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NASA’s Incredible Neutral Buoyancy Lab


Written by: Robbie Hadley


            Space, the final frontier. Despite being written nearly 60 years ago for the original series of Star Trek, it is as much the truth now as ever. Humans have dived to the very deepest parts of the ocean, scoured nearly every single inch of the open ocean, and occupied practically every corner of our terrestrial planet. However, space has been a continual roadblock to continuing our expansion.

            The reason for this is extremely simple. Space is dangerous. Humans have spent the last several hundred thousand years evolving to become the apex predators of the planet. We can survive the harsh cold, the scorching heat, and everywhere in between, but none of that Darwinian process gave us the kind of preparation we would need to survive in the vacuum of space.

Despite the inconceivable difficulties, there was one thing that the hundreds of millenia did give us, which is our ingenuity. Space is not just the final frontier but also the greatest challenge for us to overcome. Even the gargantuan task of climate change is just one part of the solutions required for us to live in space or on other planets long term.

 With all of that though, humans have achieved enough that it is truly mind boggling. From the James Webb and Hubble Telescopes, to the multiple missions to Mars, and of course, the Apollo program, humans have looked at the stars as a challenge and as many times as not, have come out successful.

The National Aeronautics and Space Administration, known the world over as NASA, has been on the forefront of these innovations from the very beginning. With the might and nearly bottomless pockets of the American government behind them, they have cleared obstacles that were thought impossible. This is because NASA does not accept defeat. Legendary flight director Gene Kranz is said to have been the first to utter the phrase which NASA now claims as one of its mottos. “Failure is not an option.”

In order to work in a no failure environment, NASA goes out of its way to make sure that every single eventuality is discussed, covered, and trained upon. It is this training that allows astronauts to complete their missions even when the odds are stacked against them.

Of the many different techniques devised to prepare astronauts for their extraterrestrial careers, almost none are more ingeniously simple than the Neutral Buoyancy Lab, or NBL. The NBL takes the physics of swimming and buoyancy and utilizes them to simulate the conditions of microgravity that astronauts will experience in space. Although the facility itself is relatively simple, at least in comparison to landing a man on the moon, teams of people work around the clock to make sure that these men and women working in space have the best chance possible to complete their missions successfully.


Gravitational and Space Suit Training

            For as long as there have been Astronauts, NASA has been trying their best to prepare them for the dangers of space, both known and unknown. In the earliest days they were simply training them to survive a trip in a rocket and back to Earth, so they hired Air Force test pilots with experience in dangerous, experimental machines going at incredible speeds and at high gravitational forces.

            As their missions evolved, they needed more than just someone with The Right Stuff physically, but they also had to be competent scientists ready to conduct experiments and problem solve in this new environment. However, despite all of these new changes, one of the core issues was the same. Astronauts absolutely must be able to cope with extreme changes in gravitational forces during the course of their missions.

            Let’s take a second to look at gravitational forces and their effects on the human body as it will be important to understanding how all of these technologies are important to astronaut training. Large clumps of matter, say a planet like Earth, are massive enough to bend space around them and drag any nearby objects to them. This, along with the movement of the planets with the solar system and the galaxy is how we are able to stay in incredibly predictable orbits. We describe the effect of the Earth’s gravitational pull as one gravity, or 1G. Other astral bodies such as the Moon or Mars will have much less gravity while larger ones will have much more. We measure them all in terms of Earth’s gravity, so when we say that Jupiter has 2.54 G’s, we mean that its gravitational pull is 2.54 times stronger than Earth’s.

            As you move away from these large chunks of matter, their gravitational forces diminish significantly. Astronauts on the International Space Station, ISS, experience weightlessness, although this is from the fact that the ISS’s orbit around the Earth means that it is constantly in free fall. Nomatter what the cause, this low gravity environment is among the most famous effects of space and also one of the most difficult to adapt to. Those countless millennia of evolution always assumed our feet would be firmly on the ground and being in zero-G is therefore extremely difficult to adapt to. Basic body systems like the vestibular system which controls core functions equilibrium go completely haywire.

            This is hard to cope with in any circumstance. Even while within their tightly controlled habitats, everything from dinnertime to going to the bathroom have to be modified significantly to deal with these challenges. The difficulties are multiplied on spacewalks when the bulky space suits are added to everything.

            Just being able to use these space suits, known officially as Extravehicular Mobility Units or EMUs, requires extensive training. One of the key places that astronauts train is in lava beds of Central Oregon. This terrain allows them to get a feel for the ground and landscape that is remarkably similar to that which is on the moon. However, this training does have one enormous drawback. It is in 1G. For the nearly entire time that astronauts are in their EMUs in space, they will be under the effects of microgravity but Oregon, like the rest of the planet, is stuck at a stubborn 1G.

            The first attempt at training at simulated zero-G was very clever, but had a number of drawbacks. For the Gemini mission, astronauts were sent up in planes on parabolic flight plans. Basically, the plane would fly down at a sharp angle allowing the passengers inside to fall, simulating the effects of being in microgravity, but this was only achievable for about thirty second stents before the plane would have to arc back up, ending the effect. This meant that their training had to fit into these thirty second bursts. This was deemed far too inefficient and by 1966 it was determined that a new training method needed to be devised.

To get training in an environment that simulated zero-G for extended lengths of time, a simple but brilliant solution was devised. Throw the astronauts in a pool. We certainly do not have the time to get into the intricacies of hydrodynamics, it is often considered one of the most difficult branches of physical science, but if a person is made to have neutral buoyancy, meaning that they neither sink nor float, the sensation is incredibly similar to that experienced when an astronaut is in microgravity. Also, the EMUs were already completely airtight and waterproof to withstand the vacuum of space, so they needed little modification to be used in pools, adding to the realism of the training.

            By early 1967, NASA had finished the Water Immersion Facility at Johnson Space Center in Houston, TX. This was the first failicy that allowed astronauts to work underwater. At 7.5 meters wide and less than 5 meters deep, it wasn’t exactly an Olympic sized swimming pool. Your neighbor’s above ground pool probably isn’t that much smaller than this, but it got the job done. Neil Armstrong and Buzz Aldrin both trained in this pool for the legendary Apollo 11 mission that saw man set foot on the moon for the first time.

            Eventually though, the WIF’s miniscule size started to be a hindrance. Even before Armstrong set foot on the moon, NASA was planning on a larger facility to train astronauts for the Skylab space station. At this point, they moved to the Neutral Buoyancy Simulator in Huntsville, AL. At just over 12 meters deep, this allowed for a wider range of training and even saw some collaborative training between astronauts and Russian Cosmonauts, but its distance away from mission control and the bulk of training in Houston meant that this was an imperfect solution.

            Yet another facility, The Weightless Environment Training Facility was built back at Johnson and opened in 1980 in time to start training astronauts for the shuttle program. Although not as large as the Neutral Buoyancy Simulator at only 7.5 meters deep, the convenience of having it near other training facilities made it the go-to for nearly twenty years. That being said, the Neutral Buoyancy Simulator was still used infrequently through the 90’s as a secondary training location.

            Once again, NASA kept running into the same problem it had been butting up against since 1967. The pool was too damn small. With construction and training of the ISS in full swing, NASA wanted a facility that could house entire sections of the station submerged within it so that the astronauts could train with full analogs of the actual facility in a simulated zero-G. At this point, they wanted a future proof solution that was big enough to handle basically anything that they could throw at it.


Building Buoyancy

            It was decided that Johnson Space Center needed to expand. Among the many reasons given for this decision was the building of the Neutral Buoyancy Lab, which was to be a long term solution to the issue of training in simulated zero-G. Building on land a few miles north of the main facility, the foundation for the NBL was laid. It dwarfed all of the previous facilities at 62 meters in length, 31 meters in width, and 12 meters deep, holding 23.5 million liters of water. Construction started in 1995 and ended in 1997. Unlike most Megaprojects, this one seems to have to come in on time and budget. That is probably because the construction of this facility, although interesting, was not particularly difficult. There were hundreds of thousands of pools in Texas alone, and this was hardly different, just much, much bigger.

            For reference, the NBL just barely makes it into the top 20 largest pools in the world with the largest, the Citystars Pool in Sharm El Sheikh, Egypt, is over 50 times larger than the NBL, blurring the line between pool and man made lake. Even within the US it is only the 10th largest. However, it does have many specialized features that separate the NBL from your standard resort pool or even the Olympic swimming pools. For one, the NBL is decked out with all of the top of the line technology needed to train the next generation of extraterrestrial scientists and explorers. With the Artemis mission aiming to send people back to the moon and beyond, the NBL is needed now more than ever.

            Two massive overhead cranes are constantly at work lifting huge, one to one sized, mock ups of whatever it is the astronauts need to be training on. Will they be stationed on the ISS? There are multiple different sections of the station ready to be dropped in. Does the Hubble Telescope need a quick repair? They have a spare one to practice on. Are SpaceEx subcontractors working on the Falcon 9 or the Dragon capsule? Replicas are on hand for whatever it is that they need. There were even full scale replicas of the shuttles until the program was retired in 2011. There are also cranes to lift the astronauts in full gear in and out of the pool.


            Another interesting feature is full workup of closed circuit television cameras. Although this was significantly more impressive in 1997 when the NBL was first opened, there are countless cameras around to see everything that the astronauts are doing. They also have suit mounted cameras that allow them to record them as they are working. Just like an athlete will go back and review footage from previous games to try and find areas of improvement, the astronauts and their teams will do the same to try and iron out any issues that they might have. In space, time is money, and small screw ups can cost millions of dollars. Much more importantly than the financial implications, their lives are all hanging by a thread, quite literally during spacewalks, and mistakes can be incredibly deadly. Luckily for all involved, practice makes perfect, which is exactly what they are banking on.

            On top of all of that, the water is very carefully monitored and controlled. The temperature is always kept between 28 and 31 degrees centigrade to make sure that the support divers don’t suffer from the effects of hypothermia in the water. (The Astronauts’ EMUs are temperature controlled so they don’t have to worry about this.) Also, like most pools, a series of chemicals are added to keep the water sterile, safe, and ready for training at any time. Most impressively, all of the water in the pool is cycled through every 19.6 hours so that the water never stagnates in the pool too long.

            Lastly, there are extensive medical facilities on the premises just in case of an accident. Although injuries in the lab are infrequent at worst, they are ready for just about anything that could be thrown at them. There is even a hyperbaric chamber in case anyone on premises would suffer from decompression sickness. If you want to know more about that, check out our post on Saturation Diving which covers the topic broadly.

The NBL can be seen as one of the great training successes of NASA. From a tiny pool hardly large enough to fit the astronauts to one of the largest and most technologically advanced facilities in the world, neutral buoyancy training has come a very long way. At this point, the NBL has operated for nearly a quarter of a century and is still going strong. NASA astronauts as well as foreign guests and private contractors all use this incredible facility to turn civilians with The Right Stuff into the astronauts and explorers uncovering the secrets of the universe!

We have covered a ton of the topics in today’s post in the past, so if you like this, you should definitely check out our posts on the James Webb Telescope, Hubble, the Mars rovers, the Artemis Program, the ISS, Skylab, and much more. You could do a whole Megaprojects in Space binge watch which we wholeheartedly recommend.

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