Erik Hauri, scientist who found water on the moon, dies at 52

When early astronomers gazed up at the moon, they mistook its dark patches for seas. By the time astronaut Neil Armstrong stepped onto the Sea of Tranquility in 1969, scientists knew it was nothing but terra firma.

Most researchers concluded that the moon was “bone dry,” a celestial desert devoid of water or ice. But in a set of papers published beginning in 2008, geochemist Erik Hauri helped demonstrate that water existed on the moon after all — and that the moon’s interior might contain as much water as the Mediterranean Sea.

Hauri, who was 52 when he died Sept. 5 at his home in North Potomac, Md., helped usher in a new era in our understanding of the moon, an astronomical object now known to have ice on its poles and water deep inside its mantle. He had cancer, said his wife, Tracy Hauri.

A longtime researcher at Washington’s Carnegie Institution for Science, Hauri was first recognized for his work with highly sensitive instruments called ion microprobes, which he pushed “to their absolute technical limits,” said Larry Nittler, a cosmochemist and Carnegie colleague.

Using techniques he developed in the 1990s, Hauri used the instruments to examine slivers of shards, portions of rock the width of a human hair or smaller. He detected trace amounts of elements such as hydrogen and carbon, down to a few parts per million — work that enabled him to obtain key insights on the Earth and moon.

A onetime marine biology student, Hauri began studying rocks after deciding marine animals were fickle and uncooperative. But he spent much of his career outside the lab, collecting volcanic samples from Hawaii, Iceland, Alaska and Polynesia that shed light on the movement of elements and minerals deep inside the Earth.

He was focusing on water, which has a broad impact on volcanic eruptions and the movement of tectonic plates, when his friend Alberto Saal suggested they conduct measurements for hydrogen, water and other volatile substances using the lunar samples of the Apollo program.

“When people measured these moon rocks they never found anything,” said Saal, a Brown University geochemist who attended graduate school with Hauri at MIT and the Woods Hole Oceanographic Institution. “We had a good technique. Nothing had been done on hydrogen for a long time. We said, ‘Why not try?’”

It took three years for the researchers to obtain their samples from NASA, which twice rejected their research proposal, Saal said. But when he and Hauri reviewed their findings, “It was like a bomb had exploded in our hands.”

Erik Harold Hauri was born in Waukegan, Ill., 40 miles north of Chicago, on April 25, 1966. He grew up in Richmond, Va., a small town near the Wisconsin border, where his mother was a homemaker and his father was an auto mechanic and avid fisherman, taking Erik on trips that spawned a lifelong interest in the outdoors.

In addition to his wife of 31 years, the former Tracy Spears of North Potomac, survivors include three children, Kevin Hauri of College Park, Md., Matthew Hauri of Silver Spring, Md., and Michaela Hauri of Pittsburgh.