Aneutral buoyancy pool orneutral buoyancy tank is a pool of water in whichneutral buoyancy is used totrain astronauts forextravehicular activity and the development of procedures. These pools began to be used in the 1960s and were initially just recreationalswimming pools; dedicated facilities would later be built.
Prior to May 1960, NASA recognized the possibility of underwater neutral buoyancy simulations, and began testing their efficacy. NASA engaged Environmental Research Associates, a company based inBaltimore, to try neutral buoyancy simulations first in a pool nearLangley Research Center. Visitors and other issues disturbed those efforts, so they moved the operation to a swimming pool at theMcDonogh School in Maryland, whereScott Carpenter was the first astronaut to participatesuited. Then, after difficultEVAs throughGemini 11 in mid-September 1966, the Manned Spacecraft Center (later renamed theJohnson Space Center) fully understood the importance of testing procedures underwater, and sent theGemini 12 crew to train at McDonogh.[1][2][3][4]
The Neutral Buoyancy Simulator, located at theMarshall Spaceflight Center in Alabama, operated from 1967 through 1997.[5] The facility had three tanks. The first had a diameter of 2.4 meters (8 ft) and a depth of 2.4 meters (8 ft). The second tank was built in 1966 and had a diameter of 7.6 meters (25 ft) and a depth of 4.6 meters (15 ft). A third tank was added around 1968 for Skylab and other planned projects; it had a diameter of 23 meters (75 ft) and was 12 meters (40 ft) deep.
Training in the NBS decreased when the Johnson Space Center opened its own neutral buoyancy pool in 1980, it eventually was closed in 1997.[5]
WIF was used for the Gemini and Apollo programs and was located in Building 5 at the Johnson Space Center in Houston, Texas.
The pool had a diameter of 7.6 meters (25 ft) and a depth of 4.9 meters (16 ft).
WETF, in operation from 1980 through 1998, was located in Building 29 at the Johnson Space Center in Houston, Texas.[5][6] The dimensions of the pool were 24 meters (78 ft) by 10 meters (33 ft), with a depth of 7.6 meters (25 ft).[6]
In the late 1980s, NASA began to consider replacing the WETF, which was too small to hold useful mock-ups of many of the space station components planned forSpace StationFreedom, which later morphed into theInternational Space Station. NASA purchased the then-processing facility fromMcDonnell Douglas in the early 1990s, and began refitting it as a neutral-buoyancy training center in 1994 with construction ending in December 1995. The NBL began operation in 1997.[7]
The NBL is located at theSonny Carter Training Facility, near theJohnson Space Center in Houston.[8] The pool's dimensions are 62 meters (202 ft) by 31 meters (102 ft), with a depth of 12 meters (40 ft).[8]
Following theVoskhod 2 mission, a group at theGagarin Cosmonaut Training Center (GCTC) proposed training for EVAs in a pool.[9] In September 1969, GCTC created a working group to further study the idea, and some experiments were performed in their swimming pool near the end of that year.[9] In 1970, cosmonautsAndriyan Nikolayev andVitaly Sevastyanov visited NASA's new 23 meters (75 ft)-diameter pool at Marshall.[9] Sevastyanov was even allowed to don a training suit and enter the pool.[9] Following the visit, further interest in a similar facility began to grow within the Soviet space program.[9] In November 1973, it was officially decided to construct a dedicated pool; until then, the center's swimming pool continued to be used.[9]
Hydro Lab was completed in early 1980; the pool there has a diameter of 23 meters (75 ft) and a depth of 12 meters (39 ft).[9][10]
The Chinese NBF[11] is located at the China Astronaut Research and Training Center in Beijing. It has a diameter of 23 meters (75 ft) and depth of 10 meters (33 ft).[12] Construction began in 2005 and was completed in November 2007.[13] Operations began in 2008.[13]
The European NBF is located at theEuropean Astronaut Center in Cologne, Germany.[14] It has anoctagonal shape and dimensions of 22 meters (72 ft) by 17 meters (56 ft), with a depth of 10 meters (33 ft).[15] Operations began in 2002.[16]
WETS was located at theTsukuba Space Center in Ibaraki, Japan.[5] It opened in 1997 and closed in 2011 due to extensive earthquake damage.[5] The pool had a diameter of 16 meters (52 ft), and depth of 10.5 meters (34 ft).[17]
The NBRF is located at theUniversity of Maryland in the US.[18] The pool has a diameter of 15 meters (50 ft) and a depth of 7.6 meters (25 ft).[18] It was built in 1992, and is the only neutral buoyancy facility on a university campus.[18] The NBRF is part of theSpace Systems Laboratory (SSL) which was originally located at theMassachusetts Institute of Technology (MIT).[18] It split from MIT when the SSL was awarded a grant from NASA to build a dedicated neutral buoyancy pool.[18] Since there was not enough space at MIT for the pool, it was decided to move the SSL to the University of Maryland.[18]
The UAT is located at theUnited States Space and Rocket Center, home ofSpace Camp and Space Academy, in Huntsville, AL. 30 feet wide and 24 feet deep, it was designed byHomer Hickam, a NASA engineer famous for writingRocket Boys, adapted into the filmOctober Sky. Opened in 1986, it is still active.[19]
During training exercises, neutral-buoyancy diving is used to simulate theweightlessness of space travel. To achieve this effect, suited astronauts or pieces of equipment are lowered into the pool using anoverhead crane and then weighted in the water by support divers so that they experience minimalbuoyant force and minimalrotational moment about theircenter of mass.[20] The suits worn by trainees in the NBL are down-rated from fully flight-ratedEMU suits like those in use on the Space Shuttle and International Space Station. Divers breathenitrox while working in the tank.[21][22]
One disadvantage of neutral-buoyancy diving as a simulation of microgravity is the significant amount ofdrag created by the water.[23] This makes it difficult to set an object in motion, and difficult to keep it in motion. It also makes it easier to keep the object stationary. This effect is the opposite of what is experienced in space, where it is easy to set an object in motion, but very difficult to keep it still. Generally, drag effects are minimized by doing tasks slowly in the water. Another downside of neutral buoyancy simulation is that astronauts are not weightlesswithin their suits, meaning that as divers tilt their suits they are pressed against whatever inside surface is facing down. This can be uncomfortable in certain orientations, such as heads-down. Thus, precise suit sizing is critical.
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.
China operates the Neutral Buoyancy Facility at the Astronaut Center of China
