LOS ANGELES -- As the clock struck midnight on Wednesday, a $250,000 prize to the first private group to launch a rocket into space expired, unclaimed.

The challenge of the Cheap Access To Space (CATS) prize: launch a 4.4-pound (2-kilogram) payload to a height of at least 124 miles (200 kilometers). No "substantial" use of government-derived designs or surplus hardware was allowed under contest guidelines.

Back in November 1997, when the prize was announced, contest administrators demanded 30-days' notice of any launch attempt. The 15 or so teams then in contention bristled at the rule, claiming it would hinder their efforts. Now, a full three years later, only two teams ever mustered serious attempts to snag the prize.

Neither was successful.

"Nobody won it. Thats it. Todays the final day," said James George, of the Space Frontier Foundation, on Wednesday.

The group, along with the Foundation for the International Non-governmental Development of Space, saw the contest as a way of promoting private sector activity in space -- much as the more ambitious X-PRIZE is doing on the human side of rocketry.

Most recently, the High Altitude Research Corp. launched a rocket from a balloon-borne gondola sent aloft from the Gulf of Mexico in what was generally agreed to be the last stab at the CATS prize. The rocket ignited, but failed to reach an altitude of more than 15 miles (24 kilometers) during the October 29 attempt.

Earlier, JP Aerospace had hoped to gun for the $50,000 consolation prize by sending a rocket to 74 miles (120 kilometers), an attempt that was scotched by a last-minute bureaucratic "nyet" -- or at least a launch-delaying "not yet" -- from the Federal Aviation Administration.

David Anderman, who wrote the CATS prize rules, said the contest wasnt all a wash, even if the deadline came and went without a winner.

"Had we not had a deadline Id suspect we wouldnt have had any launches," Anderman said. "The teams did not come as far as we thought when we established the prize, but they did make demonstrable progress."