Space

June 27, 2012

Northrop Grumman-built sunshield on NASA’s Webb Telescope meets fabrication, test milestones

REDONDO BEACH, Calif. – The preflight test layers of NASA’s James Webb Space Telescope sunshield are meeting expected performance targets during tests by engineers at Northrop Grumman.

The company is under contract to NASA’s Goddard Space Flight Center in Greenbelt, Md., for the design and development of Webb’s sunshield, telescope and spacecraft.

One of the most important test milestones was successfully met for template layer five of the tennis-court-sized sunshield that keeps the telescope cold so it can image faint infrared light. Using a laser tracking instrument and a laser radar unit, engineers carefully measured the 3-D shape of the tensioned test layer in two different orientations: face up and rotated 180 degrees so it was face down. They then compared the measurements to an analytical model that predicted how the ultra-thin material will behave in an environment close to zero gravity.

“The as-built and measured membrane was within .36 inches Root-Mean-Squared of the 3-D shape the model predicted, over an area as large as a tennis court, which is remarkable,” explained Jim Flynn, Webb sunshield manager, Northrop Grumman Aerospace Systems. “Our teammate, ManTech International, has done an outstanding job in sunshield fabrication and test. This result validates our ability to manufacture the sunshield layers to meet extremely demanding performance standards.”

The sunshield membrane layers, each as thin as a human hair, are made of Kapton, a tough, high-performance plastic coated with a reflective metal. On-orbit the observatory will be pointed so that the sun, Earth and moon are always on one side, with the sunshield acting as an umbrella to shade the telescope (the mirrors and instruments) from the heat of the sun and warm spacecraft electronics. The sunshield passively cools the telescope to a temperature of -375 degrees F, which is needed to prevent the observatory’s own heat from “blinding” its infrared sensing instruments.

Template layer five is the coldest layer, has the most curved shape and is closest to Webb’s 21 ft. diameter primary mirror. Each sunshield layer has a slightly different 3-D shape, much like the petals of a flower. Each layer will be individually shape-tested to verify its performance on orbit. Shape testing is also under way for two of four template sunshield covers. These covers are coated with silicon to reduce launch and ascent temperatures and protect the folded sunshield layers when they are stowed in the Ariane 5 rocket. Engineers are using the template or test layers to validate processes and performance before fabricating the flight sunshield layers.

Qualification testing was also completed on the gearmotors or actuators that drive the mechanisms that unfurl the sunshield layers while Webb travels to its orbit nearly 1 million miles from Earth. These gearmotors are subjected to tough tests to simulate the effects of extreme temperature changes, vibrations, operating loads and performance over the life of the unit. There are six motors: two drive the sunshield mid-boom telescoping tubes that unfurl the sunshield horizontally out into space; two drive the spooler that opens the two shells that hold the folded layers; and two are used to create the tension that holds the layers in place. Successful completion of qualification testing for the gearmotors demonstrates the engineering design and allows flight hardware manufacturing to proceed.

The James Webb Space Telescope is the world’s next-generation space observatory and successor to the Hubble Space Telescope. Webb will be the most powerful space telescope ever built, observing the most distant objects in the universe, providing images of the first galaxies ever formed and studying planets around distant stars. The Webb telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.




All of this week's top headlines to your email every Friday.


 
 

 

Headlines November 26, 2014

News: When Hagel leaves, new SecDef faces big questions about the military’s futureĀ - President Obama’s new pick to run the Pentagon will face a dizzying set of challenges affecting the Defense Department’s mission, budget and culture. Who will be the next Secretary of Defense?- Following the Nov. 24 surprise announcement from the White House, the...
 
 

News Briefs November 26, 2014

Navy to decommission two more ships in Puget Sound The Navy recently decommissioned the guided missile frigate USS Ingraham at Everett, Wash. It will be towed to Bremerton and scrapped. The Daily Herald reports the Navy also plans to decommission another ship at the Everett homeport and also one stationed in Bremerton. Naval Station Everett...
 
 

NASA airborne campaigns tackle climate questions from Africa to Arctic

NASA photograph The DC-8 airborne laboratory is one of several NASA aircraft that will fly in support of five new investigations into how different aspects of the interconnected Earth system influence climate change. NASA photograph The DC-8 airborne laboratory is one of several NASA aircraft that will fly in support of five new investigations into...
 

 
Air Force photograph by Rick Goodfriend

16T Pitch Boom reactivated to support wind tunnel tests

Air Force photograph by Rick Goodfriend The Pitch Boom at the AEDC 16-foot transonic wind tunnel (16T) was recently reactivated. This model support system is used in conjunction with a roll mechanism to provide a combined pitch...
 
 

Northrop Grumman supports U.S. Air Force Minuteman missile test launch

Northrop Grumman recently supported the successful flight testing of the U.S. Air Force’s Minuteman III intercontinental ballistic missile weapon system. The operational flight test was conducted as part of the Air Force Global Strike Command’s Force Development Evaluation Program. This program demonstrates and supports assessment of the accuracy, availability and reliability of the...
 
 
army-detector

Scientists turn handheld JCAD into a dual-use chemical, explosives detector

Scientists at the U.S. Army Edgewood Chemical Biological Center at Aberdeen Proving Ground, Md., proved it is possible to teach an old dog new tricks by adding the ability to detect explosive materials to the Joint Chemical Age...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>