Gerard K. O’Neill; Space Futurist

Gerard K. O’Neill, a Princeton University physicist and advocate of space colonization, died of leukemia Monday at Sequoia Medical Center here. He was 65.

In 1956, O’Neill invented the storage ring principle for colliding particle beams, the basis for most high-energy physics research today.

By the 1960s, however, he was concentrating on the colonization of space, based on the use of solar energy as the power source needed to accomplish what he called the “humanization” of the universe.

In 1977 he wrote in “The High Frontier,” one of his four books, that man’s occupation of space in what he called “Earth-like habitats” would be “the difference between success and failure for intelligent life.”

His envisioned colony, capable of sustaining up to 20 million people, would be contained in giant solar-powered cylinders equipped with almost everything found on Earth, including air, lakes, wildlife, farms and factories.

In 1977, he and his wife, Tasha Steffen, who survives him, founded the Princeton-based Space Studies Institute, which supports research in space development. In 1985, he was appointed by President Ronald Reagan to the National Commission on Space.

At the time of his death he was working on a device called “magnetic flight,” a form of high-speed, ground-based transportation. It is intended to reach speeds that would make it possible to travel from Boston to Los Angeles in an hour.