Michael Pease, 13, and his brother Tony, 10, of Kensington, took top honors in a model rocket contest yesterday, outlasting the competition in the "streamer duration" category. Michael's 6-foot mylar streamer kept his rocket in space the longest, but at that, it was all over in 16 seconds. Tony clocked in at 14.

The brothers were among about 100 participants and 1,400 observers at the NASA/Goddard Visitor Center in Greenbelt, who bypassed the space museum's air conditioning to squint into the sun, applauding the rockets' heights and blossoming parachutes and chuckling over the occasional dud.

The event marked the 14th anniversary of the Apollo moon landing and the 25th anniversary of NASA. Officially it was held "to promote interest in space-related activities," but the hobbyists were already hooked. Most spend up to $10 on prefab kits, available at hobby and toy stores, and log many hours patching together colorful variations on standard models.

Some models thundered away from the launching pads, destined for tough landings in the parking lot or in rocket-eating trees. Others sizzled skyward for hundreds of feet with a puff of smoke that smelled like fireworks. In fact, the black powder is the same, but hard-core hobbyists disdain the comparison, stressing the safety of their sport.

"There have been 100 million model rocket launches since 1958 and less than one one-hundredth of 1 percent of them malfunctioned," Goddard Visitor Center manager Ed Pearson told the crowd.

Leonard David, 36, of the National Space Institute (which cosponsored the contest with the American Institute of Aeronautics and Astronautics, and the NASA/Goddard Visitor Center), said he began building model rockets as a kid. "I'm still just a kid. That's why I'm here."

David suggested the sport offers "an understanding of center of gravity, propulsion, and aerodynamic principles." But mainly, he said, "the smell of rocket fumes is driving me to start again."

The wind confounded competitors in the spot landing event, where the goal was to land rockets as close to a marker as possible. "The smart rocketeer will aim at a 45-degree angle and use a small streamer so it comes down quickly," confided Craig Beyers, president of the Annapolis Association of Rocketry.

Most were wide of their mark. But Jeff Leef, 11, and his father watched their 20 hours of work climax in a few seconds, landing their rocket 28 feet from the target. "Last year I was disqualified. I shot the engine," Jeff Leef said, explaining that it popped out the top of the rocket's tube. "This year I put a piece of masking tape around the engine to make it fit tighter."

Afterward, astronaut Don Peterson, a spacewalker on the sixth shuttle flight, presented trophies to the winners. "I got into being an astronaut through science fiction," Peterson said earlier. "These kids are getting more direct exposure." Pressing Peterson for autographs, several of them said they wanted to be astronauts when they grow up.

The winners were Mark Newbern, 6 1/2, of Clinton, Md., in the junior (under 15) target proximity event, coming within 32 feet of the marker; Pierron R. Leef Jr., 39, of Kensington, with his son Jeff as designer, in the senior target proximity category; Michael Kraft, 16, of Stevensville, Md., in the senior duration event and Michael Pease as the longest-flying in the junior category.