SPACE CENTER, Houston (AP) _ A half-ton metal satellite and its 12-mile leash snaked through orbit free of shuttle Columbia today after breaking loose without warning and drifting into space.

The electricity-generating experiment ended abruptly Sunday night, five hours after it began, with an urgent message from astronaut Jeffrey Hoffman.

``The tether has broken at the boom! The tether has broken! It is going away from us!'' he told Mission Control.

Ground controllers verified after a few anxious moments that the satellite and its 12.2 miles of dangling cord, resembling a long, spiraling french fry, posed no danger to the seven astronauts.

Although relieved the crew was safe, American and Italian researchers who had poured years into the tethered satellite system were crushed.

``There is ... intense disappointment,'' NASA mission scientist Nobie Stone said today.

No evasive action was needed by the shuttle pilots. The satellite and tether were more than 18 miles away from Columbia within minutes after the break and hundreds of miles away within hours. The satellite eventually will burn up in the Earth's atmosphere.

The slender cord, one-tenth of an inch thick and resembling a boot lace, was supposed to be unreeled to a distance of 12.8 miles. It was nearly to that point when the break occurred inside a 40-foot tower in the shuttle cargo bay.

If the cord had snapped higher up, the portion remaining attached to Columbia might have gone out of control and possibly even wrapped around the shuttle.

Astronauts later said the tether appeared frayed and stripped and noted that its nylon and Teflon outer coating looked to be charred and melted. The satellite and cord were generating about 3,500 volts of electricity as they swept through Earth's magnetic field.

NASA officials refused to speculate on what might have gone wrong but promised to find out. All data was ordered impounded. The shuttle is due to return March 7.

``Everything is a suspect at this point,'' said lead flight director Chuck Shaw. ``That's the reason the effort is to don't disturb the crime scene until you're sure that you've collected all the information.''

It was the second voyage of the $443 million U.S.-Italian experiment. Both ended with trouble. In 1992, the tether jammed when the satellite was only 840 feet out.

Stone said this flight was more disappointing because scientists were so close to seeing what the satellite-tether system can do.

``I have a black lab at home, and if you take a piece of meat and you go by real fast and you get his attention ... he really hasn't realized what he's missed yet,'' Stone said.

``If you hold it in front of him, he begins to drool all over the place because he has some anticipation. In this sense, this is a little worse.''

The satellite was to have flown free of the shuttle for two days before astronauts reeled it back in. Scientists hoped to prove that such a system could be used to power spaceships or drop packages from space to Earth.

The satellite, a white metal ball 5 feet in diameter, was propelled by small thrusters from a tower in the shuttle cargo bay Sunday afternoon. The tether, threaded through the tower, was attached to a giant spool.

There were a few surprises as the tether unwound through the day, but nothing serious, and everything seemed to be going well. That's why officials were so puzzled when the tether broke.

While the astronauts planned to move on today with crystal, metal and fire experiments, they couldn't help thinking philosophically about the one that got away.

``Nobody said it was going to be easy,'' Hoffman said.

Added Shaw: ``If you don't ever get your nose bloodied, you're not in the game. We got our nose bloodied this time.''