In the 1980s, astronaut Mary Cleave flew into outer space twice aboard NASA’s space shuttle Atlantis, spending a total of 10 days and 22 hours in space and traveling a total of 3.9 million miles above Earth. Today, she rests at the bottom of the Gulf of Mexico, in an artificial reef cast using a mix of concrete and her cremated remains.

The burial at sea was made possible by Eternal Reefs, a partner organization of Reef Innovations, which manufactures what are known as “reef balls” at a facility located on Central Avenue near downtown Sarasota. Reef balls are Swiss cheese-looking concrete domes that mimic coral reefs and provide habitat for marine animals, helping restore underwater ecosystems around the world.

Cleave died in November 2023 at age 76. Before her death, she had made arrangements for her ashes to be sent to Eternal Reefs because of her love for the sea and her concern about the effect of climate change on coral reefs. The ceremony was intended to take place last fall, but was postponed because of Hurricanes Helene and Milton. So, in March, Cleave’s family gathered in Sarasota to honor her wishes, decorating a reef ball with seashells and other mementos—like Atlantis commemorative coins—and reflecting on her many accomplishments.

“She got her pilot’s license before she got her driver’s license,” Cleave’s sister, Bobbie Cleave, recalled. “She was born an engineer. While I liked dolls, she liked to take the toaster apart just to put it back together.”

Before joining NASA, Cleave earned a bachelor’s degree in biological sciences from Colorado State University and a master’s degree in microbial biology from Utah State University, where she also received a doctorate in civil environmental engineering. A friend pointed out that NASA was recruiting engineers for its shuttle program, and Cleave was quickly accepted into the program. She stayed with the agency for 27 years, 11 of them in the astronaut corps. According to her family, she had no significant ties to Sarasota, but when she came across Eternal Reefs, she was drawn to the concept because of the beauty of Florida’s Gulf Coast.

Eight other families also made arrangements to have their loved ones’ remains cast on the same day as Cleave’s in March. The families decorated different reef balls, each topped with a bronze epitaph. Since a Gulf burial must be coordinated months in advance, families have typically grieved their loss ahead of time, which gives casting days an air of celebration. People who were otherwise strangers traded stories about their loved ones and became friends as they mixed ashes and concrete.

Since Eternal Reefs’ founding in 1998, the company has laid to rest the remains of more than 3,000 people, 1,000 of whom are at a burial site named Silvertooth near Big Pass. As many as four people’s ashes can be cast into a reef ball, at prices ranging from $4,000 to $9,000. Pets can also be included free of charge, and Cleave was buried with her Jack Russell Terrier, Abby, who died one month before she did.

Three days after Cleave’s casting, her family and the others boarded a large ferry to rendezvous with an Eternal Reefs barge anchored about a mile out from Sarasota. There, a crane hoisted each reef ball and lowered it 35 feet to the bottom of the Gulf, while family members tossed flowers in remembrance. After all the reef balls were lowered, someone read a 1962 speech given by President John F. Kennedy that is known as “The Sea,” in a poignant moment of reflection. “We are tied to the ocean,” Kennedy said. “And when we go back to the sea, whether it is to sail or to watch it, we are going back from whence we came.”