Dr. Mary Cleave was a pilot, an environmental engineer, and one of the NASA’s first female astronauts. Her name may not be well known, but she did remarkable work for NASA – both in space and here on planet Earth.
An environmental engineer aboard the shuttle Atlantis, operating its robotic arm during other astronauts’ space walks, she later joined a four-day mission on the same aircraft, sending the Magellan robotic space probe to Venus to map its surface.
A Dire Overview Effect
It’s not uncommon for astronauts to experience what they call the “overview effect” – seeing Earth as a gleaming planet suspended in darkness, an oasis of life in a silent void, that fills them with awe. But Dr. Cleave’s overview effect was marked by fear and a sense of urgency as she focused her attention on what she saw as growing crisis below her – the steady deterioration of planet Earth.
In an interview with Annapolis’ newspaper The Capital, she said, “looking at the Earth, particularly the Amazon rainforest and amount of deforestation I could see, just in the five years between my two spaceflights, scared the hell out of me.” But that wasn’t all she saw.
She described what she saw during her two shuttle missions as “catastrophic.” As part of a 2002 NASA oral history interview, she described how the cities over which Atlantis orbited “were gray smudges; and those gray smudges were getting bigger. The air looked dirtier, with fewer trees, more roads, all those things.”
It was from the silent vastness of space that Dr. Mary Cleave realized her true calling was not to reach for the stars, but to return to Earth and help save it.
Early Life
Born in 1947 in New York and raised on Long Island, young Mary Cleave built model airplanes and, at age 14, used her babysitting money for flying lessons. She flew solo at 16 and earned her pilot’s license a year later – even before she got her driver’s license. She briefly thought about becoming a flight attendant until realizing that, at 5’ 2”, she couldn’t meet the height requirement.
Education
Cleave earned her bachelor’s degree in Biological Sciences from Colorado State in 1969. She completed her postgraduate work at Utah State University, where she earned a master’s in Microbial Ecology in 1973 and received her Ph.D. in Civil and Environmental Engineering in 1979.
NASA Shuttle Years
It was while finishing her doctorate, working at the Utah Water Research Laboratory, that a co-worker shared a notice from NASA soliciting scientists and engineers to join the shuttle program, which had yet to launch its first mission into space. She recalled, “he came back to the lab and said, ‘you’re the only engineer I know who’s crazy enough to want to do this’.” Dr. Cleave was chosen for the shuttle program in 1980. One of her first duties was fixing a malfunctioning toilet in the shuttle Atlantis, leading to her being known as the “first space plumber.”
She served as a Mission Control Communicator with the crew of the Challenger in 1983 – the flight in which Sally Ride became the first woman in space. When Cleave spoke to Ride in orbit, it was the first female-to-female space communication in the agency’s history.
Two years later, Dr. Cleave had another memorable moment aboard the Atlantis as the shuttle passed over Houston at sunset. NASA had alerted the public this would be a particularly good time to see the shuttle, with the sun’s rays illuminating Atlantis like a bright star.
As luck would have it, a wastewater dump was scheduled for the same time, which was also illuminated for all those eager eyes to the skies. As Mission Control Communicator Dr. Ride told the shuttle crew, “people saw both the shuttle and the dump. The stream appeared to be about 15 miles long and was very bright. We’re calling it “Cleave’s comet.”
It was in late 1986 when the Challenger exploded just 73 seconds after launch, killing its seven crew members, including 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.
Goddard Years
Dr. Cleave retired from her role as an astronaut, transferring to the Goddard Space Flight Center in Greenbelt, MD, in 1991. There, she managed a $43-million NASA-funded project using satellite sensors to collect ocean data on the impact of global warming by measuring the abundance and distribution patterns of phytoplankton.
Most of us don’t give much thought to phytoplankton, but these microscopic plants convert carbon dioxide into their cellular makeup and provide the basis of the marine food chain while, at the same time, producing oxygen. Dr. Cleave summed up her work in a 1997 speech to the Association for Women Geoscientists in Utah by saying, “I get to study green slime on a global basis.”
Combining self-deprecating wit with blunt urgency, she also noted that the pace and scale of disruptions in ocean patterns and ecology caused by human-triggered climate change were irrefutable. “Boom! You get fish kills – no food and less oxygen,” she said in describing the Pacific warming cycle known as El Niño and its effect on ocean life and monsoon-like storms.
Oxygen-depleting hypoxic – or “dead”— zones occur naturally, but they’re made worse by human activity. Excess nutrients that run off land or are piped as wastewater into rivers and off our coasts stimulate algae growth, which then sinks and decomposes. The process of decomposition consumes oxygen and depletes the supply available to maintain healthy marine life.
She saw her move to Goddard as a throwback of sorts to her undergraduate studies in biological sciences at Colorado State University, where a botany professor once told her it was those lower plants that made the world go ‘round.
Post-Goddard Years and Retirement
After leaving Goddard in 2000, she moved to Washington, DC, to become NASA’s Deputy Associate Administrator for Planning in its Office of Earth Science. For two years, from 2005 until her retirement in 2007, she oversaw research and scientific programs focused on the Earth, solar system and universe.
When she was assigned to a third shuttle flight on the Columbia, Dr. Cleave opted not to go. She was anxious to start her environmental work. As she told interviewers for NASA’s 2002 oral history project, “the more I thought about it, the more it bothered me how fast the Earth was changing. I mean, in only four years, I was looking down from above on what were huge changes. And that’s really no time at all.”
She retired from NASA in 2007, devoting herself to volunteer work and encouraging young women to pursue interests in science and engineering. She also mentored NASA’s Astronaut Scholarship Foundation, supporting the best and brightest STEM scholars while honoring the legacy of America’s pioneering astronauts with 50 scholarships valued at up to $15,000 to each selected scholar.
Wordwide “Call to Earth”
In 2015, astronauts from around the world contributed to a video titled “Call to Earth,” urging world leaders to act ahead of the Paris Agreement. Their plea? If we don’t clean up our act, and fast, we could irreversibly destroy the only home we’ve got.
Mary Cleave: “It’s amazing how fragile the atmosphere looks from space. All we have is a thin film of air to protect us from the terrible vacuum of outer space. It is quite literally part of our life support system. We need to be really careful with it.”
Michael López-Alegría, astronaut: “Those of us lucky enough to have orbited the Earth have not only heard about the negative impact the industrial age has had on our planet; we’ve seen it with our own eyes.”
Ernst Messerschmid, German astronaut: “We have witnessed the shrinking of the Aral Sea, burning rainforests along the Amazon and in Indonesia, the polluted air over industrial zones, and the dirty water at the river deltas.”
Wubbo Ockels, Dutch astronaut: “When you have the spirit and insight and attitude of an astronaut, you start to love the Earth. And when you love something, you don’t want to lose it. Our Earth has cancer. I have cancer, too.” Mr. Ockels died the day after he recorded his message for the video.
Awards and Honors
Long considered a role model in science and space exploration, Dr. Cleave is the recipient of various honors. They include the American Astronautical Society Neil Armstrong Flight Achievement Award (1989); the NASA Exceptional Achievement Medal (1994); and being profiled along with Sally Ride, Anna Fisher, and America’s other women astronauts in the Women in Space DVD (2004) and the original Women’s Adventures in Science book series published by the National Academies Press.
When Dr. Mary Cleave suffered a stroke and died in Annapolis in November of 2023 at the age of 76, NASA Associate Administrator Bob Cabana remembered her as a trail blazer and “a force of nature with a passion for science, exploration, and caring for our home planet.”
She was also a fervent admirer of the late astrophysicist Dr. Carl Sagan, who captured millions of imaginations with his 1980-1981 television series Cosmos and his Pale Blue Dot prose, contending his video (link below) was the only argument that made conservation and sustainability everybody’s responsibility on the planet we all call home, appealing to “both the intellect and the emotions in a way nothing before had.”
