NASA Shortens Spacewalk For Shuttle's Earth Return

HOUSTON -- Two spacewalking astronauts helped prepare the International Space Station (ISS) for future shuttle missions Saturday, though NASA shortened their orbital work as Hurricane Dean edged closer to the Gulf Coast.

Astronauts Dave Williams and Clayton Anderson ended their spacewalk early to help prepare the space shuttle Endeavour for a possible Tuesday landing -- one day earlier than planned -- should Hurricane Dean threaten NASA's Mission Control center here at the Johnson Space Center (JSC).

"Whoo man, you can't miss that," Williams said as the ISS passed 214 miles (344 kilometers) above Dean during the five-hour and two-minute spacewalk. "That's impressive."

"It's only impressive when they're not coming to you," said Anderson, an ISS flight engineer, said of the storm.

As of early Saturday, Hurricane Dean was a category four storm and growing, with maximum wind speeds of 150 miles per hour (240 kph) as it heads toward the Mexico's Yucatan Peninsula.

Spacewalkers were initially scheduled spend about 6.5 hours installing a shuttle inspection boom stand and other equipment outside the ISS. But NASA scaled back the work due to Hurricane Dean's approach to the Gulf Coast, where it may impact coastal Texas early next week.

Storm preparations

NASA is drawing up plans to shift its shuttle Mission Control operations in Houston to a backup site at the Kennedy Space Center in Cape Canaveral, Florida should the storm force an evacuation at JSC and its surrounding area. Space station Mission Control would transfer to Russia's Federal Space Agency operations center outside Moscow.

Endeavour is currently slated to land on Wednesday, but its STS-118 astronaut crew is expected to shut hatches between the orbiter and space station at about 5:01 p.m. EDT (2101 GMT) today in preparation of a possible Tuesday Earth return.

Astronauts aboard Endeavour and the ISS worked today to complete hauling supplies and equipment between their two spacecraft to clear the way for tonight's hatch closure. Teacher-turned-astronaut Barbara Morgan, who served as NASA's backup for Teacher in Space Christa McAuliffe for the ill-fated 1986 Challenger launch, is overseeing the cargo transfer.

NASA mission managers are expected to decide later today whether to allow Endeavour to remain at the ISS until Monday as planned or press ahead with an earlier departure on Sunday for a Tuesday landing.

Hurricane Dean is the latest worry for NASA after shuttle mission managers cleared concerns over a deep divot in Endeavour's heat shield on Thursday.

Shortened spacewalk

Williams and Anderson began their spacewalk at 9:17 a.m. EDT (1317 GMT) to install a shuttle inspection boom stand atop the station's Starboard 1 truss and tighten a series of stubborn bolts to secure an antenna mount into place.

The antenna mount is due to return to Earth during an October shuttle flight. Meanwhile, astronauts plan to store a shuttle inspection boom at the ISS during a February mission to await another orbiter crew.

The two spacewalkers took care to avoid any regions with sharp edges outside the ISS and checked their spacesuit gloves frequently for any signs of wear or damage. The added measures came after their fellow crewmate Rick Mastracchio found a small hole through two of the five layers of his own spacesuit glove on Aug. 15, cutting his spacewalk short.

"My gloves look like they just came off the showroom floor," Anderson said after the spacewalk.

Williams and Anderson also attached a wireless sensor system antenna outside the ISS and retrieved a pair of suitcase-like material exposure experiments, but left some misaligned debris shields for later astronauts to wrangle into place.

A fire alarm sounded inside the space station's Unity connecting node during the spacewalk, but the orbital laboratory's crew found no signs of smoke and Mission Control deemed it a false alarm.

Saturday's spacewalk marked the third for Anderson, who now has a total of 18 hours and 11 minutes of orbital work under his belt.

Williams, a veteran Canadian Space Agency astronaut, set a new national record during the activity to become Canada's first spaceflyer to perform three spacewalks for a total time of 17 hours and 47 minutes during his STS-118 excursions.

"It's a real honor and pleasure to do it," Williams said.

The spacewalk was the fourth and last planned for Endeavour's crew, which spent a total of 23 hours and 15 minutes working outside the ISS. It also marked the 92nd dedicated to ISS assembly or maintenance and the 64th staged from the orbital laboratory itself.

NASA is broadcasting Endeavour's STS-118 mission live on NASA TV. Click here for mission updates and SPACE.com's NASA TV feed.

• VIDEO: STS-116 Mission Profile: Fourth Spacewalk
• VIDEO: Endeavour Shuttle Tile Damage
• Complete Space Shuttle Mission Coverage

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