The countdown for the first space flight to include crew members and satellites from several nations continued smoothly yesterday, with launch of the shuttle Discovery set for this morning at Cape Canaveral in Florida.

Barring a last-minute glitch or unforeseen weather delay, the spacecraft is set to lift off from Kennedy Space Center at 7:33 a.m. on a seven-day flight, the 18th shuttle mission in just over four years.

"We're ready to go, everything is running smoothly," NASA Associate Administrator Jesse W. Moore said at a briefing yesterday.

After five straight days of rain, Florida's weather began to cooperate, and the forecast looked good for an on-time launch.

"We expect some patchy ground fog but no rain," said Air Force Lt. Scott Funk, chief shuttle weather officer. "We're calling for scattered clouds up to 5,000 feet and broken clouds at 25,000 feet, but nothing that will put a damper on launch."

Discovery's seven crew members include French Air Force Col. Patrick Baudry and Saudi Arabian Prince Sultan Sulman Al-Saud, 28, a nephew of Saudi King Fahd.

"You will have 800 million Moslems glued to their television sets watching an American spaceship carry an Arab into space," Al-Saud said recently. "I feel very proud to represent 22 Arab nations of the world on this flight."

In Discovery's cargo bay will be communications satellites owned by Mexico, an Arab consortium called Arabsat and telephone giant American Telephone & Telegraph Co. Also in the bay will be three scientific experiments financed by West Germany.

The flight will have a "Star Wars" element. Discovery's crew is to position a mirror in a window to reflect a ground-based laser beam to an Air Force base on the Hawaiian island of Maui. The test, the first of many "Star Wars" experiments planned for the space shuttle, is intended to determine whether laser beams can hit orbiting mirrors in space to deflect their beams toward another satellite.

The crew is also to deploy a satellite called Spartan and maneuver it to about 60 miles away from the shuttle, where it will take X-ray photographs of distant stars in the Milky Way galaxy. Two days later, the satellite will be retrieved for return to Earth, where its videotape film will be studied by scientists. The satellite cost $3.5 million, easily the cheapest satellite of its kind to be taken into space.

Also in the crew are Navy Capt. Daniel C. Brandenstein, Navy Cdr. John O. Creighton, Air Force Lt. Col. Steven R. Nagel, Air Force Col. John M. Fabian and Shannon W. Lucid, a scientist and the sixth American woman to go into space.