NASA Clears Space Shuttle Discovery for Landing

by Tariq Malik, Senior Editor

Date: 13 June 2008 Time: 05:50 PM ET

Space Shuttle Crew Prepares for Saturday Landing

A view of the Shuttle Discovery soon after the shuttle and the International Space Station began their post-undocking relative separation on June 11, 2008. One of the Expedition 17 crewmembers recorded the photo with a digital still camera.
CREDIT: NASA.

CAPE CANAVERAL, Fla. - NASA mission managers cleared the shuttle Discovery for a weekend landing Friday after swiftly settling concerns with a lost metal clip that drifted away from the spacecraft earlier in the day.

Commanded by veteran spaceflyer Mark Kelly, the shuttle is on track to land on a runway here at NASA?s Kennedy Space Center at 11:15 a.m. EDT (1515 GMT) on Saturday.

?We have a very healthy crew, a very healthy vehicle,? said NASA entry flight director Richard Jones.

Discovery?s seven-astronaut crew is wrapping up a two-week mission to the International Space Station, where they delivered a new crewmember, spare parts for a Russian toilet and installed Japan?s $1 billion Kibo laboratory. They also performed three spacewalks and attached a storage room atop the new Kibo lab during the flight.

Engineers, today, gave Discovery?s heat shield a clean bill of health based on imagery and data from Wednesday scan by the crew using the shuttle?s sensor-tipped inspection pole.

But it was early today that Kelly and his crew spotted a shiny, rectangular piece of metal drifting away from the shuttle?s aft after pushing Discovery through a standard - but rigorous - set of thruster and flight control surface exercises.

?It?s a fairly dynamic activity in the aft part of the vehicle,? said LeRoy Cain, NASA?s deputy shuttle program manager. Debris after spotted after similar pre-landing checks aboard the shuttle Atlantis in 2006 led to one-day mission extension for extra heat shield inspections.

Discovery mission specialist Michael Fossum quickly snapped video and photographs of the object, which engineers later identified as a small metal clip used to bridge heat-resistant insulation on the shuttle?s tail during liftoff. Similar clips have fallen off orbiters in past missions and their loss poses no threat to the orbiter?s landing.

While Kelly initially estimated it could be up to 1 1/2 feet (0.4 meters) long due to lack of reference, the V-shaped tab was about 2 1/2 inches by 1 inch (6 cm by 2 cm), Cain said. Mission managers are now considering having astronauts stand by with cameras during future checks to quickly rule out similar debris, he added.

In a televised interview today, Kelly said he was initially concerned over the debris when it was an unknown object, but had no worries once it was identified.

?We were impressed at how quickly [and] the quality of work they were able to do,? Kelly said.

A protruding bit of material on the tail rudder also reported by the astronauts was actually part of the shuttle?s thermal barrier and of no concern, Cain said.

Discovery has two opportunities to land at the Kennedy Space Center tomorrow, though there is a slight chance of nearby rain showers for the second approach at 12:50 p.m. EDT (1650 GMT). The shuttle launched May 31 and is NASA?s third orbiter to fly this year.

The shuttle has enough supplies to remain in space until Tuesday, allowing mission managers more freedom in targeting its primary landing site here in Florida. Should foul weather thwart a Florida return, NASA would activate an alternate landing site at California?s Edwards Air Force Base, where the orbiter would have to make use of a new, shorter runway due to ongoing construction.

But Jones said the weather in Florida through Monday is encouraging for Discovery?s return to the Kennedy Space Center.

?We?re looking forward to a successful landing tomorrow,? Jones said.

NASA is broadcasting the Discovery's STS-124 mission live on NASA TV. Click here for SPACE.com's shuttle mission updates and NASA TV feed.