The "cola wars" move off Earth into space today when the crew of the space shuttle Challenger takes the world's two largest-selling soft drinks into orbit for the first time.

Four high-tech cans of Pepsi-Cola and the new Coca-Cola, the first carbonated beverages ever flown into space, will be taste-tested by Challenger's seven-man crew. The two new pressurized cans took more than two years to test on Earth. Pepsi-Cola said its can cost its supplier, a company called Enviro-Spray, $14 million to develop.

The mission's more serious cargo includes the Spacelab, with five telescopes worth $80 million; the telescopes will be used in seven days of continuous observations of the sun and the stars impossible from Earth. Three of the telescopes will be aimed at the sun using an instrument pointing system built in Europe that is so precise it can lock on and track a dime two miles away.

"We're carrying some very sophisticated instruments on this flight and possibly the best telescopic aiming device ever built," Dr. Jeffrey D. Rosendahl, NASA's assistant associate administrator for space science, said yesterday at a prelaunch briefing at the Kennedy Space Center in Florida. "There's going to be some very good new science on this mission."

The 19th flight of the space shuttle, and the third flight of the European-built Spacelab, is scheduled for a rare afternoon liftoff from the center at 4:30 p.m. EDT, which is just about the time summer thunderstorms routinely hit Cape Canaveral. Launch directors have allowed themselves a launch "window" of more than two hours for this liftoff, meaning they can delay the flight until almost 7 p.m. if rain falls on the launch pad at 4:30.

"Fortunately, we've measured one-tenth of an inch of rain out on the launch pad in the last 10 days," Lt. Scott Funk, Air Force shuttle weather officer, said. "We're not in a typical weather pattern right now and any showers we get at launch time should be very brief and move rapidly out to sea."

The "good new science" Rosendahl mentioned took a back seat yesterday to the soft drinks riding into space, courtesy of the cola warriors.

"This new can is a precursor of containers to come that will use an alternate means of dispensing drinks on Earth," Pepsi-Cola Vice President Tom Williams said at the Johnson Space Center in Houston. "I'm thinking of 10-gallon refrigerator containers that will be too large for one person to hold in one hand. That is what this is. An alternate way of dispensing a beverage."

Until today's flight, space travelers have always been limited to water, fruit juices, coffee and tea. Carbonated drinks were not taken into space because the pressurized bottles and cans they came in were felt to be unsafe in the super-clean atmosphere of spacecraft cabins.

"These two dispensers have been well-tested here on Earth," Dr. Sam L. Pool, chief flight surgeon at the Johnson Space Center, said. "We like the idea that we can vary the beverage diet. It gets more fluid into the astronauts, who have experienced an average loss of 10 percent of their body fluids during a mission from dehydration."

Sitting behind exact replicas of the cans riding on Challenger, Pepsi-Cola's Williams and Coca-Cola scientist Ashis Gupta described two similar but differing technologies used to develop the new drink dispensers.

Pepsi-Cola fills a can with eight ounces of cola and a plastic pouch that expands when chemicals are mixed inside it to create carbon dioxide gas, which then inflates the pouch and forces the beverage out. Williams said the can is similar to aerosol cans that dispense foods such as whipped cream and soft cheese.

Coca-Cola's can is lined with a laminated plastic bag filled with cola that overlays a second plastic bag containing carbon dioxide under 50 pounds of pressure. The carbon dioxide forces the cola out of the can.

One drawback to both colas is that they will have to be drunk unchilled by the astronaut crew.

The crew is made up of C. Gordon Fullerton; Roy D. Bridges Jr.; Dr. F. Story Musgrave; scientist-astronauts Anthony W. England and Karl G. Henize, and payload specialists Loren W. Acton and John-David Bartoe.

The soft-drink cans will be chilled and insulated when they are put on board, but because there is no refrigerator on the shuttle the drinks will be warm by the time the crew gets around to drinking them.

"We don't mind," Williams said. "Pepsi tastes great at any temperature."