New Technologies for James Webb Space Telescope Approved Early
This is one mirror segment. 18 mirror segments will form a single large mirror with a total area of 25 square-meters (almost 30 square yards) when they come together. Credit: NASA
More than a year ahead of schedule, a team of independent
experts has approved all ten new technologies developed for NASA's
James Webb Space Telescope. Many of the technologies are
revolutionary and have never before been used on any satellite or
space telescope. The early approval can reduce the risk of increased
costs and schedule delays before the program is approved for further
NASA commissioned the team of engineers, scientists and project
managers to conduct the technical review. The group evaluated the
telescope's near and mid-infrared detectors, sunshield materials,
lightweight cryogenic mirrors, microshutter arrays, cryogenic
detector readout application-specific integrated circuits, cryogenic
heat switches, a large precision cryogenic structure, a cryocooler
for the mid-infrared instrument, and wavefront sensing and control.
They determined the technologies were tested successfully in a
space-like environment and are mature enough to include on the
telescope's upcoming mission.
The actual hardware and software that will fly on the telescope now
can be engineered from working prototypes. These technologies will
allow the observatory to peer back in time to about 400 million years
after the Big Bang, enabling scientists to study the first generation
of stars and galaxies.
"The technology non-advocate review was our attempt to address one
common problem that NASA missions encounter that leads to cost
growth," said Eric Smith, Webb program scientist at NASA
Headquarters, Washington. "That problem is late maturation of
technology in a program's life-cycle. By conducting an external
review of our technologies more than a year ahead of the Preliminary
Design Review - when they are traditionally examined - we hope to
better manage that aspect of the program's costs."
This is an array of microshutters, about the size of a postage stamp. These tiny shutters are arranged in a waffle-like grid containing over 62,000 shutters. Credit: NASA/Chris Gunn
Microshutters are tiny cells that measure 100 by 200 microns, or about the width of three to six human hairs. This is a closeup view of the microshutters. Credit: NASA
Two examples of the new technologies are the microshutter arrays and
wavefront sensing and control.
The wavefront sensing and control system calculates the mirror adjustments required to bring an image into focus. Ball Aerospace engineered a scaled telescope testbed, shown here, so that wavefront sensing and control can be developed and tested. Credit: NASA
Microshutters are tiny doorways, the width of a few hairs, that will
allow scientists to remotely and systematically block out unwanted
light and view the most distant stars and galaxies ever seen. The
telescope will be the first project to employ this technology.
Through a process called wavefront sensing and control (a set of
algorithms and software programs), the optimum position of each of the
telescope mirrors will be computed, and the positions will be
adjusted as necessary, causing the individual mirrors to function as
one very sensitive telescope.
"At the inception of the James Webb Space Telescope program, NASA
adopted a strategy of making significant, early investments in the
development of the diverse and challenging new technologies needed to
conduct the mission," said Phil Sabelhaus, project manager at
Goddard. "Receiving the review board's confirmation that we have met
the goal more than a year early for all of our new technologies is a
major accomplishment for our team and a tribute to the benefits of
the early investment strategy," Sabelhaus said.
The James Webb Space Telescope is expected to launch in 2013. The
telescope is a joint project of NASA, the European Space Agency and
the Canadian Space Agency.