While much has been said and written about the possibility of a shooting war in space between the United States and Soviet Union, the real war in space is an economic one, between the United States and the European Space Agency (ESA).

The fight is over who gets to carry into Earth orbit the major part of the growing commercial traffic in communications, weather and navigational satellites. So far the United States is way ahead of the Europeans because the seven flights of the manned space shuttles Columbia and Challenger have been huge successes, while two of the six flights of the ESA's unmanned Ariane launch vehicle have ended in failure.

At the start of this month, the ESA had firm bookings for 24 satellites on 16 Ariane flights through November, 1985. The ESA also has reservations for at least 10 and as many as 16 more satellites through 1986, which will be a difficult period because the agency will be testing new engines to allow the Ariane launch vehicle to accommodate larger satellites.

In contrast, at least 72 satellite customers have booked room in the cargo bays of the U.S. space shuttle. Among those customers are ones, such as British Telecom, that might be expected to use the European craft. Australia also booked one of its satellites onto the shuttle, a contract that was understood to be up for grabs. NASA also reserved room for three U.S. satellites (the Fordsat) and three Intelsats that had booked reservations on both the Ariane and the space shuttle before finally selecting the shuttle.

Even more important, NASA was able this month to "steal" one of the ESA's customers. It signed a firm contract with Western Union to carry its Westar 6 communications satellite into orbit in the not-too-distant future. The satellite had already been booked on an Ariane flight.

"This was the first satellite customer anywhere to walk away from either NASA or ESA," Air Force Lt. Gen. James A. Abrahamson, associate administrator of NASA for space flight, said in an interview. "It's not something we want to crow about because we all think competition with ESA is a healthy thing, but Western Union had to pay a penalty to be the first walk-away, and we think that means something."

If NASA isn't crowing about taking Westar from Ariane, it's certainly not upset over drawing first blood in a contest that is bound to get more vigorous in the months and years ahead.

NASA has grown so confident about the shuttle's ability "to deliver," as its astronaut crews have proclaimed each time they've carried satellites into space, that it is now offering customers what amounts to a guarantee that it will reschedule satellites in six to nine months if a shuttle mission has to be scrubbed for weather or mechanical reasons.

The fight for economic footholds in space has just begun. Besides NASA and the ESA, five commercial companies have announced plans to enter the commercial launch vehicle market.

They include Federal Express, which has the marketing rights for Martin Marietta's Titan 34-D launch vehicle; General Dynamics, which seeks to carry satellites into orbit on top of its Atlas-Centaur launch vehicle; Space Services Inc. of Houston, which is developing a low-cost, solid-fueled launch vehicle, and a California company, Starstruck Inc.