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-hubble

NASA unveils celestial fireworks as official image for Hubble 25th Anniversary

The brilliant tapestry of young stars flaring to life resemble a glittering fireworks display in the 25th anniversary NASA Hubble Space Telescope image, released to commemorate a quarter century of exploring the solar system an...
 
 
NASA illustration

NASA awards radiation challenge winners, launches next round

NASA illustration This illustration depicts our heliosphere, showing the approximate locations of Voyager 1 and Voyager 2 spacecraft. Galactic cosmic rays originate outside the heliosphere and stream in uniformly from all direc...
 
 
NASA photograph

Celebrate with NASA as agency commemorates Hubble’s 25th anniversary

NASA’s Hubble Space Telescope is turning 25 this year. The observatory has transformed our understanding of our solar system and beyond, and helped us find our place among the stars. NASA is celebrating the Hubble Space T...
 

 

ULA unveils America’s new rocket

https://www.youtube.com/watch?v=emmeil-0u5k&feature=player_embedded United Launch Alliance unveiled its Next Generation Launch System April 13 at the 31st Space Symposium. The new rocket, Vulcan, will transform the future of space by making launch services more affordable and accessible. The NGLS brings together decades of experience on ULA’s reliable Atlas and Delta vehicles, combin...
 
 
NASA/JHU APL/Carnegie Institution of Washington

NASA spacecraft achieves unprecedented success studying Mercury

NASA/JHU APL/Carnegie Institution of Washington NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft traveled more than six and a half years before it was inserted into orbit around Merc...
 
 

NASA selects American small business, research institution projects for further development

NASA has selected 149 research and technology proposals from American small businesses and research institutions that will enable NASA’s future missions into the solar system and beyond while benefiting America’s technology-driven economy right here on Earth. The selected proposals now will enter into negotiations for contract awards as part of Phase II of the agency’s...
 




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>