Pilot Steve Fossett passed the halfway mark in his effort to break a long-distance flight record early Friday and began the long trip across the Pacific Ocean.
Mission controllers said that they were still concerned about winds and fuel, but that the high temperatures Fossett endured for the first 24 hours of the journey had abated.
It will take Fossett more than 16 hours to cross the Pacific in his Virgin Atlantic GlobalFlyer plane. His support team said in a statement posted on the that the winds across the Pacific looked good, but "the winds over the Atlantic are looking weak."
Fossett has already crossed the Atlantic once, shortly after taking off Wednesday from Cape Canaveral, Fla. But in order to break the nearly 25,000-mile (40,000-kilometer) record for the world’s longest aircraft flight, Fossett will need to cross it a second time. The GlobalFlyer's flight plan calls for a landing Saturday in Manston, England.
"The winds over the Atlantic will be crucial, and the team at Mission Control is working round the clock analyzing the movements of the jet streams," flight engineer Jon Karkow said in the statement. "Steve will continue to search out the best winds; even the smallest increase in speed will bring the record closer."
Mission controllers also said they were working out a new route for Fossett to fly between the specific predetermined way points he needs to reach for the record to be official.
Fuel is a concern because the GlobalFlyer lost 750 pounds (340 kilograms) during a from the Kennedy Space Center on Wednesday. The plane originally was calculated to finish the record-setting run with between 500 and 1,000 pounds (225 to 450 kilograms) of fuel remaining.
Another concern had been the soaring temperatures in the cockpit, which had required Fossett to drink a large amount of his water supplies. A malfunction in the ventilation cooling system at times caused the temperature to reach 130 degrees Fahrenheit (54 degrees Celsius), Mission Control said.
But as the GlobalFlyer continues to burn fuel, the plane is getting lighter. This means the engine does not have to work so hard, which lowers the temperature in the cockpit. Mission Control said Fossett was now more comfortable, with temperatures around 60 degrees F (16 degrees C).
Fuel leaks plagued Fossett’s successful venture last year to become the first person to fly solo, nonstop around the world without refueling, and delayed his takeoff this week. Mission managers hadn’t pinpointed the cause of Wednesday's fuel leak but believed a buildup of pressure in the tanks may have been partly responsible.
Fossett is taking power naps no longer than five minutes each and drinking nutrition shakes while in the air. His plane is equipped with a parachute pack holding a one-man raft and a satellite rescue beacon, just in case.
The 80-hour, nearly 27,000-mile (43,470-kilometer) voyage would break the airplane distance record of 24,987 miles (40,212 kilometers) set in 1986 by the lightweight Voyager aircraft piloted by Dick Rutan and Jeanna Yeager, as well as the balloon record of 25,361 miles (40,815 kilometers) set by the Breitling Orbiter 3 in 1999.
The GlobalFlyer, which like the Voyager was designed by Burt Rutan, is made of lightweight carbon fiber and has a super fuel-efficient turbofan jet engine with a very high thrust-to-weight ratio.
Fossett in 2002 became the first person to fly solo around the globe in a balloon, and last March he became the first person to circle the Earth solo in a plane without stopping or refueling. That flight, also made in the Virgin Atlantic GlobalFlyer, lasted 67 hours.
Both that venture and the latest flight were financed by Virgin Atlantic Airways founder Richard Branson.