James Webb Space Telescope passes key review ahead of fall launch

NASA's golden-mirrored James Webb Space Telescope has passed a key review this week, akeymilestone before the $10 billion observatory is launched later this year.

The telescope, which has been peering into the universe for more than 30 years, hadbeen down for afew days last month.

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NASA said initial evidence pointed to a degrading computer memory module as the source of the computer problem.

The technology for the payload computer dates back to the 1980s, and it was replaced during maintenance work in 2009.

The JamesWebbSpaceTelescope's 21 feet 4 inches (6.5 meters) mirror was commanded to fully expand and lock itself into place,NASAsaid, a finaltestto ensure it will survive its million-mile (1.6 million kilometers) journey and is ready to discover the origins of the Universe.

Scott Willoughby, thelead contractor Northrop Grumman, had defined building it as a ''Swiss watch at 40-feet-tall... and getting it ready for this journey that we take into the vacuum at minus 400 degrees Fahrenheit (-240 Celsius), four times further than the Moon."

He was speaking at the company's spaceport in Redondo Beach, California, from where thetelescopewill be shipped to French Guiana to be launched on an Ariane 5 rocket, withNASAtargeting October 31 for liftoff.

Webb's primary mirror is made of 18 hexagonal segments coated with an ultra-thin layer of gold to improve its reflection of infrared light.

It will fly tospacefolded like a piece of origami artwork, which allows it to fit inside a 16-foot (5-meter) rocket fairing, and will then use 132 individual actuators and motors to bend each mirror into a specific position.

Together, the mirrors will function as one massive reflector, to enable thetelescopeto peer deeper into the cosmos than ever before.

Time machine

Scientists want to use thetelescopeto look back in time over 13.5 billion years ago and see for the first time the first stars and galaxies that formed, a few hundred million years after the Big Bang.

To do this, they need to detect infrared. The current premierspacetelescope, Hubble, only has limited infrared capacity.

This iskeybecause, by the time the light from the first objects reaches our telescopes, it has been shifted towards the red end of the electromagnetic spectrum as a result of the Universe extending thespacebetween objects as it expands.

Anotherkeyarea will be the discovery of alien worlds. The first planets to orbit other stars were detected in the 1990s and there are now more than 4,000 exoplanets that have been confirmed.

Webb"has instrumentation that will propel this new and exciting field into its next epic of discovery," said Eric Smith, JamesWebbtelescopeprogram scientist.

Scientists from 44 countries will be able to make use of thetelescope, with proposals including using the infrared capabilities to penetrate the supermassive black holes at the centre of galaxies, including our own.

"The discovery capability ofWebbis limited only by our own imaginations, and scientists around the world will soon be using this general-purpose observatory to take us places we haven't dreamed of going before," said Smith.

(With inputs from agencies)