Meet Webb

April 2, 2010

Rheanna Sand

Science in Seconds Blog by Rheanna Sand

The breathtaking, awe-inspiring images from the Hubble and Spitzer Space Telescopes are well known and admired. But in 2014, assuming we all survive armageddon, a new space telescope will be launched - one that is posed to gaze into the very beginning of time.

The James Webb Space Telescope, named after an Apollo mission administrator (yes, administrators can be heroes too) will be the largest space telescope ever launched, with a mirror over two stories high and a sunshield with an area that could, according to NASA, hold 21 cars.

The Webb will also have the most distant orbit - almost a million miles away from Earth! It will sit happily in the second Sun-Earth Lagrange Point, one of five points in our solar system where gravitational forces balance with centripetal forces. This causes the telescope to remain in a fixed position relative to Earth as it orbits, continually facing out to the expanse.

There is much technological wizardry in getting the Webb in space and fully functional. First, it needs to be light enough to launch with conventional rockets, with a mirror large enough to collect long infrared waves that travel so much further than visible light. The solution? Make the telescope expandable - it will be folded in on itself inside the massive Ariane 5 rocket, and once on its own, it will slowly unfurl on a month long journey to its orbit.

The other trick is keeping it cold - not just "deep space" cold, but "near absolute zero" cold. This is where the five-layered silicon coated sunshield comes in, and a fancy two-stage cryocooler that pumps a heat-absorbing gas around the mirrors and infrared detectors. These technologies combined bring the unit a mere 6 degrees away from the theoretical temperature where all motion stops. All in the name of removing heat, which contaminates the delicate images with infrared radiation.

The Webb Telescope, once it's conquered all the hurdles, should give scientists a wealth of information from the furthest reaches of the universe. That is, the scientists who can prove their idea worthy of the Webb's precious hours. But there is no doubt, some astrophysicist somewhere will measure light created just 200 million years after the Big Bang - a snap of a finger in cosmological time.

Hubble, Spitzer: meet Webb.


Science in Seconds Blog by Rheanna Sand



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