Conclusion of test represents a series of checkpoints to ensure Webb’s mirrors are prepared for long life. Photo Credit: NASA/ Chris Gunn |
The James Webb Space Telescope's 21 feet 4 inch (6.5 meter)
mirror was commanded to fully expand and lock itself into place, NASA said -- a
final test to ensure it will survive its million-mile (1.6 million kilometer)
journey and is ready to discover the origins of the Universe.
"It's like building 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," said
Scott Willoughby of lead contractor Northrop Grumman.
He was speaking at the company's spaceport in Redondo Beach,
California, from where the telescope will be shipped to French Guiana to be
launched on an Ariane 5 rocket, with NASA targeting 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 to space folded 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 the telescope to peer deeper into the cosmos than ever
before.
Time machine
Scientists want to use the telescope to 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
premier space telescope, Hubble, only has limited infrared capacity.
This is key because 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 the space
between objects as it expands.
Another key area 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, James
Webb telescope program scientist.
Scientists from 44 countries will be able to make use of the
telescope, with proposals including using the infrared capabilities to
penetrate the supermassive black holes at the center of galaxies, including our
own.
"The discovery capability of Webb is 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.
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