The launch of the James Webb Space Telescope is only days away. Scheduled for lift off on 24 December, the largest and most complex space observatory ever built will be sent to an orbit beyond the moon.

James Webb is so huge that it has had to be folded up to fit in the rocket. There will be a tense two weeks over Christmas and the New Year as the space giant unfurls and unfolds. Its design and construction has taken about 30 years under the leadership of NASA’s Goddard Space Flight Center.

With its huge 6.5 metre-wide primary mirror, the giant observatory promises to extend our view across the cosmos to the first stars to shine in the early universe. That’s a vista of Cosmic Dawn: the first small clusters of stars to form and ignite out of what had been a universe of just dark clouds of primordial gas. If the James Webb succeeds in capturing the birth of starlight, we will be looking at celestial objects more than 13.5 billion light years away.

Closer to home, the telescope will also revolutionise our understanding of planets orbiting stars beyond the solar system.

BBC science correspondent Jonathan Amos reports from the European Space Agency’s launch site in French Guyana from where James Webb will be sent into space. He talks to astronomers who will be using the telescope and NASA engineers who’ve built the telescope and tested it in the years leading to launch.

Producer: Andrew Luck-Baker

BBC Inside Science is made in association with the Open University.

Image: James Webb Space Telescope. Credit: Adriana Manrique Gutierrez, NASA animator