Richard Abruzzo and Carol Rymer Davis were participating in the 54th Gordon Bennett Gas Balloon Race, an annual race in which teams of balloonists try to see who can fly the farthest from a set point on a maximum of about 35,300 cubic feet of gas.
Abruzzo is the son of famed balloonist Ben Abruzzo, who was in 1981 part of the first team to cross the Pacific Ocean by balloon, and who was killed in a small airplane crash in 1985.
Italian coast guards said a search was under way for the balloon, one of 20 that set off Saturday from the English coastal city of Bristol. Spokesman Lt. Massimo Maccheroni, said the last signal received from the balloon's GPS was at 8 a.m. local time Wednesday. The signal showed the craft was 13 miles off the Gargano coast in the Adriatic Sea.
He said helicopters, military aircraft and three boats were taking part in the search. A ground search on the coast also was under way.
Conditions in the area were reported to be poor, with rough seas and thunderstorms.
Abruzzo and Davis have competed together in the past, finishing third in the 2006 America's Challenge gas balloon race by traveling 1,478 miles from the Albuquerque International Balloon Fiesta.
Davis is a radiologist from Colorado who has previously participated in the race, her medical office said Wednesday. In a 2007 interview with Denver Woman magazine, she recalled competing in a race in 2004 alongside Abruzzo.
"We raced through six hours of drenching heavy rain - it was like the tropics. It poured into the basket. We were just soaked. It was heavy enough that it formed a little lake in the top of the balloon, so we pulled the valve and it would drench us," she told the magazine.
Richard Abruzzo's sister-in-law, Sandra Abruzzo, of Albuquerque, New Mexico, said she had been told the balloonists had suffered "an issue with the electrical" components in the balloon, and speculated that the loss of contact could possibly be related to that.
Garth Sonnenberg, also of Albuquerque and a friend of Abruzzo's since childhood, said he'd heard they had radio issues throughout the flight. "We're hoping that it's a good possibility that it's just a radio problem," he said.
Friends said that ballooning is in Abruzzo's blood. His father and two other Albuquerque residents, Maxie Anderson and Larry Newman, made the first successful balloon flight over the Atlantic in a helium-filled balloon in 1978, landing in France after a flight of 137 hours.
Former New Mexico Gov. Gary Johnson, who has flown with Abruzzo in several balloon races, said he was worried. He said Abruzzo always carried satellite phones when Johnson flew with him, and should not have lost contact.
Johnson said Abruzzo borrowed his high-altitude suit for the Gordon Bennett flight, and told Johnson he'd be back in plenty of time for him and Johnson to compete in the America's Challenge gas balloon race, which is scheduled to launch from Albuquerque on Tuesday.