A Federal prosecutor assailed former Navy intelligence analyst Samuel Loring Morison today as a "petty, vain, arrogant person" who put himself above the law in leaking classified photos taken by the secret KH-11 spy satellite.

Assistant U.S. Attorney Michael Schatzow made the charges in a stinging summation here this afternoon as Morison's espionage trial drew near a close. The jury began its deliberations just before 5 p.m., then adjourned for the night about 75 minutes later.

Defense attorney Robert Muse protested in his closing arguments that Morison "may have been wrong" in sending to a British magazine last year three KH-11 photos, showing the Soviet Union's first nuclear aircraft carrier under construction at a Black Sea shipyard. But Muse insisted that his client's conduct was far short of criminal.

He said the leaking of classified information was a common occurrence in Washington and suggested there was a strong whiff of "hypocrisy" in the government's singling out a low-level bureaucrat such as Morison for prosecution.

"If you stopped leaking in government, you wouldn't know anything," Muse told the jurors at one point. "In our government, daily, regularly, people are sending it out."

Schatzow denounced such talk as "an invitation to lawlessness."

"Mr. Muse says it's not a crime," the prosecutor said in scornful tones. "If Mr. Muse doesn't like the laws in this country, he can get on his soapbox and go down to Washington and change the law. What Mr. Muse is asking you to do," Schatzow said, pointing at Morison with a scowl, "is to do the same thing that that man did . . . ignore your oath."

Morison, a civilian analyst at the Naval Intelligence Support Center, is charged with of espionage and theft for sending the photos to Jane's Defence Weekly and for taking home portions of two other classified documents.

Muse depicted Morison as a loyal American and Vietnam veteran whose overriding interest was in a strong Navy and whose primary motive was in alerting the American public to a growing Soviet threat on the high seas. He emphasized Morison's longstanding status as American editor of Jane's Fighting Ships, a companion publication to Jane's Defence Weekly, and maintained that the information about the KH-11 that could be gleaned from the photos was already well-known to the Soviets.

The defense attorney also derided the idea that the documents found in Morison's apartment, dealing with a series of 1984 explosions at a Soviet naval ammuniton dump, were "potentially damaging" to the United States.

Muse acknowledged that Morison had sent a summary of the explosions incident to Jane's, but said there was "nothing in Jane's" that had not been mentioned in other publications.

Schatzow and fellow prosecutor John Douglass, however, argued that Morison must have known he was breaking the law because he "lied" repeatedly when first questioned in the summer of 1984.

Although U.S. District Court Judge Joseph H. Young has already ruled that Morison's motives were irrelevant, Schatzow voiced skepticism about the defense claims that Morison wanted to alert the American public through the medium of a British magazine where he was seeking a full-time job. "He didn't send it to CBS," Schatzow declared. "He didn't send it to The Washington Post. He sent it to Jane's."

The prosecutor maintained that a full reading of all the correspondence between Jane's executives and Morison over the years, as Muse urged the jury to undertake, would show the defendant as "a petty, vain, arrogant person. And that arrogance," Schatzow asserted, "is the key to this case in terms of what motivated him."

Both sides rested after the government called two final rebuttal witnesses this morning in an effort to counter the testimony of a retired CIA career officer, Roland S. Inlow, who turned out to be the strongest witness for the defense.

Inlow, who helped develop the KH-11 and for a decade headed the interagency committee in charge of U.S. spy satellites, said he saw "zero" damage from publication of the photos in Jane's -- in light of what the Soviets already knew.

In rebuttal, retired Army Brig. Gen. Rutledge P. (Hap) Hazard, who also served as head of the National Photographic Interpretation Center, said he felt the disclosures gave the Soviets a fresh opportunity to review and modify any programs they might have had to frustrate KH-11 reconnaissance.