The backplane of NASA’s James Webb Space Telescope
was mounted to a structure for static load testing to verify it can support the
stiffness required to keep the optics in alignment, and maintain the strength to
support launch loads.
Image Credit:
Northrop Grumman
NASA's James Webb Space Telescope has reached another development milestone
with the completion of static load testing of its primary mirror backplane
support structure (PMBSS) moving the telescope one step closer to its 2018
launch.
The PMBSS is the stable platform that holds the telescope's science
instruments and the 18 beryllium mirror-segments that form the 21-foot-diameter
primary mirror nearly motionless while the telescope peers into deep space. The
primary mirror is the largest mirror in the telescope -- the one starlight will
hit first.
"Static testing demonstrates the backplane has the structural integrity to
withstand the forces and vibrations of launch and is the final test prior to
starting the integration of the backplane with the rest of the telescope," said
Lee Feinberg, NASA’s Optical Telescope Element manager at the agency’s Goddard
Space Flight Center in Greenbelt, Maryland.
The Northrop Grumman Corporation and ATK of Magna, Utah, completed the
testing before delivering the structure to Northrop Grumman's facilities in
Redondo Beach, California.
"This is the largest, most complex cryogenically stable structure humans have
ever built," said Scott Texter, Optical Telescope Element manager for Northrop
Grumman. "Completion of the static testing verifies it can hold the weight it is
designed to hold. Now the structural backbone of the observatory is officially
verified and ready for integration."
Despite its size and complexity, the PMBSS is one of the most lightweight
precision-alignment truss structures ever designed and built. When fully
deployed, it measures approximately 24 feet tall by 19.5 feet wide by more than
11.5 feet deep, and weighs only 2,180 pounds. Once fully assembled and
populated, the PMBSS will support a mission payload and instruments that weigh
more than 7,300 pounds. With a full launch load, it will support the equivalent
of 12 times its own weight.
The PMBSS is designed to minimize changes in the shape of the telescope
caused when one side is hotter than the other. While the telescope is operating
at a range of extremely cold temperatures, between -406 and -343 degrees
Fahrenheit, the backplane must not move more than 38 nanometers, approximately
1/1,000 the diameter of a human hair.
Under contract from NASA, Northrop Grumman is the lead contractor for the
design and development of the Webb telescope's optics, sunshield and spacecraft.
ATK designed, engineered and constructed more than 10,000 parts for the PMBSS at
its facilities in Magna. They used composite parts, lightweight graphite
materials, state-of-the-art material sciences and advanced fabrication
techniques to build the structure.
The next step for the space telescope is to integrate the composite
structures with the deployment mechanisms to create the overall Optical
Telescope Element (OTE) structure. The OTE structure will then be shipped to
Goddard for integration with the mirrors. NASA and Northrop Grumman will perform
cryogenic testing of the PMBSS structure after mirror integration is
complete.
The James Webb Space Telescope is the world's next-generation space
observatory and successor to NASA's Hubble Space Telescope. Designed to be the
most powerful space telescope ever built, Webb will observe the most distant
objects in the universe, provide images of the first galaxies formed and see
unexplored planets around distant stars. The Webb telescope is a joint project
of NASA, the European Space Agency and the Canadian Space Agency.
For more information about NASA's James Webb Space Telescope, visit:
NASA
Guillrmo Gonzalo Sánchez Achutegui
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