Tabatha Thompson/Grey Hautaluoma
Headquarters, Washington
202-358-3895/0668
Rob Gutro
Goddard Space Flight Center, Greenbelt, Md.
301-286-4044
RELEASE: 07-014
NASA CREATES MICROSCOPIC TECHNOLOGY FOR WEBB SPACE TELESCOPE
GREENBELT, Md. - NASA engineers and scientists building the James Webb
Space Telescope have created a new telescope technology called
"microshutters." Microshutters are tiny doorways the width of a few
hairs that will allow the telescope to view the most distant stars
and galaxies humans have ever seen.
The microshutters will enable scientists to mask unwanted light from
foreground objects so the telescope can focus on the faint light of
the first stars and galaxies that formed in the universe. Only the
Webb Telescope has this technology. The Webb Telescope will launch in
the next decade.
In December 2006, the microshutters passed crucial environmental
testing to demonstrate that they can withstand the rigors of
launching and placement in deep space. NASA's Goddard Space Flight
Center, Greenbelt, Md., designed, tested and built the instrument
technology. The microshutters will work in conjunction with the
telescope's Near Infrared Spectrograph that is being built by the
European Space Agency.
"To build a telescope that can peer farther than the Hubble Space
Telescope can, we needed brand new technology," said Murzy Jhabvala,
chief engineer of Goddard's Instrument Technology and Systems
Division. "We've worked on this design for more than six years,
opening and closing the tiny shutters tens of thousands of times to
perfect the technology."
Each of the 62,000 shutters measures 100 by 200 microns, or roughly
the width of three to six human hairs. The shutters are arranged in
four identical grids that have a layout of 171 rows by 365 columns.
These shutter grids are in front of an eight million-pixel infrared
detector that records the light passing through the open shutters.
The detector itself represents a technology breakthrough.
Astronomers using ground-based telescopes first take a picture of the
sky and map all the objects in which they are interested. They then
create a mask resembling a sieve to place on the telescope so that
only the light from areas of interest can reach the telescope's
detectors.
In space, the Webb Telescope will have a wide field of view, and its
deep, long observation of the sky will contain millions of light
sources. Microshutters allow scientists to remotely and
systematically block out light that they do not want, allowing the
large-format detector to measure infrared spectra optimally.
Previously, masks of space telescopes only covered large regions of a
field of view at any one time.
"The microshutters provide a conduit for faint light to reach the
telescope detectors with very little loss," said Harvey Moseley, the
Microshutter Principal Investigator at Goddard. "The shutters allow
us to perform spectroscopy on up to 100 targets simultaneously. We
will be able to see deeper in less time."
Each shutter grid array is etched from a single piece of silicon,
leaving a sculpture of cavities and doorframes with microscopic
hinges and moving doors. The tiny shutters are laced with magnetic
cobalt-iron strips.
A passing magnet will open all the doors, pulling them down into the
cavity. While the doors are opened, engineers can apply a combination
of voltages to keep the selected microshutters open. The remainder
close when the magnet moves away.
The microshutters must perform at a temperature of minus 388 degrees
Fahrenheit (40 Kelvin, -233 degrees Celsius), which is the
temperature of the Near Infrared Spectrograph.
The microshutters are needed for observing distant, faint sources.
Hubble's Ultra-Deep Field provides the deepest view of the universe,
an image containing tens of thousands of light sources. Some of these
light sources are relatively close and some are from an era just
after galaxies and stars formed. To go deeper, scientists need to
mask the brighter, closer sources and focus only on the most distant.
The same microshutter technology also will efficiently reveal faint
features in relatively nearby star fields, where scientists will
analyze multiple sources at once.
"The microshutters are a remarkable engineering feat that will have
applications both in space and on the ground, even outside the realm
of astronomy in biotechnology, medicine and communications," said
Moseley.
For diagrams and images of the microshutters, visit:
http://www.nasa.gov/vision/universe/starsgalaxies/microshutters.html
-end-
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