James Webb Space Telescope fresh off crucial test heading back to Redondo Beach

The honeycomb-shaped, gold-plated mirror of the James Webb Space Telescope, capable of capturing images of distant celestial bodies that emerged 13 billion years ago, has completed crucial tests in Houston and is being prepped to return to its home base at Northrop Grumman Space Park in Redondo Beach.

The first-of-its-kind telescope and perhaps the biggest engineering challenge of this generation emerged recently from a specially designed cryogenic vacuum chamber at NASA’s Johnson Space Center.

It has been sealed there since July while scientists tested whether its 18 folding segments work seamlessly as one giant, 21-foot-wide mirror in concert with its scientific instruments in the frigid, airless conditions of deep space.

For the imaging system to work properly, it has to be completely shielded from the sun and remain at temperatures of at least minus-387 degrees Fahrenheit.

The tests were “an outstanding success,” said Bill Ochs, who leads the project from NASA’s Goddard Space Flight Center in Maryland.

Next, the mirror will be trucked to Northrop Grumman Aerospace Systems for integration with the telescope’s spacecraft, instrument module and sun shield. It’s expected to arrive in early February.

“OTIS [the optical telescope and integrated science instrument module] is in its post cryo-testing de-configuration phase, where it is being readied for installation into the shipping container for the next phase of its journey to Northrop Grumman Aerospace Systems for final integration with the spacecraft element,” said Mark Voyton, manager of the optical telescope and its instruments at Goddard Space Flight Center. “Mirror cleaning is planned for mid-January.”

James Webb Space Telescope’s entire $8.8 billion assemblage has been in the works for 15 years as the successor to Hubble. James Webb is larger and will travel more than 900,000 miles beyond the range of Hubble, which was deployed in 1990 and is expected to continue operating into the 2020s.

Photographing the distant past

The mirror is paired with ultra-sensitive infrared light detectors that will help see beyond the visual realm by relying on extremely sensitive heat-based imaging.

They will have to work perfectly to get the shots scientists are hoping for: Images of the first formations of planetary bodies following the Big Bang.

The system’s three other components also have to function exactly as planned on a trip that’s never been done before after they are launched from French Guiana in spring 2019. The launch was initially set for late 2018 but it was delayed — as launches often are.

Once back in Redondo Beach, the mirror and its instruments will be reunited with the spacecraft bus and sun shield, which were integrated together in a massive High Bay Clean Room in August.

Northrop Grumman engineers have been testing the support systems to ensure they will unfold and deploy exactly as planned.

They practice folding and unfolding the complex equipment in the same way it will unfurl, with the help of engineers on the ground, when it’s released from the rocket’s second stage hundreds of miles beyond Earth.

Space travel preparations

The first thing to deploy after launch will be the sun-shield palettes, followed by the instrument tower and 72-foot-long, hair-thin sun-shield membranes that are roughly the size of a tennis court when fully stretched out. The membranes are coated in aluminum and silicon to absorb heat and will always remain between the mirrors and the sun.

The spacecraft bus will drive the whole system nearly 1 million miles beyond Earth, to the stable second Lagrange point where it can park. The sun shield will block the delicate optical system from the sun’s heat, maintaining temperatures cold enough to liquefy air on one side, while the other side absorbs 185 degree Fahrenheit temperatures and uses the solar energy for power.

A small secondary mirror will reflect light from the main mirror, which will then be combined with readings from infrared cameras and spectrometers.

“Webb will be free of any distortions in astronomical signals caused by Earth’s atmosphere, which distorts and absorbs light, and even emits its own infrared light,” said Paul Geithner, deputy project manager at Goddard Space Flight Center. “Webb’s combination of large optics, location in space, and cold temperature will make it exquisitely sensitive and tremendously powerful.”

Once the whole system is integrated in Redondo Beach, it will be exhaustively tested in preparation for launch.

The mirror has undergone two successive cryogenic tests. The first, at Goddard Space Flight Center in Maryland, subjected it to extreme noise and vibrations that it will experience during launch. For the Houston tests, the air was removed from a cryogenic chamber. Researchers said the mirror and its component scientific instruments performed without a hitch.

NASA, the European Space Agency and the Canadian Space Agency partnered on James Webb, and thousands of scientists and engineers have worked to ensure the success of the mission. The project tests the limits of engineering, and the ultimate goal is to learn how life first emerged in the universe.

Though Hubble travels only about 300 miles beyond Earth, it has managed to capture images as far as 13.2 billion light-years away during its 27-year lifetime.

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