American Troy Bradley and Russian Leonid Tiukhtyaev have surpassed the world distance record for a flight in a helium balloon after crossing the Pacific Ocean.
The two pilots also hope to set a new duration record.
Troy Bradley and Leonid Tiukhtyaev left Japan in their “Two Eagles” balloon on January 25 and had aimed to land in Canada or the US.
However, weather has forced them to change course towards Mexico where they are due to land sometime on January 31.
Their hi-tech balloon is fitted with monitors and other instruments that track their course and compile data to be submitted to record-keepers.
The specially-designed capsule sits beneath a huge helium-filled envelope and is designed to stay aloft for up to 10 days.
To set new distance and durations records the team needed to beat the existing records by 1%.
Photo Tami Bradley
For distance that meant a journey of about 5,260 miles to beat the existing record of 5,208 miles set in 1981.
On January 29, the Two Eagles team tweeted: “The pilots have just surpassed the distance needed to set a new record. 5,261 miles or 8,467km.”
“We’re not taking any time to celebrate,” said head of mission control Steve Shope.
“We have a lot of work we have to do, and we’re just taking this flight one hour at a time.”
On its website, the team says Two Eagles will not have “broken the record” until documentation is approved by the US National Aeronautic Association followed by the Federation Aeronautique Internationale – a process that could take several weeks or months.
The existing duration record they hope to beat was set in 1978 when three pilots made the first trans-Atlantic balloon flight, spending 137 hours, 5 minutes and 50 seconds in a gas balloon.
To set a new record, the Two Eagles team must stay aloft for about 138 hours and 45 minutes.
At the moment, it is not clear exactly where the Two Eagles balloon will land.
The team had been aiming for Canada but a ride of high-pressure ridge off the US West Coast forced the balloon into a sweeping right turn toward Mexico.
A network of balloon enthusiasts has been organized to act as chase crews, but correspondents says it remains unclear if the balloon will be able to land in a place where a ground crew can help them.