NASA said it has completed deploying all the hexagonal mirror segments of its James Webb Space Telescope. The delicate operation to move the $10-billion (roughly Rs. 74,500 crore) space observatory's individual mirror segments out of their launch positions took nearly a week, during which the motors made over a million revolutions. The space agency said engineers sent commands to tiny motors, called actuators, to slowly move each segment about half the length of a paper clip so that each of them is positioned in a way that they have enough space for mirror alignment. Engineers have begun a month-long process to bring the telescope into focus.
The primary mirror of the James Webb telescope comprises 18 hexagonal segments of gold-plated beryllium metal. When all segments are aligned, the mirror measures 21 feet and four inches in diameter. The primary mirror is much larger when compared to the Hubble Space Telescope, which was launched 30 years ago. The more powerful James Webb is set to replace the Hubble soon after its deployment processes are complete.
“The mirror deployment team incrementally moved all 132 actuators located on the back of the primary mirror segments and secondary mirror. The primary mirror segments were driven 12.5mm away from the telescope structure,” said Erin Wolf, Webb program manager at Ball Aerospace, the Colorado-based company which designed and built the telescope's advanced optical technology and lightweight mirror system, in a blog post.
To get a better understanding of how these motors, or actuators, work, NASA previously shared a GIF, explaining the function.
NASA also shared a “fun fact” on Twitter. It said the beryllium metal used in the 18 hexagonal segments of the primary mirror is six times stronger than steel. “But even against beryllium's strength, the motors can actually individually shape the curvature of each mirror segment,” it added.
The 18 segments had been folded together to fit inside an Ariane 5 rocket that carried the telescope to space after the launch on December 25. The telescope is an international collaboration between NASA, European Space Agency, and Canadian Space Agency.