Shuttle 4's secret debut.

Atlantis, fourth member of American's space shuttle fleet, made its debut Oct. 3 when it took off on only the second classified, military, manned space flight in the history of the U.S. space program. Four days later, after what was widely reported to be the deployment of two DSCS III communications satellites for the Defense Department, the craft landed safely at California's Edwards Air Force Base.

The satellites, said to be resistant to jamming and to the electromagnetic pulse (EMP) of nuclear blasts, are believed to have been deployed to geostationary orbit aopt a single rocket, from which they would then separate to their assigned positions.

Atlantis, lighter in weight than the three other shuttlecraft, has also been strenghened to handle the higher rocket thrust required for launchings to polar or near-polar orbits from the West Coast, where a Defense Department shuttle-launch facility is now being built at Vandenberg Air Force Base in California.