WASHINGTON — Paul Spudis, a planetary scientist who devoted his career to both the study of the moon and initiatives to return humans there, passed away Aug. 29.

Spudis, 66, was a senior staff scientist at the Lunar and Planetary Institute in Houston, having previously served there as its deputy director. He also worked for several years at the Johns Hopkins University Applied Physics Laboratory in its planetary exploration group.

NASA Administrator Jim Bridenstine broke the news during a meeting of the NASA Advisory Council (NAC) at the Ames Research Center. “He was a guy who lived his entire life really focused on why the moon is important to humanity,” he said, his voice cracking.

“I think each one of us probably has memories of Paul coming to our offices,” said Bill Gerstenmaier, NASA associate administrator for human exploration and operations, at the meeting. “He was a very passionate person about the moon and really wanted the best.”

Spudis’ research career was devoted primarily to the moon. He was the deputy leader of the science team for Clementine, a joint mission of the Ballistic Missile Defense Organization and NASA that orbited the moon in 1994 for technology demonstration and lunar science. That mission included a bistatic radar experiment that detected evidence of water ice at the lunar poles, although some scientists suggested alternative explanations for the observations.

“We were sitting in the control center and watching the big projection screens as the first pictures came in,” Spudis said in an undated interview on the NASA website about his participation on Clementine. “I saw and recognized the crater Nansen, near the north pole of the moon and immediately felt that I’d arrived home. That simple recognition gave me a great thrill — I had always wanted to be part of a lunar mission, and for the first time I had an intimate connection to the little spacecraft orbiting the moon, 400,000 kilometers away.”

Spudis was principal investigator for the Mini-SAR instrument on India’s first lunar orbiter, Chandrayaan-1, launched in 2008, and a team member for a similar instrument, Mini-RF, flown on NASA’s Lunar Reconnaissance Orbiter. The instruments were designed to produce synthetic aperture radar images of the lunar surface and detected potential water ice deposits at the lunar poles.

Spudis was also known as a leading advocate of both robotic and human missions to the moon. He was part of the Synthesis Group, a committee in the early 1990s that developed proposals for human exploration, including a return to the moon. He later served on the Presidential Commission on the Implementation of United States Space Exploration Policy, informally known as the Aldridge Commission, in 2004 to examine President George W. Bush’s Vision for Space Exploration.

He advocated for using the resources of the moon to support human exploration, helping develop mission architectures that showed how water ice extracted from the lunar poles could make missions to the moon more affordable and sustainable. He backed private initiatives to explore the moon as well, serving as chief scientist of Moon Express, a company developing lunar landers initially as part of the Google Lunar X Prize competition.

“Few individuals have been as articulate, passionate, or resolute in their advocacy of lunar exploration and human spaceflight as Paul Spudis,” said Samuel Lawrence, chairman of the Lunar Exploration Advisory Committee, in a statement. “Paul articulated a clear, attainable vision regarding the immense value of going to the moon, establishing a permanent human presence on the surface, and using the resources now known to be abundant on the surface to provide the capabilities required to let us go anywhere, and do anything, we want to do in the solar system.”

Bridenstine made his announcement about the death of Spudis during a discussion of NASA’s exploration plans, including development of a Lunar Orbital Platform-Gateway to support eventual human missions to the lunar surface. “Since we’re talking about the moon, and this is the NAC, I would tell you that he would be thrilled that we’re talking about it,” he said. “We need to move forward for him and all of the other people who have worked so hard to getting us where we are.”