One Giant Step


Larry "Harris" Taylor, Ph.D.

This is an electronic reprint and expansion of an article that appeared In Discover Diving, (October, 1992, p.12-13). This material (minus NASA photos) is copyrighted and all rights retained by the author. This article is made available as a service to the diving community by the author and may be distributed for any non-commercial or Not-For-Profit use.  

All rights reserved.

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 After this article appeared, NASA built a much larger facility, the Neutral Buoyancy Lab. 

The only thing larger than this new pool is the dedication of the astronauts and their diver support team. 

"One small step for man; one giant step for mankind" are words that will live forever in the hearts and souls of humanity. Before uttering these historic words, astronaut Neil Armstrong, along with a supporting cast of thousands, spent seemingly infinite hours of practice to insure a safe and successful lunar operation. 

The key to any successful operation is practice. The better the practice in anticipating the reality of a working predicament, the better the task will ultimately be done. The astronauts work in the near zero vacuum and zero gravity outside earth's atmosphere.  Not only must their fragile humanity be protected by bulky environmental suits that isolate the astronaut from the task at hand, but they must learn to function within these suits to perform useful tasks. In space, work tasks that appear trivial on earth, take on a new challenge, as the tasks must be completed without the aid of gravity. Accomplishing useful labor requires special tools and much practice. NASA appears to live by the adage that perfect performance is only derived from lots of perfect practice.

The weightlessness of outer space is best simulated on earth in a water environment. We cannot, of course, eliminate the forces of gravity. We can, however, counter the weight of an object in the water by applying a buoyant force. Likewise, floats can be attached to objects denser than water. This application of an equal opposing force provides an illusion of working in a weightlessness environment. This environment allows astronauts to develop appropriate work skills on earth before attempting a project in the weightless vacuum of their orbital working environment. 

The Weightless Environmental Training Facility (WETF) is housed in building 29 of the Lyndon Johnson Space Center in Houston, Texas. Its purpose is to provide a weightless training environment for the corps of astronauts who will operate in space. This essential facility allows engineers and designers an opportunity to develop spacecraft equipment, to evaluate tools and procedures that allow people to function in space and to safely evaluate human capabilities and workload capacities within the constraints of the environmental protection systems and specialized tools they are using. 


 Astronaut Support/Monitor Consoles                                            Close-Up of Consoles

The actual training now occurs in a 78' x 33' swimming pool that is 25 feet deep. The pool itself appears no different from any other swimming pool. It is filled with water and reeks of chlorine. The surroundings, however, rapidly inform the visitor that this is no ordinary swimming pool. Above the pool are two pneumatic cranes, each capable of lifting more than 5 tons. These devices move full-scale space shuttle and other payload mock-ups designed for work in outer space into the pool. On one side of the pool is a storage area for a vast assortment of these full-scale models. The current pool is not large enough for a complete full-size spacecraft so that astronauts must practice on only the payload bay area. The pool now being used is also too small for practice on the assembly of the planned international joint-venture space station. A planned future facility will be large enough to house complete shuttle and space station mock-ups. Different training missions require different models and the cranes move the relevant mock-ups into and out of the pool. In addition, there are two distinct monitoring stations. The first series of monitoring instrumentation monitors the physiological status of each of the up to two astronauts in the pool during a training mission. NASA policy mandates that physicians with expertise in aerospace medicine be available during all training activities. A second series of monitors continuously evaluates the environmental suits that the astronauts use and the total status of the training mission.  The entire pool is under constant video camera surveillance. The divers will tell you that everything that occurs in the pool during a training mission is being observed topside. Next to this monitoring station is all the plumbing necessary to furnish breathing air and cooling water to the astronaut's environmental suits. Of course, also present is complete back up of all systems.  Lastly, there is a complete diving locker equipped with compressor and storage cylinders to support the dive team of more than 30 divers.

The WETF dive support team is a unique group of divers. They are not mere sport divers.  Each must maintain superb physical fitness and operate at a high level of diving efficiency. Many incoming sport divers must be retrained too much higher standards to operate within WETF working guidelines. Much of the WETF diver's time is spent training to insure this continuous high level of performance. Each must be qualified in astronaut in-pool rescue and must maintain this proficiency by actual demonstration.  This particular rescue involves lifting a diver in a totally flooded environmental space suit from the bottom of the pool to a position where life-support assistance is possible. The exercise must be successfully completed in less than one minute. (Note that moving a flooded space suit around the pool and lifting it 25 feet to the surface is not an easy task.) But, these are not ordinary divers!  They are responsible for the lives of the astronauts during in-water training. 


 Astronaut rides elevator into training area             Note the ratio of divers / astronaut 

Before a training session begins, the divers inspect the training mock-ups and insure that all necessary materials have been assembled and are available to the astronauts. During the training mission, each astronaut is assigned two divers. The training mission begins by insuring that the astronaut and all his/her limbs are neutrally buoyant. This involves a rather elaborate system of weights that are placed at various locations on the environmental protection suit so that astronaut can be truly neutrally buoyant during training. Of course, each astronaut is different physically so that each astronaut's buoyancy must be individually fine-tuned for each training mission. The goal is such that no matter what orientation the astronaut trainee assumes in the pool, neither gravity nor suit buoyancy will control movement. Throughout the training mission the divers, as well as the topside crew, monitor the astronaut. In the unlikely event of a system failure, the divers must instantaneously respond to pull the astronaut out of the water. After the training mission is over, the divers must re-configure the pool and insure that all training mock-ups are ready for the next training mission.


 Astronauts practice single and team tasks on full size mockups

Occasionally, completely new space suit designs are tested in the pool and divers will do some of the actual testing. I suspect that diving in a space suit probably fulfils the ultimate fantasy of everyone who has ever used a dry suit or seen Star Wars and Star Trek. 

It is said that before you can walk, you must first learn to crawl. Before astronauts learn to function in their space environmental protection suits, they must first learn to scuba dive.  So, when the scuba instructors are not watching over the astronauts in their space suits, or maintaining high levels of dive team efficiency, they are teaching new members of the elite corps of astronauts how to scuba dive.  Although no recreational diving certificate is issued as part of this training, the astronauts are trained to NAUI standards

As America leaps into the 21 st. century and prepares to more fully expand humanity's existence in outer space, much of that progress will have been possible because of dedicated WETF divers in a super-sized swimming pool in Houston, Texas.


 The successful completion of NASA in-space missions begins with diver-assisted pool training


The author extends his thanks to the dedicated divers of WETF for sharing with him their unique diving operation. He also extends his appreciation to the administrative staff of the Johnson Space Flight Center for their cooperation in all aspects of the preparation of this article.  

Photo Credits:  

All underwater photos are official NASA photographs used with their permission.

This article is now deposited in the Official NASA historical archives.


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About The Author:

Larry "Harris" Taylor, Ph.D. is a biochemist and Diving Safety Coordinator at the University of Michigan. He has authored more than 100 scuba related articles. His personal dive library (See Alert Diver, Mar/Apr, 1997, p. 54) is considered one of the best recreational sources of information In North America.

  Copyright (minus NASA photos) 2001-2022 by Larry "Harris" Taylor

All rights reserved.

Use of these articles for personal or organizational profit is specifically denied.

These articles may be used for not-for-profit diving education