Discovery mission crowned with success for Hubble

Discovery mission crowned with success for Hubble
AGENCE FRANCE PRESSE

HOUSTON, DEC 25: The Discovery space shuttle's Christmas mission to repair the crippled Hubble space telescope was declared a complete success late Friday as two US astronauts completed a third and final space walk and returned to the shuttle.

"Full mission success," announced Steve Robinson at the mission control center here after tests carried out from the earth revealed that all the new equipment installed on board the Hubble telescope was in perfect working order. "We'd like to congratulate all of you," Robinson said in a message to the seven astronauts aboard Discovery, which blasted off on Sunday on an eight-day mission to repair the telescope. Steve Smith and John Grunsfeld, both of the United States, completed the third and final space walk late Friday after eight hours and eight minutes in space. An exhausted Steve Smith, speaking after the two had returned to the shuttle, described the Hubble as the "world's greatest telescope," adding that the team "hope to see it back in service very soon."

"We would also like to wish everybody happy holidays and some peace on Earth," Smith added. The 12-tonne, four-storey high telescope had been out of Commission since November. The two astronauts' key task Friday had been to replace a radio transmitter that had stopped functioning recently one of the Hubble's two "S-Band Single Access Transmitters" that transmit data on the universe back to Earth via NASA communications satellites in orbit some 33,000 kilometers (54,000 miles) off Earth. Grunsfeld, who was unable to get into his own suit and had to borrow fellow astronaut Michael Foale's outfit, mounted the end of the Discovery's 15-meter (50-foot) robotic arm. From there, he was working with Smith, who was attached by a security line to the telescope. The pair also installed a second digital, magnetic solid-state recorder, alongside one installed in 1997 and replacing an analog recorder. The new one will be able to store ten times as much data as the old one. Once the electronic chores were done, the twoastronauts began work on installing new thermal protective covers on the Hubble. Thermal protection is critical for the Hubble, since one side of it faces the Sun continually, cooling when it goes behind the Earth from a steamy 80 degrees Celsius (175 degrees Fahrenheit) to a frigid negative 54 (negative 67) a range of more than 130 (240) degrees.

This oscillation in temperature occurs 16 Times a day the Hubble completes its path around Earth once every 97 minutes and has been doing so for 10 years. Both its outer protection and the radiators inside function to keep its interior temperature relatively steady. On the last two space walks, Wednesday and Thursday, Discovery replaced the Hubble's six gyroscopes, its central computer and its precision guidance detector. This "extremely successful" repair mission should give the giant telescope "another decade of life," says David Leckrone, the Hubble program's senior scientist at the Goddard space center in Greenbelt, Maryland.