Thomas Gilmore Pownall, the savvy and hard-nosed executive who repelled a hostile takeover of Martin Marietta in the 1980s and guided the company's transformation into one of the country's leading defense electronics firms, died June 24 of pneumonia at Manor Care Potomac. He was 83 and a resident of Potomac.

Mr. Pownall, former chairman and chief executive of Martin Marietta, achieved corporate celebrity status in 1982 when he led the company's defense during a 33-day test of financial wills against the larger Bendix Corp. His strategy to gobble up the competition before it could consume Martin Marietta was christened the Pac-Man defense by Wall Street analysts.

On Aug. 26, 1982, the day after the $1.5 billion unsolicited bid for his company was announced, a Martin Marietta board member took off his necktie decorated with naval pennants declaring "Don't Give Up the Ship" and handed it to Mr. Pownall. He donned the tie and with the backing of his board launched a counterattack on Bendix. He later said he wore the tie every day during the takeover battle.

The Bethesda-based aerospace company retaliated by making a $1.6 billion offer to buy Bendix, a major supplier of auto parts, electronic equipment and machine tools. Martin's initial counterattack was aided by United Technologies Corp. In the end, Allied Corp. bought out Bendix and exchanged stock with Martin Marietta. The company retained its independence but was strapped with $900 million in debt.

Mr. Pownall, known as a dominant and decisive manager, was credited with quickly eliminating the debt and reshaping the corporation into the defense and aerospace firm that later became the merged Lockheed Martin Corp.

"I understand the aerospace business as well as most of my peers in the business do -- as well as any," Mr. Pownall told a New York Times interviewer in 1983. "I'm talking about the entirety of it -- military establishment, generation of requirements, long lead times -- for example, the Viking program. We began looking at ways to get to Mars in 1964. We got a contract in 1969. We launched a vehicle in 1975. It landed in 1976. We got our award fee in 1977."

A farmer at heart, Mr. Pownall was born in Cumberland, Md., where his mother was visiting. He grew up on a large farm in Moorefield, W.Va. He graduated from Mercersburg Academy in Pennsylvania, where he was captain of the football team. At the University of West Virginia, he took mostly physical education courses until his father found out and kicked him out of the house.

He worked in construction for a spell and eventually, through family connections, he received an appointment to the U.S. Naval Academy. He played football as a guard and earned a commission as ensign with a degree in electrical engineering in 1946.

He served two years aboard a destroyer in the Pacific during the Korean War and often told colleagues his decision to leave the Navy was the biggest mistake of his life.

His career covered several industries -- in the paper box business, as a salesman for a steel fabricator and for General Motors' Chevrolet division in Ohio before joining the Convair division of General Dynamics Corp. in San Diego in 1955. He transferred with General Dynamics from California to Ohio and then to Washington. A couple of years later, he joined Fairbanks Morse, which made engines.

Politics beckoned briefly in 1952 when he worked as an advance man in the presidential campaign of Dwight D. Eisenhower and again in 1960 for Richard M. Nixon.

He joined Martin Marietta in 1963 as vice president for advanced planning for its aerospace company. He quickly rose to president of the company and a vice president of the parent corporation in 1969. He was elected to the board of directors in 1971, president and chief operating officer in 1977, chief executive in 1982 and chairman in 1983, a position he held until his retirement in 1987. He continued on Martin Marietta's board of directors until 1991.

"He was a straight shooter, tough guy and a loving guy, a great combination of all those things," said his daughter Fuzzy Billings.

Mr. Pownall rode horses all his life, and in photos bore a striking resemblance to the iconic Marlboro Man. He started skydiving at age 60 but gave it up when he found it wasn't as exciting as he thought. After retiring, he learned everything he could about farming and bought a farm in Gordonsville, Va., to raise cattle.

He served on the boards of several corporations and was a trustee at several universities. He also was a trustee of the U.S. Naval Academy Foundation and finally trustee emeritus after 27 years.

He also was a longtime member of Burning Tree Club and Congressional Country Club.

Billings said her father put on his coat and tie and went to his K Street office until the day before he was hospitalized.

In 1976, the Air Force Association honored him with its Theodore von Karman Award for outstanding achievement in science and engineering for Martin Marietta's design, development and manufacture of the two Viking spacecraft that NASA landed on Mars in mankind's first exploration of the Red Planet.

In addition to his daughter, of Potomac, survivors include his wife of 60 years, Marilyn Cunnick Pownall of Potomac; a daughter, Suzi Locke of Chevy Chase; a sister; and six grandchildren.

Thomas Pownall