: Ken reads a 5-star iTunes review from Paula Olivet: “I wish this podcast aired everyday.” This show takes science as a personal, academic and professional venture, which it entirely is. It’s not all pipettes and mice. It’s ambition, and unquenchable thirst for answers. Even when I think the episode subject matter is not for me, I still find myself completely enthralled.”

: Dawn recounts Gernhardt’s educational and professional background: He hold a Bachelor’s degree in Physics from Vanderbilt University and a Master’s degree and Ph.D. in Bioengineering from the University of Pennsylvania. He has been a professional deep sea diver and engineer on projects around world. He was a manager and Vice President of Special Projects for Oceaneering International, and established Oceaneering Space Systems to transfer subsea technology and operational experience to the international space program.

: Ken adds: “His impact on the agency and how we do human space flight is really extensive.”

: Dawn welcomes Mike and Tom to the episode.

: Gernhardt explains his initial interest in diving: “As a four or five-year old I was always going fishing with my dad in Florida. At nine or ten, I was doing scuba diving on a family vacation. I got certified at age 12 and became a dive instructor at 18.” For the first couple of summers after college, he worked as a scuba instructor and boat captain at St. Thomas in the Virgin Islands. Then he got into commercial diving, where he noted the limitations in decompression tables.

: These limitations inspired him to study the physiology and biophysics of diving. In college, he studied physics and math, and was a pre-med major. When he graduated, he wasn’t ready to commit to graduate or medical school, so he worked as a commercial diver.

: Describing his commercial diving experience, he says: “Unlike the more sheltered college environment, here it was like: What can you do in the water at the end of the hose? That really inspired me.”

: The Medical Director of Ocean Systems was C.J. Lambertson, who took him under his wing. Gernhardt decided to go to graduate school at the University of Pennsylvania in order to study with Lambertson. “That turned into a 30-year relationship.”

: “We would generate the new decompression tables, and then I would go out and use them…. We tested them real-time.”

: Lambertson said his ultimate goal was to make the field a laboratory. “In this period of three years, we generated tables that became the Oceaneering standard.” Roughly ten million dives have been done on those tables.

: Dawn calls Lambertson one of the godfathers of diving medicine and asks what it was like to work with him.

: Gernhardt answers: “He was an amazing guy. I started reading his books as an undergraduate. When I then met him for the first time, he looked professorial, older, he had a beard…When you shook his hand, he could squeeze your hand off.” Lambertson was also influential during World War II. “He wrote undersea warfare tactics/strategy that influenced everything, on top of the physiological work he did.”

: Gernhardt adds: “He was a personal friend and father figure. When I was there he would just make the time to sit and talk. He was also a great mentor.” Lambertson read “every word” of Gernhardt’s dissertation. “He was hard on me.”

: Gernhardt explains that Lambertson had been an advisor to NASA for decades and sat on all the review committees. “He was reviewing my work. People at headquarters said that was a conflict of interest. I told them, ‘No one’s going to be harder on me than Dr. Lambertson.’ We kind of fought off the bureaucrats on that and produced stuff that has really enabled the assembly and maintenance of space station.”

: Gernhardt started Oceaneering Space Systems in 1987, where he transferred his sub-sea robotics experience to NASA. He invented the Cryopak, which used liquid oxygen for breathing and cooling to handle issues in micro-gravity. They called it the magnetic intake dewar.

: Of the company, Gernhardt says, “We won a large contract to build a sub-critical liquid oxygen storage system, and we beat out major aerospace contractors. That was exciting for our young company at the time. That transitioned us into the space world.”

: Gernhardt says, “There’s really a lot of synergy between working underwater and working in space, and the design of the task for human and robot compatibility.”

: Gernhardt recalls the aerospace contractors who would go to the shop and think that we were selling atmospheric diving suits that weighed about a ton. “I was selling the concepts, the operational knowledge, the design knowledge, and some of these folks thought they were going to buy a suit from us.”

: His company initially included just him and a secretary. “I hired every commercial diver that I knew, that had gone back and gotten an engineering degree. He combined that with going up to the best universities and interviewing top talent. “We put together this magical combination of seasoned commercial divers and smart as heck MIT and JPL [Jet Propulsion Laboratory at NASA] grads and really did an amazing amount of work.”

: Tom asks him how he gave that all up to become a “worker-bee astronaut.”

: Gernhardt explains that becoming an astronaut had been a lifelong goal of his. “In my early teens, I had already put together that working in space and in sea were similar.” Athletic as well, he had “set the distant goal to be an astronaut.”

: Of his first year on the job (as astronaut), he recalls: “There’s a pile of manuals that go up from the floor past your desk, and you’ve got to learn all this, and then you’ve gotta learn to fly a T-38 jet…and then next thing you know you’re flying in space.”

: Gernhardt says he was different from most astronauts in that his area of academic expertise was directly related to EVA (extravehicular activity.) That allowed him to design tools.

: Gernhardt had invented the body-restraint tether (BRT) for undersea diving that became useful in space, as well.

: Tom describes his experience using the BRT: “It was a dream. It enabled you to scramble anyplace on the space station and then grab onto a handrail with your third arm, which you provided, and that left your hands free. And you could turn your body left, right, in and out, and then you could carry it around just by bending it over your shoulder, and it was out of the way of your other tools. It was a very handy device on the space station.”

: Dawn asks about the similarities between diving and EVA.

: Gernhardt replies: “What’s similar is you’re working in a three-dimensional hostile environment: no air in sea or in space.” Furthermore, the way you think about planning the operation is similar, in terms of A, B and C. But the mechanics are very different: “Underwater we’re not in pressurized suits, so you have more mobility and dexterity. You use your hands to feel, but you also have poor visibility…you tend to use all of your body senses. In EVA you’re in a pressurized suit with a similar inflation pressure as a football or basketball; so, every time you move, you’re fighting that inflation pressure.”

: In space, Gernhardt explains, even though you are “weightless,” you actually are not massless. “You and the suit weigh over 500 pounds in space. If you go fast, you could tumble out of control. My motto was: ‘You cannot go too slow’. Never let your hands get ahead of your brain.”

: Another difference between the ocean depths and space: “In space, you have unlimited visibility. You can see literally millions of miles.”

: Commercial break: STEM-Talk is an educational service of the Florida Institute for Human and Machine Cognition, a not-for-profit research lab pioneering ground-breaking technologies aimed at leveraging human cognition, perception, locomotion and resilience.

: Tom asks about Gernhardt’s first EVA because a few weeks before launch, Gernhardt sustained an injury that might have prevented him from participating.

: Gernhardt tells the story: the mission was delayed a week, so he went on a date in Galveston. It was pouring rain and, after dropping his date off at the Grand Theater, he slipped and dislocated his shoulder while running through the parking lot in the rain.

: “I had a great attitude,” Gernhardt says about his recovery and prospect of missing the mission. “If I can do it, great,” he though. “If not, it’s not about me—it’s about the mission.”

: Gernhardt shares an anecdote about how the doctors okayed him for the mission after he proved that he could get in and out of the space suit. “I was in about as much pain as a human can stand. It was a huge mental focus, but it all worked out.”

: Gernhardt talks about the oxygen prebreathe protocol he developed with his team. Fifty subjects experienced no bends, and very few bubbles.

: Tom says: You can see Mike doing the prebreathe protocol on an Imax movie called “Space Station 3D.” https://www.youtube.com/watch?v=O9X84b9t3Do

: Dawn says she was a research assistant on prebreathe protocol at Duke University with Dr. Vann. She assisted with monitoring of subjects and measuring how much they were bubbling at altitude.

: Gernhardt talks about the in-suit light exercise protocol that saves complexity over other exercise protocols. “We use that routinely on space station, and we’ve never had any bends—we’ve had close to 200 EVAs without any decompression sickness.”

: He is working on developing the details of a Phobos Mission in Mars Orbit planned for the 2030s.

: On those missions, he adds, “We would do excursions in a pressurized excursion vehicle,” another of Gernhardt’s inventions. This is a small cabin with great windows; two people live in it for two weeks at a time. The pressure of that cabin is 8.2 pounds per square inch, with 34 percent oxygen.” It puts us at a much better posture for not having to denitrogenate to avoid decompression sickness.”

: Air-lock operations are not fun, Gernhardt says. Tom compares the compressed feeling to “two hippos in the front seat of a Volkswagen.”

: Gernhardt also invented the work efficiency index: the work time you get outside divided by the overhead it took you to get outside. “On the station we spent about two and a half hours inside for every hour outside, and to me that was crazy.”

: “The whole concept is that we have this cabin that is optimized for viewing and low-overhead EVAs. And we can combine that with different mobility elements.”

: Tom characterizes Phobos as a “low-gravity body; the size of a big city.” He asks Gernhardt: “What advantages do we gain from being around Phobos (or Deimos)?”

: Gernhardt answers that Phobos is “very interesting scientifically. It will tell us about the natural history and evolution of Mars… We can pick up pieces of Mars on the Moon of Mars.”

: “It is so much easier to go to the Moon of Mars than Mars’ surface. Mars it the worst place on solar system to try to land because there’s just enough atmosphere to get you hot, but not enough to slow you down.”

: “By going to Phobos, we develop the infrastructure needed to go to Mars.”

: “Phobos is a stepping stone. Ninety-nine percent of everything we would use to go to Phobos takes us towards Mars’ surface.”

: Gernhardt adds that “Mars is only 9,000 Kilometers from Phobos, so every exploration activity or public outreach event that we do will have Mars looming large over the horizon and keep our focus on where we’re going.”

: “My hope is that we sign up to that [going to Mars sometime in the 2030s] and have a plan that we can close a budget around, and really have a focused exploration effort….”

: Gernhardt’s advice to aspiring astronauts: “Get as much education as you can; do things that you like because, if you like them, you’re going to have a good life; you’re going to be good at them…” Do things, he adds, “that are directed towards being an astronaut, but don’t do things that you don’t like in order to be selected as an astronaut.”

: “Learn to be a team player. It’s not about individual super stars.”

: Dawn thanks Mike.

: Dawn marvels at the overlap in the undersea world and space and Gernhardt’s own seamless transition from undersea to space.

: Ken says: “It’s a smooth transition, and Mike depicted it beautifully. He’s a great guy, and a valued collaborator; in fact, he’s truly a man for all seasons.”

: Dawn and Ken sign off.