A U.S. spy satellite that was reported to have broken apart in space shortly after its March launch aboard the shuttle Atlantis has been spotted in orbit 503 miles up by amateur astronomers.

The Soviet news agency Novosti reported March 7 that four fragments observed in orbit had "presumably separated from the American spy satellite," which apparently "has been blown up by its owners for some unknown reasons."

The U.S. Defense Department acknowledged at the time that segments "associated with" the payload were reentering Earth's atmosphere and burning up. The Pentagon insisted, however, that the Atlantis mission "achieved its goal," and some experts at the time suggested that the falling pieces were coverings deliberately separated from the craft.

The satellite has been observed independently by astronomers in Canada, Scotland and France, according to Ted Molczan of Toronto, who collects reports from other amateur observers. They pooled their measurements and used a process of elimination to tie it to the Atlantis launch.

The astronomers apparently did not detect it sooner because it appears to have boosted itself to a higher orbit and a different angle -- 65 degrees relative to the equator -- from Atlantis's planned path, Molczan said.