A crystal experiment that survived five days in space aboard the shuttle Discovery was rendered useless when it was tipped over going through an airport X-ray machine.

"That's the way it goes in science," said Alexander McPherson, a University of California, Riverside biochemistry professor who sent the experiment into space. "I'm not real happy."The Los Angeles Times reported Sunday that the experiment, one of 60 crystal tests aboard the shuttle, was destroyed at the Birmingham, Ala., Municipal Airport one day after Discovery's March 18 landing.

McPherson's project was designed to learn how protein crystals grow in a weightless environment, something that could help scientists design new cancer-fighting drugs. Gravity makes it extremely difficult to grow perfect crystals on Earth.

McPherson's assistant, Stan Koszelak, flew to Birmingham to carry the experiment back to Riverside.

The experiment, which during the survived 79 orbits and a perfect landing, had been taken to the University of Alabama at Birmingham, where the crystals were unpacked and placed in glass plates.

The dishes were packed inside a Styrofoam ice chest and Koszelak was instructed to keep the chest upright. As he was going through the X-ray station, he warned security officers to keep the box upright while it passed through the machine, McPherson said.

"As it was coming out the other end it started to tip over . . . Stan let loose a scream," McPherson said. A well-meaning security guard turned the box upside down in trying to help, effectively destroying the experiment, McPherson said.

McPherson said officials of the National Aeronautics and Space Administration are aware of the incident.

"They were dismayed to say the least," he said. "NASA has stickers we could have put on the container that would have allowed us to carry it straight through without security examination. Someone never thought to do that."