Shuttle astronauts gear up for Friday landing

Astronauts on the shuttle Atlantis faced a stormy weather outlook as they began preparations Thursday to bring a successful mission to overhaul the Hubble Space Telescope to an end.

There were landing opportunities at NASA's Kennedy Space Center in Florida on Friday at 1400 GMT and 1539 GMT.

On Wednesday, mission managers instructed the shuttle's seven astronauts to conserve electricity by turning off unneeded computers and other equipment in case thunderstorms and gusty winds forced them to wave off. Atlantis carries provisions to remain in orbit through Monday, if necessary, said NASA's LeRoy Cain, who chairs the management team.

Early Thursday, Atlantis commander Scott Altman and his crew conducted successful tests of the shuttle's steering thrusters and hydraulic systems, the equipment that will guide them back to Earth.

They were also scheduled to make an appearance by satellite television before the Senate Commerce, Justice and Science appropriations subcommittee chaired by Senator Barbara Mikulski of Maryland. Maryland is home to NASA's Goddard Space Flight Center, the ground control facility for Hubble, as well as the Space Telescope Science Institute.

The lawmakers intend to discuss NASA's budget.

Late Wednesday, the Atlantis astronauts earned praise from President Barack Obama for their efforts to extended observations with the 19-year-old space telescope by at least five years.

"I'm hoping you guys recognize how important your mission is to the world as well as to this country," the president told the Atlantis crew in a six minute telephone exchange from the White House.

"I can assure you it's a high priority of mine to restore that sense of wonder that space can provide and to make sure we have a strong sense of mission, not just within NASA but for the country as a whole," Obama said.

The shuttle astronauts lifted off on May 11. They rendezvoused with Hubble two days later, using the shuttle's robot arm to haul the telescope into the cargo bay. The observatory was released on Wednesday following five obstacle-filled spacewalks that added two new science science instruments, a science computer as well as gyroscopes and batteries to fortify the precision pointing and power systems.

A camera and spectrograph sidelined for several years by internal electrical problems were repaired as well.

The enhancements have equipped Hubble to search for the earliest galaxies, probe the mysteries of dark matter and dark energy as well as study the planet making processes under way around other stars, according to astronomers.