A quarter of the way to history, millionaire adventurer Steve Fossett raced across North Africa on Tuesday in his bid to become the first person to fly a plane around the globe solo, nonstop and without refueling.

Fossett was about to cross into Saudi Arabia at nearly 47,500 feet just after 5 p.m. CST; he was traveling east at 360 mph, aided by a strong jetstream.

“I am covering territory fast, which is encouraging,” he said from the cockpit Tuesday afternoon. “It’s a long trip, especially at night. I feel a little bit tired, but I have been through it before.”

His experimental single-engine GlobalFlyer had consumed 25 percent of its 18,000 pounds of fuel, while Fossett had downed at least three diet chocolate milkshakes.

Fossett’s mission control in Salina estimated he will complete the 23,000-mile journey at midday Thursday.

Project manager Paul Moore said Fossett reached his cruising altitude of 45,000 feet over the Atlantic instead of over Saudi Arabia, as originally expected, because of better-than-expected performance of the GlobalFlyer.

Moore said Fossett planned to climb eventually to 49,000 feet.

For a while early Tuesday, Fossett was flying blind and in the dark over the U.S.-Canada border after experiencing difficulties with his global positioning system. Moore said Fossett relied on help from mission control to navigate before the problem corrected itself.

“It was a minor scare that could have been a real show-stopper,” Moore said.

Steve Fossett's Virgin Atlantic GlobalFlyer passes over the Atlas Mountains of Morocco. Fossett, who is attempting the first solo nonstop flight around the world, had finished about one-fourth of the total flight Tuesday.

The problem continued over Africa, Fossett said, with the GPS system sputtering but still functioning.

Will Whitehorn, a Virgin executive, was part of an airborne chase team that met up with Fossett on Tuesday as he approached Africa. The chase team will rejoin Fossett over the Red Sea.

“It was a fantastic scene off the coast of Morocco. It looked like a swallow against the mountains,” Whitehorn said. “No other aircraft I’ve seen looks quite like it.”