Former astronaut James B. Irwin, who walked on the moon in 1971 and later became a minister who searched for traces of Noah's Ark, has died, a hospital spokeswoman said. He was 61.

Alice Sundeen, spokeswoman for Valley View Hospital, said Irwin died Thursday night, apparently of a heart attack.Irwin, who had had a history of heart trouble, was on a speaking tour of central Colorado Christian organizations at the time of his death. He was the first to die of the 12 men who walked on the moon.

He lived in Salt Lake City from 1943 to 1947 and graduated from East High School.

Irwin viewed his Apollo 15 moon journey in July-August 1971 as a religious experience and said it led him to found the High Flight Foundation, an interdenominational evangelistic organization based in Colorado Springs.

Former astronaut Alan Bean rembered Irwin Friday as "a wonderful human being. He was a wonderful astronaut because he was such a good team player. He could decrease his own ego to work with people in Apollo to make a better mission."

In a telephone interview from his home in Houston, Bean said he had run into Irwin just a week ago, and "I know he had so many plans for the future."

The High Flight Foundation's most publicized efforts involved six expeditions led by Irwin to Mount Ararat in Turkey in an unsuccessful searchfor remnants of Noah's Ark.

"Some people make light of it and ask how can a technical person, an astronaut, believe in the Bible," Irwin once told an interviewer. "I guess I was also a skeptic in my early days, but I've come to believe what the Bible says as being true."

Irwin said in September 1986 that he was giving up the search for the ark. "I think it is time for others to take up the search," he said.

Irwin retired from the astronaut corps and founded his non-profit foundation, whose main purpose was "to share the love of Jesus Christ," a year after his walk on the moon.

On July 26, 1971, Irwin, David R. Scott and Alfred M. Worden blasted off on their 295-hour flight to the moon and back. Irwin and Scott were the first to use the Lunar Rover vehicle. Among the samples they collected was a rock estimated to be 4.15 billion years old, nicknamed the Genesis Rock.

Irwin said that it was because of that discovery that "I thought the Lord wanted me involved in finding artifacts from the Genesis time that would be more important than the Genesis Rock we found on the moon."

The Apollo 15 crew also was involved in charges of personal misconduct.

Several months after they returned to Earth, it was revealed that Irwin and Scott, while on the moon, had hand-canceled stamped envelopes. Later, these envelopes, made more valuable by the lunar cancellation, were sold to a European stamp dealer.

The three crew members, who resigned within a few months, had received thousands of dollars for their efforts. The National Aeronautics and Space Administration issued a reprimand and changed its policy about what astronauts may carry into space.

"Americans should know that Jim was a true American hero," Worden said Friday. "Full of love, he was certainly very religious. He was certainly a very dedicated guy to doing what had to be done."

Born in Pittsburgh on March 17, 1930, Irwin was a 1951 graduate of the U.S. Naval Academy. Irwin transferred to the Air Force to become a test pilot. He accumulated more than 7,000 hours of flying time and rose to the rank of colonel.

In 1966, he was selected for the Apollo program. He was the author of the book "To Rule the Night."

Irwin is survived by his wife, Mary Ellen, and five children.