James Webb Space Telescope Prepares For Shipment After Final Tests • The Register

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It was a big week for the James Webb Space Telescope (JWST) as the observatory tests were completed and the spacecraft’s shipping operations to the Kourou launch pad began.

It’s been a long time coming – the best part of the 25 years since development began – but it looks like JWST will finally be heading into space this year.

A poster child for cost overruns, JWST is a joint NASA, ESA and CSA project and will observe in a lower frequency range than the veteran Hubble Space Telescope (HST) . Scientists expect the observatory to be able to observe objects too far away for the HST from its L2 location.

The spacecraft is an impressive beast: “100 times more powerful than Hubble,” according to NASA. Its primary mirror consists of 18 hexagonal segments, each 1.32 m in diameter. Six actuators are attached to the back of each segment for focusing (with an additional one in the center of the primary mirror segments to adjust the curvature) and each mirror is aligned 1 / 10,000th the thickness of a hair human.

The mirror should also be kept very cold – down to -220 ° C – and use a lens hood to protect the mirrors and instruments from the sun as well as the heat from the spaceship bus itself.

It all adds up to a hellishly complex spacecraft that has to deploy into space while controllers monitor things from Earth.

Preparations for the expedition are expected to be completed in September and once JWST arrives at the spaceport, launch processing will begin in earnest. The spacecraft will be checked for damage sustained during transport, powered and docked to its Ariane 5 launcher before moving to the launch pad in late November or early December, two days before launch.

Once out of the pad, scientists face a nerve-racking 26 minutes as the telescope takes Ariane 5 into space, followed by a six-month commissioning period. The sunshade will deploy shortly after launch, and in the month it will take for the observatory to reach its intended orbital location, the instruments will be powered up, the telescope cooled, and the mirrors unfolded.

Assuming the launch goes well. NASA’s GAO noted [PDF] “Launch vehicle anomalies” in May. The Ariane 5 has an enviable track record of reliability – its last blackout was in 2002, although a repeat of the whoopsie of 2018, where the satellites were placed in the wrong orbit, would be far from being ideal for the JWST. A hiatus of almost a year occurred between the last Ariane 5 launch, in July, and its predecessor, in August 2020.

Still, the completion of the tests and the initiation of the expedition process is a moment of salvation for scientists, many of whom have devoted much of their careers to the observatory. ®



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