The next flight of the space shuttle Columbia will carry two giant communications satellites into orbit and the most astronauts ever to fly in one spacecraft at the same time.

The satellites to be carried aloft in Columbia's cargo bay Nov. 11 will be 10 feet tall and 5 feet wide and weigh 5,000 pounds each.

One belongs to Satellite Business Systems, and will be deployed from the shuttle over the Pacific Ocean between Hawaii and Chile, then boosted into a higher orbit. The other, named Telesat, is owned by Canada, and will be deployed in the same place the day after the SBS satellite.

"It is a four-man operation to launch those satellites," astronaut Robert F. Overmeyer, the crew-cut Marine colonel who will copilot the next shuttle flight, said yesterday at the Johnson Space Center in Houston. "We'll be launching them when we're out of radio communications with the Earth, and we'll need all four people aboard to handle it."

Overmeyer will be copilot for Vance D. Brand, a veteran astronaut who will command the four-day mission and who flew on the Apollo-Soyuz flight in 1975. Like Overmeyer, the other two crew members, Joseph P. Allen and William B. Lenoir, will be making their first space flight. Both are physicists with Ph.D. degrees.

To handle four astronauts, the shuttle's two ejection seats will be removed and replaced with three cockpit seats that cannot be used as ejection seats.

The fourth crew member will ride in a new seat to be installed in the mid deck of Columbia's cabin, just outside the airlock that Allen and Lenoir may use to enter the cargo bay for the first shuttle space walk.

None of the astronauts seemed bothered by the fact that they will be the first to fly the shuttle without being able to eject if the spaceliner is damaged during liftoff.