Orbital Sciences Corp. has been issued its first license for commercial space launches, giving the Fairfax County company a foothold in a slow-developing market that finally may be taking off.

The Department of Transportation issued the license for three launches, all of which will be used to conduct experiments on the impact of weightlessness on payloads for the Center for the Commercial Development of Space at the University of Alabama in Huntsville. The Huntsville facility is one of 16 such centers around the country.

All told, DOT has 19 launches slated for this year, more than double the eight commercial launches that took place in 1990. Some 33 are on the books for the next four years.

For most of last decade, the commercialization of space has been anticipated more than it has been realized. Despite efforts that began in the early 1980s, the first commercial space launch in the United States didn't take place until 1989. "It's taken awhile to get off the ground, but we feel this is a significant and growing industry," said Chuck Kline, associate director for program affairs in the DOT's Office of Commercial Space Transportation.

The goal is to develop a commercial space industry that can serve both commercial and government customers. Until recently, the government has been the sole customer of major rocket companies such as McDonnell Douglas Corp., Martin Marietta Corp. and General Dynamics Corp. As commercial uses develop, the economics of such launches should improve so the costs to the government and other customers go down.

"When the government wants to move something from Washington to Los Angeles, the government doesn't go out and buy a truck and hire a driver," said Kline. "The idea is to move space transportation in the same direction."

Orbital launched an experimental winged Pegasus rocket from a National Aeronautics and Space Administration B-52 bomber last year, demonstrating a new, low-cost method of putting satellites into orbit for the Defense Department and others. The Defense Advanced Research Projects Agency has subsequently exercised options on Pegasus vehicles worth approximately $35 million.

Orbital will use a different technology for the DOT-licensed flights, launching Prospector rockets developed by the company from a Cape Canaveral launch pad refurbished by Orbital. The first launch will be in March, with additional ones in December and in December 1992, the latter being one of 15 the company has scheduled for next year.

Currently, the government dominates the market for launches, with approximately 90 percent of contracts coming from the government and 10 percent from private commercial customers, said Barbara Zadina, manager of government and external relations for Orbital. She said the company hopes that growth in the commercial market for space launches will change that mix to closer to 50-50. The Pegasus launch and other milestones last year marked "the dawn of a new era in commercial space," said Zadina.

Orbital offered its stock to the public for the first time last April, after delaying it several weeks when an article in the Wall Street Journal raised doubts about the Pegasus project. After the successful launch of Pegasus, the company found buyers for all 2.4 million of the newly issued shares.

Since then, the Orbital reported a third-quarter profit and narrowed its losses in the first nine months as a result of revenue increases from the sale of Pegasus.