Moscow — If all goes well, a Frenchman and two Russians will soon be supping on crab paste, cheese, and lobster aboard the latest Soviet space station. But Moscow clearly hopes the orbiter will score a quite different first before too long - as centerpiece for a large, modular space complex.
For the time being, official Soviet comment is focusing on the planned June 24 launch of a joint Soviet-French crew toward the Salyut-7 station, in orbit since April 19.
But there have been scattered reminders that Salyut-7 is being counted on as the nucleus of a larger space complex the Soviets hope to assemble by adding a series of modules.
The first move toward that goal came almost one year ago, when an experimental module was docked to Salyut-6, a station outwardly almost identical to the new Salyut craft.
Shortly after that linkup, a Soviet cosmonaut explained that the attached module was a ''prototype'' of units that could be used to ''assemble large-scale space operations centers.''
Western experts point out that such a complex would carry clear military potential, as does the American space shuttle. The Soviets, for their part, charge that the shuttle is part of US plans to ''militarize'' outer space. They say the Soviet space program's aims are merely peaceful.
Whatever the aims of either side, there can be little doubt that Salyut-7 figures importantly in stated Soviet plans to assemble a large-scale orbital complex.
Amid Moscow news media celebrations of the new Salyut and of the coming Soviet-French mission, one recent report recalled that the older Salyut-6 remained in orbit with a module ''intended to test the design of future spacecraft.''
The report added that Salyut-7 - recently joined by a Soviet crew to prepare the station for arrival of the Soviet-French mission - was also ''a major step forward in creating a permanently operating orbital station.''
In what Western analysts saw as an indication that Soviets hoped eventually to dock various modules of the sort tested last year, another Moscow report noted: ''The new docking unit of the Salyut-7 station has been improved and is more reliable. . . . It allows larger ships to link up with the station.''
The next visitor to Salyut-7, meanwhile, will be the Soviet capsule ferrying two Russians and one Frenchman late next month - the first time a Westerner will participate in an ''intercosmos'' program. So far the program has been limited to mixed crews involving the Soviets and Soviet-allied states.
The mission will be the first example of a joint Soviet-Western space venture since the linkup of separately launched Russian and US capsules in the Apollo-Soyuz project of 1975.
One key question surrounding the Soviet-French mission is earthbound: Precisely how much propaganda mileage Moscow will seek to make from the cooperative venture at a time of generally strained East-West relations.
The president of the French National Space Studies Center suggested in a recent statement that such publicity would be kept to a minimum. Speaking at a Paris news conference April 21, he said, ''We have made it clear that the operation is not to be carried out for reasons of prestige, but for science. . . . The Soviets have understood our position.''
What publicity the Soviets have mounted so far has been relatively free of explicit political references, and has even included an occasional light touch. An example: the announcement that a ''Moscow institute of the USSR Ministry of Food Industry'' was preparing ''French space dinners'' for the flight. On the menu are ''pate, crab paste, processed cheese, ragout of hare, lobster, and for dessert, orange and strawberry lollies.''