NASA begins the process of aligning mirrors on the James Webb Space Telescope

NASA has started a painstaking, months-long process to develop its new James Webb Space Telescope.

The process of aligning the mirrors is a task that must be completed in time for the revolutionary eye in the sky to peer into the cosmos by early summer.

Mission control engineers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, began by sending their initial commands to tiny motors called actuators that slowly position and adjust the telescope’s main mirror.

Made up of 18 hexagonal segments of gold-plated beryllium metal, the main mirror measures 6.5m in diameter – a much larger light-collecting area than Webb’s predecessor, the Hubble Space Telescope.

The 18 segments, which had been folded together to fit inside the hold of the rocket that carried the telescope into space, were deployed along with the rest of its structural components for a period of two weeks after the Webb launch on December 25, 2021.

These segments must now be detached from the clips that held them in place for launch, and then moved half an inch from their original configuration – a 10 day process – before they can be aligned to form a single surface. , uninterrupted and collecting light. .

Lee Feinberg, components manager of the Webb Optical Telescope at Goddard, said the alignment will take an additional three months. And aligning the primary mirror segments to form a large mirror means that each segment “is aligned to one five-thousandth of the thickness of a human hair,” Feinberg said.

“All of this forced us to invent things that had never been done before,” like actuators, which were designed to move gradually at 240 ° C in the vacuum of space, he added. .

The telescope’s smaller secondary mirror, designed to direct light collected from the primary lens to Webb’s camera and other instruments, must also be aligned to function as part of a coherent optical system.

According to Feinberg, if all goes as planned, the telescope should be ready to capture its first scientific images in May; they will be processed for about a month before they can be made public.

The $ 9 billion (£ 6.5 billion) telescope, described by NASA as the premier space science observatory for the next decade, will primarily observe the cosmos in the infrared spectrum, allowing it to look through clouds Of gas and dust where the stars are born. . Hubble operated primarily at optical and ultraviolet wavelengths.

Webb is about 100 times more powerful than Hubble, NASA engineers said, allowing him to observe objects at greater distances, and therefore further in time, than Hubble or any other telescope.

Astronomers say it will provide a glimpse into the cosmos never seen before – dating only 100 million years after the Big Bang, the theoretical flashpoint that triggered the expansion of the observable universe about 13 years ago, 8 billion years.

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