The pilots of a helium-filled balloon flying across the Pacific Ocean surpassed a duration record Friday by spending more than 138 hours in the air, marking a historic day for the team that already has eclipsed a distance milestone as they approach North America.
Pilots Troy Bradley of Albuquerque and Leonid Tiukhtyaev of Russia were headed south along the California coast when they surpassed the duration record of 137 hours, 5 minutes and 50 seconds aloft in a traditional gas balloon.
Bradley Tweeted the following images from the team's Twitter account:
The pair launched from Saga, Japan, shortly before 6:30 a.m. Sunday Japan time, eclipsed the distance record of 5,209 miles Thursday and are expected to land in Mexico early Saturday.
The duration milestone is considered the "holy grail" of ballooning. It was set in 1978 when Ben Abruzzo, Maxie Anderson and Larry Newman made the first trans-Atlantic balloon flight.
To establish a record, international aviation rules required Bradley and Tiukhtyaev to stay aloft 1 percent longer than the currentrecord. The distance and time still have to be confirmed by the Federation Aeronautique Internationale, a process that can take weeks or even months.
When the duration mark was reached, mission control team members cheered and held up their smartphones to document the moment, much as they did Thursday when the distance record was bested.
Mission control director Steve Shope said the focus is getting the balloon the rest of the way across the Pacific to a safe landing. No one has crossed the Pacific in a gas balloon since 1981.
"Maybe later when they get down on the ground, I can look back and say this is a great accomplishment, but right now we have a big job ahead of us to get this balloon down," Shope said.
The plan is for the balloon to continue south toward Baja California, Mexico, where the pilots plan to skim the water Saturday before touching down on the beach. Once the pilots reach the sand, they would have traveled an estimated 6,835 miles.
A chase crew of volunteers and members of the mission were en route Friday.
The team originally planned to cross into North America in Canada but shifted the plans because of changing weather. They are now catching a wind pattern that will take them south.
The shift was tough on the pilots, who have been on oxygen for days and in high altitude that can take a physical toll, Shope said.
"It's a pretty sophisticated dance up there," said Ray Bair, a member of the mission control team.
The balloon is outfitted with an array of monitors and other instruments that are tracking its course and compiling data to be submitted to the record-keepers. With a massive, helium-filled envelope and a specially-designed carbon fiber-composite capsule, it was designed to stay aloft for up to 10 days, but the loss of gas and ballast has shortened that time by a couple of days.