Telescope’s sensors designed, tested in Hawaii

This March 5, 2020 photo made available by NASA shows the main mirror assembly of the James Webb Space Telescope during testing at a Northrop Grumman facility in Redondo Beach, Calif. (Chris Gunn/NASA via AP)
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A new NASA telescope is scheduled to launch Christmas Eve with sensors designed by University of Hawaii astronomers.

The James Webb Space Telescope, the planned $10 billion successor to the Hubble Space Telescope, is designed to observe fainter and more distant objects using equipment designed and tested by UH’s Institute for Astronomy.

Included within the telescope are 16 near-infrared sensors called HAWAII-2RGs, which were designed in Hawaii and tested partly on Maunakea, and allow the telescope to capture near-infrared light, wavelengths of light just beyond the range of human sight.

“The idea behind these sensors comes from (UH astronomer) Don Hall,” said IFA associate astronomer Roy Gal. “We don’t have the capacity to fabricate these sensors here, but we made the designs here, sent them somewhere else for fabrication, and then we did the testing here.”

Hall, who died in March 2020, developed the sensors over years using a combination of mercury, cadmium and tellurium.

The composition of the sensors allows them to operate at higher temperatures than competing sensors.

The margin of superiority for the HAWAII-2RGs is nearly infinitesimal — only one or two degrees, Gal said. But when the telescope is operating at temperatures close to absolute zero — the temperature at which all energy effectively ceases — one or two degrees is monumental.

“Heat sources like the atmosphere give off infrared light, which means you have to cool the detectors periodically so they can be effective,” Gal said. “So the less you have to do that, the better.”

The James Webb Space Telescope has been in the works for years, with an initial planned launch in 2007. Since then, costs have ballooned from about $500 million to about $9.7 billion, and the launch date pushed back by more than a decade.

Earlier this month, the launch date was pushed back yet again from Dec. 22 to Dec. 24. Assuming all goes well, the telescope will launch from a facility in French Guiana at 4:20 a.m. HST.

“I have absolute faith in our technology and NASA’s capabilities,” UH astronomer Klaus Hodapp, who also helped develop and test the sensors, said in a statement. “But this is an extremely complicated endeavor.

“For those of us involved with JWST, it’s months of nervous anticipation from launch to deployment a million miles away in space, to the unfolding of the instrument and eventual successful activation of the telescope.”

Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.