Mary Cleave, an astronaut who saw increasingly alarming views of the Earth’s changing environment during two space shuttle missions in the 1980s, prompting her to work in climate research for NASA, died on Nov. 27 at her home in Annapolis, Md. She was 76.
Her nephew Howard Carter said the cause was a stroke.
In 1985, Dr. Cleave, an environmental engineer, flew aboard the Atlantis, helping to operate its robotic arm during other astronauts’ spacewalks. Four years later, she joined a four-day mission on the same spacecraft when it sent the Magellan robotic space probe to Venus to map the planet’s surface.
What she saw from the shuttle informed her view of a rapidly deteriorating world.
“Looking at the Earth,” she told the Annapolis newspaper The Capital this year, “particularly the Amazon rainforest, the amount of deforestation I could see, just in the five years between my two spaceflights down there, scared the hell out of me.”
And she saw other changes, she told a NASA oral history interviewer in 2002.
“Cities were gray smudges; the gray smudges were getting bigger,” she said. “The air looked dirtier, less trees, more roads, all those things.”
After retiring as an astronaut in 1991, Dr. Cleave transferred to the Goddard Space Flight Center in Greenbelt, Md. There, she managed a $43-million project that used a satellite sensor to collect ocean data showing the impact of global warming, in particular by measuring the abundance and distribution of phytoplankton. These microscopic plants and algae convert carbon dioxide into their cellular material and provide the basis of the marine food chain while producing oxygen.
“I get to study green slime on a global basis,” she said in a speech to the Association for Women Geoscientists in 1997.
It was something of a return to her undergraduate studies in biological sciences at Colorado State University.
“My botany professor told me that lower plants are what make the world go ’round, and I think he was right,” she said in a 2020 interview with the NASA International Space Apps Challenge, an event for coders, scientists and other innovators to use open data from the space agency to find solutions to problems on Earth and in space.
“I got recruited into engineering because of my ability to work with lower plants, which is a little bit backwards,” she added. “And it worked out really well for me.”
Mary Louise Cleave was born on Feb. 5, 1947, in Southampton, N.Y., and grew up in Great Neck, also on Long Island. Her mother, Barbara (Toy) Cleave, was a special-education teacher. Her father, Howard, taught band music. Her parents also owned a summer camp.
Mary built model airplanes as a child and at 14 used her babysitting money for flying lessons. She said she soloed at 16 and earned her pilot’s license a year later. She thought about becoming a flight attendant, she said, but was too short to meet the height requirement.
She earned a bachelor’s degree from Colorado State in 1969 and attended Utah State University for postgraduate work, earning a master’s in microbial ecology in 1973 and a Ph.D. in civil and environmental engineering in 1979.
While finishing her doctorate, she was working at the Utah Water Research Laboratory in Logan when a co-worker told her about a notice that NASA had put up in a local post soliciting scientists and engineers to join the shuttle program, which had not yet sent its first mission into space.
“He came back to the lab and he said, ‘You’re the only engineer I know that’s crazy enough to want to do something like that,’” she said in the oral history, “because I was always liking to do crazy things, ski too fast, among other things.”
She was chosen for the shuttle program in 1980. Her assignments including helping to design a better toilet for the craft and serving as a Mission Control communicator with the crew of the Challenger in 1983, a flight in which Sally Ride became the first American woman in space.
In late 1985, with Dr. Cleave aboard the Atlantis, the spacecraft released three satellites into orbit. She did organic crystal growth tests for the 3M company and created an inadvertently memorable moment when she dumped wastewater from the shuttle at sunset while flying high over Houston, with the sun illuminating the shuttle; the resulting stream stretched for 15 miles and was named “Cleave’s Comet” by Dr. Ride, the Mission Control communicator for that flight.
In late January 1986, the Challenger exploded 73 seconds after takeoff, killing its seven crew members, including the two women aboard, Christa McAuliffe and Judith Resnik. When shuttle missions resumed in 1988, the first three flights had all-male crews until Dr. Cleave was chosen to ride the Atlantis again.
She said that the mission, which was best known for deploying the Magellan, was a breeze compared with her first one.
“First day, it’s out of there,” she said in the NASA oral history. “Then we had three days. So that flight I got to do a lot more picture-taking.”
After her service in the astronaut corps and at the Goddard Space Flight Center, Dr. Cleave moved to Washington, D.C., in 2000 to be NASA’s deputy associate administrator for advanced planning in the Office of Earth Science. As the associate administrator for NASA’s Science Mission Directorate from 2005 until she retired in 2007, she oversaw research and scientific programs concerning the Earth, the solar system and the universe.
“Mary was a force of nature with a passion for science, exploration and caring for our home planet,” Bob Cabana, NASA’s associate administrator, said in a statement.
She is survived by her sisters, Bobbie Cleave and Gertrude Carter.
Dr. Cleave was assigned to a third shuttle flight, on the Columbia, but decided not to go; she had been anxious to start her environmental work, she said.
She told the oral history that “the more I thought about it, the more it bothered me how fast the Earth is changing.”
“I mean, only four years and I was looking down and there were just huge changes,” she said. adding, “That’s really not time at all.”
