Swimming with spacemen: training for spacewalks at NASA's giant pool
To do construction 200 miles up, you must first go deep underwater.
by Lee Hutchinson
The Test Director
Enlarge / The array of monitors lining the Test Director control room, allowing the TDs to monitor both the astronauts and the divers underwater.
While Scoville and his TCs are responsible for designing and running the spacewalk portion of a test, there's another group of folks who monitor and manage the NBL facility and infrastructure during a test: the test directors (TDs). They operate in a separate control room and keep tabs on the functional aspects of the simulations, letting the TCs monitor and control the actual tests themselves.
Kurt Otten is the NBL's critical systems manager and one of the facility's TDs. He presides over a stable of systems engineers, each responsible for one of the NBL's critical systems (and, like many of the other folks working around the pool, he's a certified dive master and instructor). These systems include the SSRMS arm fixed to the bottom of the pool, the astronaut life support and cooling water systems, the water treatment system, the video and communication systems in the pool, and several other systems. These engineers work to keep those critical systems operating and available during tests, while the TCs use them to actually conduct the tests.
One notable thing the critical systems engineers control is the plethora of cameras. The NBL pool is fitted extensively with the things: there are 22 pan and tilt cameras throughout the pool in fixed positions, and any number of floating mobile cameras will be operating during a test. The TD control room we met in is dominated by a huge bank of video monitors, so I asked Otten if we could see the camera output for some of them.
He smiled and swept a remote across the wall of monitors; they rippled to life with a happy series of chirps. A few of the monitors were tuned to cable TV channels, but most of the displays showed views of the various pieces of equipment. After staring at the ISS mockups through the surface of the water for a couple of hours, seeing everything from a non-refracted perspective startled me.
"The test director is over the whole test," Otten said. "Everything goes through him or her," he explained. During a test, after the astronauts are fully submerged, the test director passes operational responsibility over to the TCs in the next room. "The TCs are our customers, along with the astronauts....We're making the facility available, we're monitoring all the systems and making sure they're participating and functioning correctly. Any time there's a problem, everything's funneled through the test director."
The TD's control extends to the dive team as well. Each astronaut in the pool has a team of four divers assigned to him or her: two safety divers, one camera diver, and one utility diver. The utility diver is of particular importance, because the utility diver handles the training tools - of which there are two different sets. The astronauts use plastic neutrally buoyant tools to get the "feel" of a motion or operation, but the plastic tools don't actually work. After the astronaut rehearses a particular tool motion, the utility diver will swap out the neutrally buoyant plastic tool with a real, functional tool - it doesn't float like the plastic mock-up, but the astronaut can then perform the operation being tested.
When the actual work has been done, the astronaut will trade the practical tool for the neutrally buoyant plastic mock-up, which they will then re-stow on their suit's mini-workstation (a fancy name for the suit's chest-mounted tool rack).
Kurt Otten stands in front of the test director console, explaining how the NBL runs.
Otten then explained something that hadn't occurred to me - the astronauts themselves breathe the same mix of nitrox as the divers, and their EVA suit's pressure must be carefully regulated in order to counteract the changing water pressure. Pressure in the suit is mechanically regulated to be 4.3 PSI greater than ambient, matching the differential above ambient to which the suits are pressurized in space. However, the pool water imparts an increasing pressure of about 0.5 PSI per foot of depth, so different parts of the astronaut's body are under different amounts of effective pressure. The suit might be at 4.3 PSI at the hips, but the feet are deeper and so might be at about 2 PSI relative to the surrounding water; if the astronaut raises his hands above his head, his gloves might reach almost 6 PSI relative to the water. Astronauts quickly learn to keep their hands below their waists as much as possible in order to keep glove pressure lower so they don't have to squeeze as hard to grip things.
Since the pressure in the suits varies as the astronaut rises and sinks in the water column, the environmental systems vary the flow rate of the gasses to the suit as the pressure changes so that the astronaut can breathe in the appropriate amount of oxygen and exhale the appropriate amount of carbon dioxide. The astronauts aren't wired up with biomonitors before descending into the pool, but the test coordinators do keep tabs on the carbon dioxide output of each astronaut and use those measurements to estimate the astronaut's metabolic rate. From that, the TCs can tell whether an astronaut is working too hard and can re-arrange test activities around the astronaut's level of exertion.
The commercial future
the NBL has played host to survival training and teams testing underwater crane and video systemsAn oddly familiar laundry room smell wafted above the chlorine as Peterman led me down one last hallway, and soon there was an out-of-place sound to match it: the irregular clatter of a clothes dryer. "Oh, yeah, that's part of the commercial operations we've taken on," Peterman said. "Because they're required to wear Nomex...so we've got to constantly wash and dry those clothes." Nomex? My interest was piqued.
To find out more about these commercial operations, I talked with Angie Prince, the NBL's external customer business development manager. She outlined how the NBL earns extra money when the facility is not needed for astronaut training.
"So before, when we were doing station assembly," she began, "this facility was utilized to its top max capacity, training EVA astronauts on how to assemble the station. Now assembly is done, and we're complete with the station. We still need to train our astronauts, but we don't need to train the same volume of astronauts... and because of that, we have excess capacity."
The NBL's size and depth make the pool an extremely desirable property for other companies. NASA has allowed Raytheon, the NBL prime contractor, to go out and bid for external contracts to use the NBL when NASA doesn't have planned activities. Prince is a NASA employee whose role is to represent NASA to the commercial companies. So far, uptake has been promising. As we walked around the pool, we came across a mockup of a helicopter crew cabin, used by oil companies for emergency egress training; across from that sits a huge inflated life raft. These training classes are the reason for the Nomex clothing being washed and dried below.
One end of the NBL is roped off for use by commercial programs. At right is the blue helicopter cabin mock-up used for emergency egress training.
So far, energy companies have been most interested - the NBL has played host not just to survival training, but also to research and development teams and to teams testing out underwater crane and video systems. British Petroleum in particular has been interested in the NBL, testing out remotely operated vehicles (ROVs), plus validating and iterating on their pipeline inspection and repair procedures.
More than simply utilizing unused NBL capacity, the commercial activities draw in revenue and generate cost savings for NASA. "We still get facility utilization fees, but the large cost savings to NASA and the benefit to outside customers is, I have to have a certain amount of staff to run this facility." As she talked, one of the two large overhead cranes began to rumble on its track, moving with surprising swiftness and dragging its shadow across the pool. "Their salary or their wages are covered by this external activity, so they don't cost me - me as the government - as much money."
Prince pointed specifically to the helicopter mockup, noting that on Monday the NBL divers might support an oil and gas customer doing survival training and then on Tuesday might support a NASA ISS training mission. The goal is to find repeat customers who can help "keep the knives sharp," as Prince termed it, keeping the facility's personnel in the groove.
Chris Cassidy is lowered into the NBL pool to start his simulation.
Back on the deck, with Parmitano's comms problem fixed, the dive gets underway again. The staff operates with a calm efficiency. Cassidy gets slowly lowered into the pool's calm surface as his divers hover nearby, ready to unhook him from the platform and move him into position over the truss structure mock-up.
"The one thing I can say about my job and the people I work with is that there's not a lot of people who can do what we do," Knight says, watching Don Smith and others finish their work. Pride is evident in his voice. "This is a very unique job. You can go to another space agency and say, 'Hey, I'm a spacesuit engineer,' and they'll say, 'So? We don't have spacesuits.'"
"It's very rewarding for me every time we bring someone back. Every time somebody goes EVA, they go back in the ship and we bring them back down, it's like kudos to us - we know we did our job," he says. "I had one crewman come back and tell me he had gone out to do an EVA. They had gone to the dark side" - meaning the portion of the ISS in shadow - "and he kind of lost track of where he was, as far as where he was at on the space station. The only way he could find his way back was the numbered handrails they have, and he learned that here. He learned the pattern, the translation path... He said then after he started moving he knew exactly where he was at, all because of the pool."
The feeling at NBL is almost otherworldly. The facility sits within spitting distance of a cluster of Houston neighborhoods, and a bit further away are businesses large and small strung all along the main streets that run throughout Webster and Clear Lake and Friendswood. Yet here, in this large but unassuming building, two spacemen are being lowered by a crane into the world's largest indoor pool to work on a giant mock-up of one of the world's most expensive construction projects.
And beyond the ISS, the commercial future of spaceflight is bright. SpaceX and other companies tackling it haven't yet had much need of the NBL, but as crewed commercial flights become a reality, the facility will play a vital role in preparing people to work in microgravity. NASA's own future plans involve using the NBL for training, but the long lead time until the next set of non-ISS manned missions means that the NBL will need to find more customers to keep its people trained and operating efficiently. One way or another, folks will still dive in the big pool, though after the next few years it's unclear how many of them will regularly be from NASA.
But there are still things to be done in Earth orbit, and the NBL remains the best place to prepare and train the few men and women who ride pillars of fire up into the sky. I focus back on Cassidy and ready my camera to photograph him: astronaut, Naval officer, ten-year Navy SEAL, combat veteran. It's not the 1960s anymore and we recognize that our astronauts are people and not saints, but by any measure this is a brave man who does brave things. Starting in March of 2013, he will spend six months in space on board the ISS as a member of Expedition 35 and Expedition 36.
I hold down the shutter button, stretching out the moment into a series of snapshots. As the water closes over his helmet, Cassidy tosses me a salute and vanishes.
Design, layout, and coding by Aurich Lawson, Lee Aylward, and Jason Marlin
Photographs by Lee Hutchinson, Steven Michael, and NASA
The journey isn't quite over, space cadets! Want to see more behind-the-scenes photographs from our tour of the Neutral Buoyancy Laboratory? Head over to Swimming with spacemen: The image gallery for 46 amazing pictures that we couldn't quite fit into this piece, but that were too good not to share.
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Lee Hutchinson / Lee is the Senior Technology Editor at Ars and oversees gadget, automotive, IT, and culture content. He also knows stuff about enterprise storage, security, and manned space flight. Lee is based in Houston, TX.
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