NASA's new space telescope opened its huge, gold-plated, flower-shaped mirror Saturday, the final step in the observatory's dramatic unfurling.
The last portion of the 21-foot (6.5-meter) mirror swung
into place at flight controllers' command, completing the unfolding of the
James Webb Space Telescope.
“I'm emotional about it. What an amazing milestone. We see
that beautiful pattern out there in the sky now,” said Thomas Zurbuchen, chief
of NASA's science missions.
More powerful than the Hubble Space Telescope, the $10
billion Webb will scan the cosmos for light streaming from the first stars and
galaxies formed 13.7 billion years ago. To accomplish this, NASA had to outfit
Webb with the largest and most sensitive mirror ever launched — its “golden
eye,” as scientists call it.
Webb is so big that it had to be folded orgami-style to fit
in the rocket that soared from South America two weeks ago. The riskiest
operation occurred earlier in the week, when the tennis court-size sunshield
unfurled, providing subzero shade for the mirror, and infrared detectors.
Flight controllers in Baltimore began opening the primary
mirror Friday, unfolding the left side like a drop-leaf table. The mood was
even more upbeat Saturday, with peppy music filling the control room as the
right side snapped into place.
After applauding, the controllers immediately got back to
work, latching everything down. They jumped to their feet, exchanged high-fives
and cheered from behind masks when the operation was finally complete 2 1/2
hours later, doing their best to remain socially distant because of the global
surge in COVID-19 cases.
“We have a deployed telescope on orbit, a magnificent
telescope the likes of which the world has never seen,” Zurbuchen said,
congratulating the team. “So how does it feel to make history, everybody? You
just did it.”
His counterpart at the European Space Agency, astronomer
Antonella Nota, noted that after years of preparation, the team made everything
look “so amazingly easy.”
“This is the moment we have been waiting for, for so long,”
she said.
Webb's main mirror is made of beryllium, a lightweight yet
sturdy and cold-resistant metal. Each of its 18 segments is coated with an
ultra thin layer of gold, highly reflective of infrared light. The hexagonal,
coffee table-size segments must be adjusted in the weeks ahead so they can
focus as one on stars, galaxies and alien worlds that might hold atmospheric
signs of life.
“It's like we have 18 mirrors that are right now little
prima donnas all doing their own thing, singing their own tune in whatever key
they're in, and we have to make them work like a chorus and that is a
methodical, laborious process," operations project scientist Jane Rigby
told reporters.
Webb should reach its destination 1 million miles (1.6
million kilometres) away in another two weeks; it's already more than 667,000
miles (1 million kilometres) from Earth since its Christmas Day launch. If all
continues to go well, science observations will begin this summer. Astronomers
hope to peer back to within 100 million years of the universe-forming Big Bang,
closer than Hubble has achieved.
Project manager Bill Ochs stressed the team isn't letting
its guard down, despite the unprecedented successes of the past two weeks.
“It's not downhill from here. It's all kind of a level
playing field," he said.
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