Rep.-elect John L. (Jack) Swigert (R-Colo.), whose methodical drive and intellect brought a crippled spacecraft back from the moon 12 years ago, died Monday night of bone cancer at Georgetown University's Lombardi Cancer Institute.

The 51-year-old former astronaut learned only in September he had the disease, and had vowed to conquer it with the same tools he had used in space.

"I believe that with technology and commitment we can overcome any challenge," he told voters in suburban Denver as he campaigned this fall.

He campaigned for eight or nine hours a day despite exhausting chemotherapy treatments, won election to Colorado's new 6th District seat with 63 percent of the vote and two weeks ago was lobbying by phone for House committee assignments.

By Dec. 19, however, when he was airlifted to Washington for treatment from his home in Littleton, Colo., cancer had spread to his lungs and his decline was rapid, according to his press secretary, June Weiss.

"But Jack was not one to believe there weren't alternatives," Weiss said yesterday. "I expect he believed that up through last night."

Colorado Gov. Richard Lamm is expected next week to call a special election to fill the vacancy created by Swigert's death, an aide to the governor said.

A Colorado native, Swigert was pilot of the Apollo 13 moon mission that was launched April 11, 1970. Two days later, as the spaceship orbited the moon preparatory to a landing, an oxygen tank exploded. The moon landing was scrubbed after the blast cut off the command capsule's electric power, computer capability, water and oxygen supplies and threatened to maroon Swigert and two other astronauts in space.

"Houston, we've got a problem," Swigert radioed back to earth. Three-and-a-half days later he and the other crew members brought the crippled spacecraft safely home.

The oldest of three children, Swigert was graduated from Denver East High School in 1949 and the University of Colorado in 1953 with a degree in mechanical engineering. He received a master's degree in aerospace science from Rensselaer Polytechnic Institute in 1965 and an MBA from the University of Hartford.

He was an Air Force fighter pilot in Korea from 1953 to 1956 and narrowly escaped injury when his plane crashed and burned after striking radar equipment on a Korean airstrip. He was a test pilot for 10 years before joining the NASA space program in 1966, and served with support crews of the Apollo 7 and ll missions before piloting Apollo 13.

In 1973 he was named executive director of the Committee on Science and Technology of the U.S. House of Representatives, and in recent years had served as vice president for administration and corporate affairs of International Gold and Minerals Ltd., of Denver.

Swigert ran unsuccessfully for the U.S. Senate in 1978 against Sen. William Armstrong (R-Colo.) with whom he subsequently became close friends. Armstrong was with him when he died, according to Weiss.

He was heavily favored from the start of his congressional race last year, and hardly slowed his campaign when doctors early last summer discovered and removed a small malignant tumor in his right nasal passage. He made the diagnosis public and easily incorporated five-minute radio-therapy treatments into his 15-hour workdays.

A detailed NASA yearly physical in August--a routine followup for all astronauts--disclosed no trace of cancer, Weiss said, but left Swigert complaining of lower back pain. The pain grew worse during subsequent weeks and two days after the Sept. 14 primary he entered Denver's Presbyterian Hospital for 11 days of exhaustive tests.

When the tests disclosed no reason for the pain, doctors drilled into his hip for a sample of bone marrow. The results of the analysis left him stunned, Weiss said.

"He walked into his room and stood there a minute," she said. "Then he said, 'Well, I licked the other one, I can lick this one, too.' "

Two days later, at a news conference in suburban Littleton, outside Denver, he announced "I have a new challenge to meet."

Subsequent chemotherapy treatments left Swigert very, very tired, Weiss said, but visibly better. The back pain disappeared.

Dr. Robert Sawyer, Swigert's physician, said he believed doctors found the bone marrow cancer during an early stage. He said at the time Swigert's chances of surviving the cancer were "probably better than those for getting back from the moon in a broken spaceship."

Shortly before Thanksgiving, however, Swigert entered Denver Presbyterian with a low-grade temperature and intermittent nosebleeds. Subsequently he took his medical records to M.D. Anderson Cancer Research Institute in Houston for another day of tests. He was forced to miss an orientation session for new congressmen (Weiss attended in his place) but vowed to attend swearing-in ceremonies Jan. 3.

Weiss said Swigert, who never married, was a practicing Roman Catholic but rarely talked of his faith or of facing death.

"He was one of those people who felt very sincerely that we as a society had some great things still to do," she said. "The only time I remember him making any reference to dying was shortly after the bone-cancer diagnosis. I was driving him to a TV spot and he said: 'When I think of all the people who don't have things they want to accomplish, I have to ask "why me?" ' "

Weiss said funeral arrangements were incomplete, but Swigert probably will be buried in Colorado.

He is survived by his mother, Mrs. John L. Swigert Sr. of Denver, and two sisters.