NASA engineers have successfully completed the deployment of the James Webb Space Telescope's primary mirror, marking the final stage of the spacecraft's two-week deployment process.

James Webb is the largest space telescope ever built, but scientists had to fold the telescope to fit it into the Ariane 5 rocket and send it into space. Since its launch, engineers have been gradually deploying all the major parts of the James Webb.

Eventually, both a tennis court-sized sunshield and a huge mirror were unfolded. The latter consists of 18 primary mirror segments, which will have to collect light from the most distant stars that exploded shortly after the Big Bang, more than 13.5 billion years ago.

The sunshield is also one of the most important parts of the telescope, which was launched on December 25. It is designed to protect the James Webb from radiation from the Sun, Earth, and Moon, and allows the telescope to cool down to very low temperatures. Otherwise, its own infrared radiation will interfere with the infrared light it needs to detect from the most distant objects of the universe.