Living underwater isn’t something most people get to do. Mark Hulsbeck has done it. A lot.
The man known to his colleagues as Otter holds the record for most days living in FIU Aquarius, the world’s only underwater research laboratory. Since 1999, he has been a member of the saturation crew at Aquarius, spending a total of 292 days living underwater throughout 31 missions.
Now, FIU’s real-life Aquaman is retiring, saying goodbye to his home away from home.
“Every time I was in there was the best. It never felt like it was another day at the office,” Hulsbeck said. “I’d try to wake up early before everyone else, make coffee and look out the viewport to watch certain fish eat. I’ve seen lightning storms from the bottom, where you look up and see the lightning flashing at the surface. Sometimes if you’re really close to a passing storm, you can actually hear it.”
He has worked with scientists conducting research along the Conch Reef where Aquarius resides and with military teams training there. When NASA developed its first extreme environment training mission at Aquarius, Hulsbeck was on the Aquarius crew. He’s been there for most of the NASA training missions since, including NEEMO 23, the last mission at Aquarius before COVID-19 struck.
Photo courtesy Jonathan Knaul 
Talking to astronauts on the International Space Station from Aquarius is one of the coolest things Hulsbeck says he’s ever done.
“We live underwater 65 feet and the astronauts are up in the space station flying atop of us,” he said. “Many of them had been to Aquarius before and they’d ask us what we see. We’d tell them there was a Goliath grouper outside our window spotted eagle rays. Then we’d ask them what they were seeing. They’d say, ‘We’re crossing over Russia now. We see Alaska coming into view.’ It was just surreal living underwater and talking to them.”
The now-retired aquanaut has witnessed many changes over the years including the addition of Wi-Fi and cell phones in Aquarius. Down-time used to be spent playing cards and chatting up bunkmates. Technology has cut into the social interactions, he said, but has also allowed aquanauts to stay more connected with people at home.
Prior to joining Aquarius, Hulsbeck served in the United States Navy as well as the National Oceanic and Atmospheric Administration Commissioned Corps. He is a licensed boat captain, master scuba diver trainer and hyperbaric chamber operator. Now that his days living below water are done, Hulsbeck recently relocated to Sebastian, Florida with the hopes of spending more time on the water fishing and maybe even getting a part-time gig captaining eco-tours.
