Saturday, May 16, 2009

Live In Orbit: Hubble's "Contact Lenses" Removed

A refrigerator-sized instrument that revived the Hubble Space Telescope after its darkest days was removed from the observatory today after serving as "contact lenses" for 16 years.

Anchored to the end of the shuttle's robot arm, Atlantis mission specialist Drew Feustel latched onto towel-bar handle on the Corrective Optics Space Telescope Axial Replacement, or COSTAR.

The 850-pound device was devised in the early 1990s to correct for the debilitating flaw discovered in the telescope's 94.5-inch primary mirror two months after its April 1990 launch. The mirror was ground to the wrong prescription, so it didn't focus light properly.

The COSTAR instrument contains a series of small mirrors that sharpen the focus before light enters Hubble spectrographs -- non-optical instruments that break light into its component parts so scientists can gauge the chemical make-up of stars, galaxies and other celestial objects.

Now all of Hubble's instruments have built-in corrective optics, so the COSTAR no longer is needed. The COSTAR will be temporarily stowed on a fixture in the shuttle's cargo bay. The astronauts later today will be pack it in a protected carrier for a return trip to Earth.

Next up: the astronauts will install the Cosmic Origins Spectrograph in the slot were COSTAR had been housed. The COS will be the most sensitive ultraviolet spectrograph ever flown on Hubble. It will probe the large scale structure of the universe and is expected to shed unprecedented light on the mysterious dark matter that makes up 90 percent of the cosmos.

You can watch the action unfold here in The Flame Trench. Simply click the NASA TV box at the righthand side of the page to launch our NASA TV viewer, and be sure to refresh this page for periodic updates.

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