The gold-plated mirrors of the most powerful telescope ever launched into space clicked into place on Saturday to create an intricate honeycomb pattern nearly 700,000 miles away from earth.
That final crucial stage to create what scientists have called the 21ft “golden eye” of the James Webb Space Telescope means Nasa can now begin looking back in time to try to detect the embers of some of the first stars and galaxies formed after the Big Bang 13.7 billion years ago.
It is also hoped images beamed back to Earth will capture collisions between neutron stars – massive stars that run out of fuel and collapse – that are possibly 25 times the mass of the Sun.
Speaking as the final mirror glided into place to create the honeycomb, Thomas Zurbuchen, NASA’s science missions chief, said: “I’m emotional about it. What an amazing milestone. We see that beautiful pattern out there in the sky now.”
A total of 18 hexagonal mirrors, each coated with 48g of gold to maximise their infrared reflectivity, have now clipped into place.
The mirror is so big that it had to be folded in an orgami-style to fit in the rocket that blasted from South America two weeks ago. The riskiest operation occurred earlier in the week, when the 71ft sunshield unfurled, providing subzero parasole for the mirror and infrared detectors.
Flight controllers in Baltimore began opening the primary mirror on Friday, unfolding the left side like a drop-leaf table.
As the right side snapped into place on Saturday, there was a flurry of applause, but the controllers had to stifle their celebrations as they began remotely locking the mirrors into place.
This mirror is made of beryllium, a lightweight and cold-resistant metal. The hexagonal, coffee table-size segments must be adjusted in the coming days and weeks ahead so they can focus as one.
The telescope should reach its destination 1 million miles away in two weeks’ time. If the mission continues as planned, observations will begin this summer.
Astronomers hope to peer back to within 100 million years of the universe-forming Big Bang. It is hoped the images mission control eventually receives will be far more impressive than those Hubble obtained.
“Before we celebrate, we’ve still got work to do,” NASA said in its live updates. “When the final latch is secure, NASA Webb will be fully unfolded in space.”
Technology developed for the grinding and polishing of the telescope’s mirrors is now used by eye surgeons to create high-definition maps of patients’ eyes.