Her sister, Bobbie Cliff, said Dr. Cliff suffered a stroke.
Dr. Cliff’s four decades at NASA—including flights aboard the Space Shuttle Atlantis in 1985 and 1989—covered the program’s early successes and its most crushing tragedies. She was training astronauts in 1981 when Columbia made its first shuttle launch, and was part of mission control in 1983 when Challenger astronaut Sally Ride became the first American woman in space.
Then in January 1986, with one space shuttle mission to go, Dr. Cliff was in a NASA conference room in Houston watching a Challenger broadcast when it exploded 73 seconds into its flight, killing all seven. Crew members including teacher Christa McAuliffe. Dr. Cliff was part of post-disaster teams that evaluated potential design flaws, such as the O-rings that failed in the Challenger’s right solid rocket booster.
“Before my first trip… I said to my family: Hey, I probably won’t come back, because I think a lot of us understood that the system was already under pressure.” He said In the NASA oral history, “But that’s what we signed up to do.”
When the opportunity arose for another trip, Dr. Cliff did not hesitate. She was selected as a specialist for the Atlantis mission in May 1989 that successfully deployed the Magellan probe to Venus. Magellan went on to map more than 95% of the planet’s surface and take measurements of its extremely hot atmosphere.
During Atlantis’ orbits, Dr. Cliff often looked at patches of farmland and other deforested gaps in the vast Amazon rainforest. She made a decision during the mission that she would return to environmental research, the heart of her studies before entering NASA in 1980.
“The amount of deforestation that I was able to see, just in the five years between my spaceflights there, scared the hell out of me,” she said. Tell Orlando Sentinel earlier this year.
Dr. Cliff moved on to NASA projects related to climate and the environment, leading studies that used satellites to track the ocean environment, such as levels of phytoplankton and other plant life. The data provided more evidence about the effects of a warming planet on the food chain and overall ocean health.
In her lectures, Dr. Cliff gave audiences a glimpse of her self-deprecating wit and a heavy dose of frank urgency.
“I’ve been able to study green slime on a global scale,” she told the Society of Geoscientists at a meeting at Snowbird Resort in Utah in 1997.
She added that the pace and scale of disruptions to ocean and environmental patterns caused by climate change due to human activity is irrefutable. “Bubble! It kills fish, with no food and less oxygen,” she said, describing cycles of warming in the Pacific Ocean known as El Niño and its impact on ocean life and monsoon-like storms. “And you guys are going to kayak on Main Street in Salt Lake.”
Dr. Cliff said she saw the space shuttle missions as part of the critical science to assess the effects of climate change and other human-caused environmental crises such as those involving the leakage of agricultural pesticides and fertilizers into waterways.
“Collecting space data is the only way we can find out everything,” she once said.
“Too short” for airlines
Mary Louise Cliffe was born in Southampton, New York, on February 5, 1947, and grew up in another Long Island community, Great Neck. Her father was a music teacher, and her mother taught special education. They have also operated a summer camp on Lake Champlain for 20 years.
She began taking flying lessons on Long Island at the age of 14, using money she earned from babysitting. She thought about becoming a flight attendant. “But I was too short,” she told the New York Times. “In those days, you had to be 5 feet 4 inches tall and I’m only 5-2.”
Then I applied to Cornell University College of Veterinary Medicine. At that time, women were not accepted. “They used to discriminate based on gender in all vocational schools,” she said.
She earned her bachelor’s degree in biology from Colorado State University in 1969 and her master’s degree in microbial ecology in 1975 from Utah State University, where she also completed her doctorate in civil and environmental engineering in 1979.
One day, a colleague asked her to review a NASA notice at the post office that was looking for engineers to train astronauts.
“He said, ‘You’re the only engineering student I know who’s crazy enough to do this,'” she told Newsday.
“You’re right,” I said.
On her first Space Shuttle mission, in late 1985, Dr. Cliffe was an aerospace engineer and operated a robotic arm used by other crew members during spacewalks to test construction methods for building a space station.
She was also assigned an emergency mission to fix a malfunctioning Atlantis toilet, she told NASA oral history interviewer Rebecca Wright.
“Sir, I am used to working on the other end of the pipe,” she recounted her comments to the control center, referring to her previous work in water and environment.
“That must be how I got the title of ‘first space plumber,’” Wright said.
“Yes,” said Dr. Cliff, laughing. “Or the ‘health fairy.’”
Dr. Cliff retired from NASA in 2007 as Associate Administrator of NASA’s Science Mission Directorate, based in Washington. She later mentored students through the Astronaut Scholarship Foundation, which provides… Scholarships For STEM students.
Survivors include two sisters.
Before Dr. Cliff’s second mission to Atlantis, I asked mission specialist Mark C. Lee where he wanted to sit during the launch. This was his first time on a space shuttle, and Dr. Cliff wanted to give him a choice: one of the four places on the flight deck or the only space reserved for the lower level. Dr. Cliff was initially disappointed when Lee chose the flight deck.
“I thought it was a really lousy deal. I would be alone up there and not be able to see anything,” she said in an interview with NASA.
To her surprise, she loved it. “I could have screamed. I could have had a great time, man, this is a ride,” she said.
“Extreme travel lover. Bacon fanatic. Troublemaker. Introvert. Passionate music fanatic.”