MOSCOW -- For decades the world's largest space port, a remote launch complex in Kazakhstan on the steppes of central Asia, has been omitted from Soviet maps and generally barred to western visitors.

But the Baikonur Space Centre is where the Proton rocket is launched, and because the Soviet government would like to market its services, some things at Baikonur have changed.

In late November, when the temperature on the steppes was already 20 below zero centigrade, Art Dula, an ebullient American lawyer from Houston, along with his insurance agent and a technical adviser, sat down to tea with the Baikonur chief of launch operations on the floor of the Proton assembly building. The visitors were given a tour of the Proton launch complex and related facilities, including a modern hotel a 45-minute drive away in a town constructed especially for the Baikonur work force.

Not only were they the first Americans to visit the site since 1975, but they were there for one very capitalistic reason -- so they could go back to the United States and find customers for the Proton at $25 million or so per launch.

On the high frontier now, according to a new breed of Soviet space merchants, the top priority is the bottom line.

In the wake of the Challenger space shuttle disaster and other western failures, these venture communists have moved aggressively into the sudden vacuum in western markets confident that they have a product, as an American television ad might put it, not sold in any store -- the ability to put satellites into space.

In addition to launches, the Soviet space bazaar also offers satellite photos more detailed than those sold to the public in the West; lease or purchase of Gorizont communications satellites; lease of microgravity equipment, and room on the space station MIR for scientific payloads, with prices starting at $15,000 per kilogram.

The opening up of Soviet space services has potentially significant implications both inside and outside the Soviet Union. It has fueled the move toward a new openness about long-secret facilities and operations, a change considered essential if the Soviets are to gain credibility with potential customers. It also has moved into influential position a putatively civilian agency that some experts say has been given an unprecedented degree of power over the entrenched military space bureaucracy.

In the 1990s, a National Aeronautics and Space Administration task force recently speculated, "commercial rivalries may play a role analogous to that played by political and prestige rivalries" during the age of Sputnik and the moon race in mobilizing the American space program once again.

But so far, the main impact of the Soviet selling job in the United States has been to embarrass the government. In what critics describe as a response motivated mainly by nationalistic pride, U.S. officials have blocked most would-be customers in the West with official restrictions on deals with the Soviets.

At a time when the launch-poor West has a backlog of satellites and other payloads in need of a boost into space, the Soviets are selling cargo space on six classes of launch vehicles at prices half or less what anyone else is offering, and are preparing to sell space on the world's largest booster, their new Energia, which can carry up to 100 tons into low Earth orbit.

Administration officials, led by Defense Department aides, state firmly that they will not approve export of U.S. satellite technology for launch on Soviet rockets, primarily on grounds that it could give the Soviets access to American hardware vital to national security. In response, the Soviets have agreed to allow security teams to guard the equipment while it is in Soviet territory.

The restrictions so far have discouraged other western nations as well from buying Soviet services, because most of their satellites incorporate U.S. technology.

Patronizing Soviet products also risks making the United States dependent on them, defense officials warn, and fattens the coffers of the hostile Soviet military, which controls space operations.

U.S. officials also argue that doing business with the Soviets would kill the fledgling U.S. commercial launch industry, and some say this is the real reason for the restrictions.

So far the Soviet launch salesmen have only one known customer outside the East Bloc, an Indian remote sensing satellite to be launched soon on a Vostok rocket. Asked if there are any others, Stepan Bogadyesh, chief of international relations for Glavkosmos, the powerful agency set up in late 1985 to "coordinate the Soviet space program for the good of the economy," said, "That's a commercial secret."American Companies at Odds

General Motors and General Electric, which have subsidiaries that market communications satellites, are among companies that have pressed the U.S. government to drop its restrictions and let them "buy Soviet." Pitted against them are companies trying to develop a profitable commercial launch industry in the United States under a new Reagan administration policy.

Dula and the Soviets say they are pushing for sales of only two or three Proton launches per year. "That's very significant," said space analyst John Pike of the Federation of American Scientists. "That means they're not trying to corner the market, or wreak havoc. They want to pick up a little money and relax tensions."

"Today, a large queue has been formed in the world for the launching of satellites," said Alexander Dunayev, the assertive, sometimes gruff man who heads Glavkosmos.

"I think the queue will do its job, and the West will arrive at an understanding that it is not worth putting up fences of far-fetched embargoes in commercial space," he said.

Glavkosmos (Chief Administration for the Development and Use of Space Engineering for the Economy and Research) is headquartered in a long, yellow brick building that resembles a garden apartment complex. Original oil paintings of space by Soviet artists decorate the office walls.

Some observers speculate that Dunayev has simply taken off his general's uniform and changed the name of an existing agency in order to "civilianize" the rocket marketing effort. "Nobody knows" Dunayev's background, said Dula.

According to Nicholas Johnson, a Soviet space expert at Teledyne-Brown in Colorado, Glavkosmos was the apparent winner in "a power struggle to control the Soviet civilian space program" and several older agencies are now subordinate to it.

Some Defense Department officials question whether Glavkosmos can give orders to the military bureaucracy that controls space flight operations. But Johnson said it must have some voice in scheduling and operations if it is to deliver on its promises to customers.

The Houston attorney said his visit to Baikonur was tightly controlled, he was not allowed to take pictures and he felt some "stiffness" in some of the Soviets he met there, as if his visit under the auspices of Glavkosmos might have been forced on them.

"Glavkosmos deals in iron, in technologies," said Bogadyesh. "We are designers and constructors. We provide different works, satellites, for different branches {of the bureaucracy}, and also coordinate, schedule the program of launches. Besides, we determine the flight program of specialists."

The U.S. position on the marketing of Soviet satellite photos is less clear than that on the launch vehicles. The dying U.S. Landsat program has all but surrendered to the French Spot operation -- in part, experts said, because that market has been unexpectedly slow to develop.

Now the Soviets are offering satellite images that are by all accounts two to six times more detailed than either western nation is offering, but with other technical limitations. For instance, they can't be computer-manipulated the way the western images can.

U.S. military satellites are capable of photographing objects much smaller than the Soviet offerings, down to a few inches, specialists said. But these photos are classified.

"For 30 years, we had to go through the ministry of foreign trade to make deals with foreign countries," said Vyacheslav A. Piskulin, the pin stripe-suited director of Soyuzkarta, the organization that sells the photos for the Main Administration for Geodesy and Cartography of the Soviet Council of Ministers. "Now we have the right to promote every kind of foreign activity and conclude contracts on our own."

The Soviets offer photos of just about anything -- except Soviet territory, Piskulin said.

Ironically, the U.S. Geological Survey has asked for administration approval to buy Soviet photos of American locations, including Washington, for a test project it is working on, according to Frederick Doyle, an official in the mapping division and former president of the International Society for Photogrammetry and Remote Sensing.

"There is no clear decision" yet about U.S. government policy regarding the sale and purchase of Soviet satellite photos, said Michael Michaud, acting deputy assistant secretary of state for science and technology affairs. "It is a much newer area" than the launch vehicle market.

The factors being weighed include "the extent to which the Soviets play by the international rules of the game, and make their data available on an open and nondiscriminatory basis, as Landsat does," he said. Piskulin said repeatedly that the Soviets are "following U.N. rules." National Security Considerations

In this country, regulations issued recently by the Commerce Department give the State and Defense departments a veto power over public acquisition of satellite photos on the open market in case they pose a national security threat.

"It's ironic that an open society like ours is protesting the release of pictures by a closed society," said James Harford, director of the American Institute of Aeronautics and Astronautics, who paid Soyuzkarta $1,147 for film and prints of the Columbia River delta in Oregon for publication in the organization's magazine.

Piskulin said Harford was Soyuzkarta's first paying American customer.

While their global door-to-door sales pitch is new, the Soviets have long attached great importance to the economic benefits of space technology within their country. Several officials referred in interviews to the great value they place on being able to reach 90 percent of their vast territory, with its 11 time zones, by state-run television.

Dunayev said the use of satellites rather than cables saves more than 100 million rubles a year, and the use of satellite photos can cut geological survey costs of prospecting for minerals by 15 to 20 percent. In general, the use of space technologies would amount to savings of "one billion rubles to five different categories of users over the next five years."

Although the Soviets' progress from secrecy to openness in pursuit of profits has been halting and selective, they have gradually revealed previously guarded details of vehicles, facilities and plans. Their offer to allow western security agents to protect western technology inside Soviet facilities was regarded by many as a particularly significant gesture.

"My impression is that these folks are really serious about being real players in the world, in a way they weren't before," said space policy analyst John Logsdon of George Washington University.

"The security of the technology and the company's 'secrets' of the test hardware and information during the transportation across the U.S.S.R. and the prelaunch checkouts are guaranteed by granting the right to the technical personal team accompanying the spacecraft to be present at all stages of the spacecraft preparation for the launch," says a Soviet pamphlet published in English.

Another brochure outlines for customers technical details on subjects such as the vibrations and potential stresses of transporting a satellite to Baikonur on an Aeroflot plane (no other transport is allowed) and provides diagrams and descriptions of ground facilities at Baikonur and safety rules.

Though it was first launched in 1965, the Proton rocket for two decades had remained a mystery except for glimpses of it in a few photos or film clips. With the launch of two scientific planetary probes in 1984 by Space Research Institute here, the Soviets released film of the Proton at liftoff. In 1986, a flood of technical information and photos almost totally demystified it. The Soviets even identified seven failures in 97 launch attempts for one variant of the rocket, although U.S. space experts say some failure statistics were omitted.

Now potential customers can pick up slick color brochures with pictures of Proton and specifications on the rocket's performance, power and other aspects.

Still, much of the Soviet space bureaucracy remains hidden. "They are trying hard not to let us understand how it works," said Jacques Blamont, chief scientist for the French space agency, which has cooperated with the Soviets in space for two decades. "But if Glavkosmos wants to sell Soviet products, they must become civilized."

Some U.S. government officials argue that the Soviets' wares are unfair competition because they are heavily subsidized by the government. Dula and others say the Soviets' low prices for launches are primarily the result of their efficiencies of scale gained by mass production and launching their rockets often, an average of two a week. "They are just trying to be good capitalists," Dula said.

Some potential customers in the satellite industry express reservations about the Soviet launch services in any case. The Proton is said to have vibrations that might affect delicate U.S. satellite technology, and questions have been raised as to whether "clean rooms" (satellite processing rooms) are really clean by western standards or might allow moisture or dust to foul sensitive satellite innards. Soviet satellites are of simpler designs that do not require such hothouse treatment.

But the Soviets may soon be able to offer a unique service that will be hard to resist -- the ability to lift up to 100 tons to orbit, or more than three times the U.S. shuttle capacity, on their new superbooster, Energia.

No one else in the world will have anything to match the 200-foot-tall Energia, which made its first test flight in May, until at least the early 1990s, U.S. experts say. Energia is a versatile system with at least four planned configurations, which the Soviets say will be used to carry their version of the shuttle into space, launch large manned modules for assembly in orbit, launch space science missions into deep space, and place experimental solar power plants in orbit.

In one possible configuration, using a new third stage with strap-on boosters, Dula said, Energia could carry 200 tons to low orbit. This means it could carry the proposed U.S. space station in a couple of trips, instead of the two dozen and more anticipated using the U.S. shuttle, he said.

Before Energia can become operational, the Soviets must continue testing and eliminate a few "bugs," according to Bogadyesh, who said he previously worked at Baikonur in space research and flight control operations. "Then we will sell."

The next launch will probably be this year, he said.

The Soviet version of the shuttle, which Defense Department officials say is based heavily on U.S. technology, will also become operational "in the near years," according to Bogadyesh. Referred to here as the "multipurpose rocket," he said, it is having problems with flight control systems and boosters.

A jet-powered version of it is being tested at Baikonur by Igor Volk, a muscular cosmonaut with thinning red hair who socialized with American astronauts and scientists attending a recent space forum here. During a general exchange of good-will tokens over hors d'oeuvres one evening, astronaut Kathryn Sullivan handed him a lapel pin commemorating the first flight of the U.S. shuttle.

For its initial orbital test flight only, the "shuttleski," as some Americans refer to it, will be flown unmanned and commanded from the ground if possible, Bogadyesh said. This idea is opposed by some members of the cosmonaut corps, according to Aviation Week and Space Technology magazine.

While they acknowledge with increasing candor the problems in their space program, the Soviets are also arguing with mounting forcefulness that the world needs what they are selling -- and that they are not in a position to be effective techno-thieves although they try. Insufficient Infrastructure

Yevgeni Velikhov, vice president of the Soviet Academy of Sciences, echoed several Soviet and American officials when he said, during an interview in his office, that the Soviets have trouble using certain advanced technology, such as main-frame computer technology, even when they can get it.

"Our problem is not technology; it is infrastructure . . . . We have not spent enough money on factories, clean rooms and machines -- what it takes to make a big industry."

Pike, of the Federation of American Scientists, agreed, saying, "The real problem is not their getting hold of a chip. It's process . . . . They have no infrastructure."

Velikhov, who has on his office wall an American bumper sticker that says "Computers for Everybody," argued that it hurts the United States not to let "the flow of cooperation go both ways . . . . We have the potential to benefit every nation who works with us. The potential in space is quite big."

He cited recent examples of cooperation between the Soviets and the United States, such as one under which the Soviets are sharing their advanced technology in nuclear fusion reactors.

"We are getting criticized by our own people for giving this so freely. But for a long time we keep {the technology} secret, the result was bad for us. Now we have talented and creative people from the U.S. working on {the project}. There is much benefit from cooperation."

After all, he said, smiling, "Does not the U.S. Congress sit under the dome of the Capitol? This is a transfer of technology from St. Petersburg, which made the first big metal dome."