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.


 
 

 
NASA/JPL-Caltech/Univ. of Arizona

NASA’s Opportunity Mars Rover finishes marathon

NASA/JPL-Caltech/Cornell Univ./USGS/Arizona State Univ. This illustration depicts some highlights along the route as NASA’s Mars Exploration Rover Opportunity drove as far as a marathon race during the first 11 years and ...
 
 
NASA/MSFC/Emmett Given

NASA announces teams for 2015 Human Exploration Rover Challenge

NASA/MSFC/Emmett Given Pedaling across a simulated alien landscape of rock, craters and shifting sand is one of the nearly 90 teams of high school, college and university students from across the United States and around the wo...
 
 
Air Force photograph by Joe Davila

F. E. Warren conducts Minuteman III missile test launch from Vandenberg

Air Force photograph by Joe Davila An unarmed LGM-30G Minuteman III intercontinental ballistic missile launches March 23, 2015, at Vandenberg Air Force Base, Calif. The missile was randomly selected from F. E. Warren AFB, Wyo.,...
 

 

NASA awards contract for NOAA’s Joint Polar Satellite System-2 spacecraft

NASA has awarded a delivery order under the Rapid Spacecraft Acquisition III (Rapid III) contract to Orbital ATK (formerly Orbital Sciences Corporation) of Dulles, Va., for the Joint Polar Satellite System (JPSS)-2 spacecraft. The JPSS-2 spacecraft will provide operational continuity of satellite-based observations to enable the National Oceanic and Atmospheric Administration to provide critica...
 
 
University of Colorado image

NASA spacecraft detects aurora, mysterious dust cloud around Mars

University of Colorado image Artistís conception of MAVENís Imaging UltraViolet Spectrograph (IUVS) observing the ìChristmas Lights Aurora” on Mars. MAVEN observations show that aurora on Mars is similar to Earthís &#...
 
 
NASA photograph

Space station crew returns to Earth, lands safely in Kazakhstan

NASA photograph They have landed! This message was posted to the center screen of the Russian Federal Space Agency’s Mission Control Center in Korolev, Russia, the moment confirmation was received that the Soyuz carrying ...
 




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>