NASA's new space telescope will be available to scientists in 44 countries shortly after its launch

NASA's giant Webb Space Telescope has successfully passed key pre-launch tests.

The world's largest and most powerful space telescope unfurled its giant golden mirror on Earth for the last time Wednesday, a key milestone ahead of the $10 billion observatory's launch later this year.

The James Webb Space Telescope's 6.5-meter mirror was ordered to unfold fully -- a final test to ensure it can survive a journey of about 1.6 million kilometers and be ready to discover the origins of the universe, NASA said.

"It's like building a 40-foot Swiss watch..." said Scott Willoughby of Northrop Grumman Corp., the prime contractor. And prepare it to travel to a vacuum of minus 400 degrees Fahrenheit, more than four times the distance between the Earth and the moon."

He was speaking from the company's space launch site in Redondo Beach, California, the report said. From there, the telescope will be transported to French Guiana for liftoff aboard an Ariane 5 rocket, which NASA has now set for Oct. 31.

Weber's main mirror is made up of 18 hexagonal mirrors coated with an ultrathin layer of gold to enhance the reflection of infrared light, the report said.

It will fly into space in a folded form like a piece of origami -- allowing it to fit into a rocket fairing about five metres in diameter -- and will then use 132 separate motors to bend each mirror into a specific position.

Together, these small mirrors will form a giant reflector, allowing the telescope to peer deeper into the universe than ever before.

Scientists hope to use the telescope to look back 13.5 billion years into the universe and see for the first time the first stars and galaxies that formed hundreds of millions of years after the Big Bang.

To do this, you need to detect infrared light. The current leading space telescope, the Hubble Space Telescope, has only limited infrared detection capabilities.

This is key, because by the time the light from the first stars reached our telescope, it had shifted to the red end of the electromagnetic spectrum, because the universe expanded the space between the stars as it expanded.

Another key area will be the discovery of alien worlds. Planets orbiting other stars were first discovered in the 1990s, and more than 4,000 exoplanets have been identified.

The Webb Space Telescope "has instruments that will drive the next epic of discovery in this exciting new field," said Eric Smith, project scientist for the James Webb Space Telescope.

Scientists from 44 countries will be able to use the telescope, the report said, and their proposals include using infrared detection capabilities to understand supermassive black holes at the centers of galaxies, including the Milky Way.

"Webb's discovery is only limited by our own imaginations," Smith said. "Scientists around the world will soon be using this multi-purpose observatory to take us places we never dreamed of going."