RICHMOND, OCT. 8 -- Former Navy intelligence analyst Samuel Loring Morison, backed by a number of major news organizations, asked a federal appeals court today to overturn his 1985 espionage conviction for leaking classified spy satellite photographs to the press.

Morison's lawyer, Mark H. Lynch, maintained at an hour-long hearing that Congress never intended the espionage laws to be applied to leaks to the press and that Morison's conviction, if sustained, would set a dangerous and chilling precedent.

But U.S. Attorney Breckinridge Willcox of Baltimore -- where Morison was convicted -- portrayed him as a "venal" man who "stole photographs belonging to the government" to curry favor with a British magazine from which he wanted a job and then, when he was caught, tried to wrap himself in the First Amendment.

In a 49-page brief, the news organizations said that no one had ever before been convicted of a crime for disclosing information to the press or the public. And since Morison was convicted of theft as well as espionage, they argued, "the simple receipt of 'nonpublic' documents may expose the press to prosecution . . . whether those documents relate to the national security or to the national parks."

"Congress never intended these results, and those who adopted the First Amendment never would have tolerated them," the news groups said.

The friend-of-the-court brief was signed by The Washington Post, The Wall Street Journal, The New York Times, eight other major newspapers, the three major television networks, Time, Newsweek, U.S. News & World Report and 14 other organizations including the Associated Press, the American Society of Newspaper Editors and the American Newspaper Publishers Association.

Free on $100,000 appeal bond, Morison, the 42-year-old grandson of the late naval historian Samuel Eliot Morison, listened attentively from a spectator's seat in the green-carpeted courtroom.

He was sentenced to two years in prison for sending Jane's Defence Weekly three secret U.S. spy satellite photos of the Soviet Navy's first nuclear-powered aircraft carrier under construction at a Black Sea shipyard.

The Weekly, an offshoot of Jane's Publishing Co. for which Morison worked part time as an American editor, published the pictures in an August 1984 edition with a story concluding that work had been speeded on the 75,000-ton flattop.

Two of the three members of the appeals court panel, J. Dickson Phillips Jr. and Harvie Wilkinson III, asked pointed questions of both sides.

Wilkinson said he agreed with Lynch that the wording of the espionage law in question is "extraordinarily broad language," but he also said the trial judge in the case, Joseph H. Young, seemed to have made a real effort to limit its scope in his instructions to the jury.

Lynch contended that Young's instructions were still inadequate, such as the judge's holding that the classification system was a definitive guide under criminal law for judging who was "not entitled to receive" defense information. Lynch also faulted Young for failing to tell the jurors more clearly what kind of damage Morison's disclosures needed to have produced.

Willcox assured the court that "the government would be very, very loath" to apply the espionage and theft laws to the press. He also attacked Morison's motives.

"He did it for his own personal venal purposes," Willcox said. "He wasn't trying to educate the world."

Judge Phillips suggested that the government was trying to have it both ways. He pointed out that the prosecutors at Morison's trial fought hard, and successfully, to block any evidence about Morison's patriotism.