Federal investigators are exploring whether Lockheed Aircraft Corp. has been illegally providing technical data about solid rocket propellants to South Korea, according to court documents made public in Washington yesterday.

In connection with the investigation, Customs Service agents searched Lockheed corporate offices here and in Ontario, Calif., this week and said they recovered numerous documents that may be relevant to the possible violation of criminal statutes concerning the export of such way materials.

Affidavits in support of the search warrants said the possible "crime being committed" related to whether the company was providing data to Korea about "arms, ammunitions, and implements of war."

The affidavits claimed that Lock heed applied to the Munitions Control Office of the state Department in late 1974 for permission to provide data on propellants to Korea, but asked a few months later that the application be withdrawn. The government claims that the technical data has been provided anyway by the company despite the lack of a permit.

Lockheed officials issued a statement after the searches saying the firm had the express approval of "the appropriate U.S. government agencies" to sell manufacturing equipment to an American-based firm for resale to the south Koreans and merely assisted in the installation of the equipment, also with the approval of U.S. government agencies.

The statement also said the company "has consistently cooperated" with government agencies in other investigations and "feels that the search and seizure of the documents in this instance was completely unnecessary and unjustified."

The searches were carried out around 5 p.m. Tuesday at the Lockheed Aircraft Service Co. offices in Ontario, Calif., and at the Washington office of Lockheed at 900 17th St. NW at the start of business on Wednesday. The warrants and supporting materials were filed secretly in court and unsealed yesterday morning when agents reported back with a list of seized documents.

The Washington search was based on statements to Customs Service agents by Lockheed international relations manager G.F. Carey Jr. that he had in his office documents and diaries concerning the Korean - Lockheed relationship, according to court records.

The affidavit in support of the California search warrant, signed by Customs Service agent Thomas C. Neill, recounts numerous conversations with Lockheed officials about activities in connection with Korea.

A Lockheed vice president was quoted as telling Neill that about 12 persons had been sent by the firm to Korea "to reinstall propellant equipment" in connection with a contract there. No further description of the propellant or the rocket could be obtained yesterday.

Another Lockheed employe said he made three visits to Korea between November 1975, and April 1976, to observe and comment on the construction of a propellant manufacturing facility, Neill said in the affidavit.

Yet another Lockheed official was quoted as saying he had traveled to Korea in 1976-77 to help establish a quality control system for the manufacture of the solid rocket fuel.

A State Department license is required for any export of guided missiles, ballistic missiles, rockets and technical data relating to such articles, according to the court files. Each violation of this section of the Arms [WORD ILLEGIBLE] Control Act carries a maximum penalty of $100,000 and two years in prison.