He's just circled the globe solo in a balloon. Already he's scaled all but one of the tallest mountain peaks on every continent and raced dogs in the Iditarod. 

Now adventurer Steve Fossett has his sights on the stratosphere. 

Still high above the ocean, still hours from making landfall and still hours more from setting down his record-setting balloon, Fossett was asked, "What's next?" 

It's the obvious question for the American millionaire, who has raced cars at Le Mans and jets against the record book. 

"I don't want to talk too much since I'm not on the ground yet from this one," Fossett said Tuesday by satellite phone, minutes after becoming the first solo balloonist to circle the world. 

But, in his next breath, the same spirit that led the investment tycoon from Chicago to keep coming back to the circumnavigation record — despite repeated and sometimes spectacular failure in five previous attempts — took over. 

"My next big project is to fly a glider into the stratosphere, and we'll make the first attempt on that before the end of July," he said. 

If he pulls the glider flight off, Fossett will be adding to a lengthy and diverse resume of adventure. 

"This guy has done a lot of oddball things," said Joe Ritchie, Fossett's friend of more than three decades and chief of the St. Louis mission control center that helped guide Fossett's balloon around the world. 

Some of Fossett's past adventures don't come with records, including scaling the highest peaks on all but one continent, or skiing across Greenland. Other times, Fossett's standing has been well off the pace of the world's best, including a 47th-place showing in the 1992 Iditarod. 

But world records are kept in gliding by the Federation Aeronautique Internationale, the same Swiss-based organization that will certify that Fossett's balloon has indeed circled the globe. 

There are several federation gliding records Fossett can chase, but he'll have to beat 49,009 feet to claim the absolute altitude record in the open class, set 16 years ago by Robert Harris of California City, Calif. 

Within weeks, Fossett plans to take aim at the stratosphere and 60,000 feet, a flight that's part of a larger effort to design a glider that can reach heights of 100,000 feet or more. Getting it there will require help from NASA engineers and pressure suits borrowed from the U.S. Air Force and once used by SR-71 pilots. 

It's a feat that comes with enough risk — even for a guy who has both sailed and flown around the world alone — to worry Ritchie. 

"I'm going to watch from the cheap seats from here on out," Ritchie said. "I'm going to talk to him about this next thing he is doing, because it scares me, frankly." 

But unlike setting records in mainstream sports — on his way to hitting 73 home runs last year, Barry Bonds never faced a 29,000-foot plunge into the Coral Sea as Fossett did in his fourth solo balloon attempt — Fossett's record-setting always seems to entail an element of risk. 

To Ritchie, the ideas come from the crowd he hangs out with — sailors, mountain climbers and other adventurers. 

"That's a kind of community that dreams these things up that the rest of us just never think of," Ritchie said. "I think there is a little bit of, 'Can you top this?"'