Final flight preps underway at KSC

The Virgin Atlantic GlobalFlyer is undergoing final flight preparations at the Kennedy Space Center's shuttle runway as adventurer Steve Fossett gears up for a dawn takeoff on what promises to be the longest flight in aviation history.

Now poised at the south end of the three-mile runway, the experimental aircraft is scheduled to take off to the north at 6:42 a.m. Tuesday.

Fossett will pilot the aircraft to a cruising altitude of 45,000 feet and then try to fly around the world and back across the Atlantic Ocean before landing at Kent International Airport east of London.

The 26,160-mile trip would be the longest nonstop flight in aviation history.

Fossett and financial backer Richard Branson, founder of Virgin Atlantic Airlines, inspected the GlobalFlyer on the shuttle runway Monday after holding a news conference with reporters and photographers from around the world.

The weather forecast for a takeoff Tuesday is marginal.

Temperatures at takeoff are expected to be 52 to 54 degrees Fahrenheit. The plane's single turbofan engine requires cold dense air to achieve full thrust at takeoff. Temperatures must be 54 degrees or lower as a result.

Winds are expected to be from the southwest at 11.5 mph to 18.5 mph, providing a good tailwind at takeoff. Global jet streams also are expected to be favorable.