A citizen of Belgium was indicted by a federal grand jury yesterday for allegedly offering up to a half-million dollars on behalf of a Soviet company to buy a trade secret from a Northern Virginia computer programming company.

Marc Andre DeGeyter, 31, of Schilde, Belgium, was charged with participating in an industrial espionage scheme to buy a secret data management system from Software AG of North America Inc. a Reston-based company, according to the indictment.

DeGeyter allegedly said he was seeking the trade secret for a Soviet company indentified as Techmashimport, a Moscow-based foreign trade company, according to the indictment returned in U.S. District Court in Alexandria.

DeGeyter was arrested May 18 at New York's Kennedy International Airport moments after he allegedly handed a half-million-dollar check to an undercover agent in exchange for two reels of computer tape, according to court records in New York.

The indictment does not say whether the Soviet company, which is licensed to do business in the U.S., was aware that DeGeyter was allegedly attempting to obtain the program for the Reston company's ADABAS data management system.

DeGeyter is charged with eight counts of traveling both inside and outside the US. since May 1979 to commit commercial bribery by allegedly offering from $150,000 to $500,000 for the computer program.He could be sentenced to up to 40 years in prison and an $80,000 fine if convicted.