James Webb Space Telescope ready for Christmas liftoff

Ariane 5 rocket launch scheduled for 7:20 a.m. ET on Christmas

The $11 billion James Webb Space Telescope designed to revolutionize our knowledge of the universe is ready for its Christmas delivery into orbit.

On Thursday, Webb's ride to space, the Ariane 5 rocket, was slowly and carefully rolled out to the launchpad at the European Spaceport in Kourou, French Guiana. Like a wrapped present, the 21-foot-in diameter telescope was safely folded and stowed inside the rocket's nosecone. The specially-designed fairings have environmental controls that keep Webb at the perfect temperature and humidity during its final days on Earth.

The 173-foot tall Ariane 5 rocket made the journey to the launchpad surrounded by the lush jungle greenery of South America and pulled by a small German-made blue TITAN truck. The rocket will undergo final health checks, including electrical and software configurations, at the launch pad.

Liftoff is scheduled for Saturday on Christmas morning between 7:20 a.m. and 7:52 a.m. ET. Live coverage of the launch begins at 6 a.m. ET on NASA TV and FOX Weather.

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The launch was delayed several times in December because of technical issues, then from Christmas Eve to Christmas Day due to weather around the tropical launch site. Launch officials say the weather has improved.

Before liftoff, the rocket will be filled with liquid oxygen and liquid hydrogen fuel. Webb will switch to internal battery power about 20 minutes before leaving the planet.

Webb's journey to this moment has been 25 years in the making. Astronomers hope Webb will be the gift that continues to give even to next-generation scientists.

The telescope is a collaboration between NASA, the European Space Agency and the Canadian Space Agency, and other international partners.

Webb is designed to use infrared and visible light to see back to the birth of stars and when the first galaxies formed 13.5 billion years ago, a few hundred million years after the big bang. The telescope will also look closer to home, including our planets, and study exoplanets or worlds outside our solar system.

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It's the largest, most powerful telescope ever built with a sun shield the size of a tennis court and a mirror comprised of 18 gold-plated hexagonal mirrors that make up the golden honeycomb shape of the 21-foot primary mirror.

About 27 minutes after liftoff, Webb will be on its own in space. Three days after launch, the spacecraft will begin to unwrap itself, starting with the five-layer sunshield. Two weeks post-launch, the hexagon mirror segments will assemble to form the large primary mirror.

Webb is scheduled to arrive at its final destination 1 million miles from Earth about 29 days later.