News Service from House Harris

US: US astronauts equip Hubble on third spacewalk

HOUSTON, Texas, May 16 AFP - Two US astronauts are coming to the end of their third spacewalk after reviving a crippled camera on the aging Hubble Space Telescope and equipping the 19-year-old observatory with a new key instrument.

Astronauts John Grunsfeld and Drew Feustel are finishing up work on decking out Hubble in a bid to extend its life by at least five years.

Since the shuttle Atlantis' engagement with Hubble on Wednesday, the seven-member crew has achieved six of their ambitious mission's highest priorities.

The new science instrument, the Cosmic Origins Spectrograph, was developed to study the grand scale structure of the universe to explain how galaxies formed and clustered.

NASA plans for it chart the chemical evolution of the universe and in particular the stellar production of carbon and the other elements necessary for life.

The Advanced Camera for Surveys increased Hubble's field of view and observing efficiency 10-fold when it was installed in 2002.

However, an internal electrical short five years later shut down the imager's ability to observe distant galaxies, and cut short a promising future unraveling the mysteries of dark matter and dark energy.

The spacewalkers resurrected the camera in an intricate effort that involved opening up the device, replacing an internal electronics box, and attach a new power supply.

"This is the first time we have tried to repair an instrument like this in space," said David Leckrone, NASA's chief Hubble astronomer, on Saturday.

"It's a totally new enterprise, a repair in the sense of actually getting in to the guts of an instrument and changing out circuit boards.

"Anytime you try something brand new, when the stakes are high, that is a hold-your-breath time," he said.

The repair involved removing 32 tiny screws to access the camera's insides -- and using a specially designed cover plate in a bid to not let any of the critical parts float off into space.