Atlantis' five astronauts, orbiting Earth in a public silence imposed by the Pentagon, deployed a spy satellite aimed at Iraq and will return to Earth on Monday, NASA and military sources said Friday.

The astronauts spent their first full day in space Friday working under a shroud of secrecy. However, sources speaking on condition of anonymity said the satellite was placed in orbit.NASA punctuated the silence Friday evening to report that Atlantis would land at Edwards Air Force Base, Calif., sometime between 5 p.m. and 8 p.m. EST Monday. A more precise time will be announced 24 hours before landing.

"The crew is doing well, and the orbiter Atlantis continues to perform satisfactorily," said Mission Control's Kari Fluegel.

Atlantis thundered into orbit Thursday night carrying a satellite that purportedly is to spy on Iraq. The shuttle was visible along the entire Florida coast and as far north as South Carolina as it rode a 700-foot column of flame through the darkness.

It was the fifth time NASA launched a shuttle at nighttime and the seventh and last time a shuttle will carry a classified military cargo into space.

Atlantis' crew, commanded by Air Force Col. Richard Covey, had been expected to release the spy satellite from the shuttle's cargo bay within 24 hours of liftoff. Experts believe the spacecraft will focus cameras or electronic signal detectors on the Persian Gulf.

The Pentagon plans to use the shuttle two more times, both in 1991 to carry unclassified cargoes. Future military satellites will be lifted into orbit by unmanned rockets, principally the Titan 4.