nexvolve

The James Webb Space Telescope (JWST) will be the largest observation instrument ever delivered into space during a single rocket launch. Only the International Space Station (ISS) will exceed it in size, but it will come nowhere near its capabilities of observing the early Universe in infrared wavelengths. But, in addition to the difficulties associated with deploying such a behemoth into orbit, engineers also need to figure out a way of protecting its highly sensitive instruments from stray radiation coming from the Sun, the Earth or the Moon. And this is where the shield steps in.

The sunshield the JWST will employ is about the size of a tennis court, and is made up of five overlapping layers of material. Its mission is fairly straightforward, namely to prevent any photons from entering the telescope's mirrors. Just recently, the shield passed a design review test, the most important it had to face. The investigation determined that the design stage was complete, and that the structure met mission requirements. It is being developed by Northrop Grumman, a corporation that has been contracted by the NASA Goddard Space Flight Center, in Greenbelt, Maryland.

The tests took place between January 11-14, in Redondo Beach, California. “Passing this review is the culmination of years of intense effort meeting the unique challenges that have defined this mission. This is the first time a sunshield of this size and complexity will fly on a space telescope. We've achieved a very significant mission-critical milestone with this important validation of our sunshield design,” Northrop Grumman Aerospace Systems JWST telescope Program Manager Scott Willoughby says. The current design achieved thermal, deployment and stray-light targets, and is therefore ready to enter the manufacturing stage.

“There are no text books or guidelines on how to design and build a deployable sunshield of this size. Nearly a decade ago NASA and Northrop Grumman had to start from scratch and literally invent the techniques, materials, and mechanisms needed to do the job. We still have quite the challenge in front of us now that we start into the fabrication and testing phase but it's also a very exciting time,” GSFC JWST telescope sunshield Manager Keith Parrish shares. He adds that the tests consisted of 18 separate sub-assembly design audits, which were aimed at analyzing the performance of individual systems. Another thorough study was conducted on the points where these systems interlaced.

The Webb telescope is NASA's next-generation premier space observatory, exploring deep space phenomena from distant galaxies to nearby planets and stars. The Webb telescope will give scientists clues about the formation of the Universe and the evolution of our own solar system, from the first light after the Big Bang to the formation of star systems capable of supporting life on planets like the Earth. Expected to launch in 2014, the telescope is a joint project of NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA).