Joint Airlock
Encyclopedia
The Quest Joint Airlock, previously known as the Joint Airlock Module, is the primary airlock
for the International Space Station
. Quest was designed to host spacewalks
with both Extravehicular Mobility Unit
(EMU) spacesuits and Orlan space suits. The airlock was launched on STS-104
on July 14, 2001. Before Quest was attached, Russia
n spacewalks using Orlan suits could only be done from the Zvezda service module and American
spacewalks using EMUs were only possible when a Space Shuttle
was docked. The arrival of Pirs docking compartment on September 16, 2001 provided another airlock from which Orlan spacewalks can be conducted.
of the Unity
during STS-104
. It has mountings for four high-pressure gas tanks, two containing oxygen
and two containing nitrogen
, which provides for atmospheric replenishment to the American side of the space station, most specifically for the gas lost after a hatch opening during a space walk.
Quest was necessary because American suits will not fit through a Russian airlock hatch and have different components, fittings, and connections. The airlock is designed to contain equipment that can work with both types of spacesuits, however, it is currently only able to host American spacewalks because the equipment necessary to work with Russian space suits has not been launched yet, which required the Expedition 9
crew to take a circuitous route to a worksite because of problems with the American space suits.
in the low pressure, 5 psi (34.5 kPa), pure-oxygen atmosphere of the spacesuit. The previous method of preparing for spacewalks involved breathing pure oxygen for several hours prior to an EVA to purge the body of nitrogen. In April 2006, Expedition 12
Commander Bill McArthur
and Expedition 13
flight engineer Jeffrey Williams tested a new method of preparing for spacewalks by "camping out" or spending the night in the Quest airlock. In the chamber, the pressure was reduced from the normal 14.7 to 10.2 psi (101.4 to 70.3 kPa). Four hours into the Expedition 13 crew's sleep period, an error tone prompted mission controllers to cut short the activity, but the test was still deemed a success. American spacewalk activities thereafter have employed the "camp out" pre-breathing technique.
and tested at NASA
's Marshall Space Flight Center
in Huntsville, Alabama
by the Boeing Company.
Airlock
An airlock is a device which permits the passage of people and objects between a pressure vessel and its surroundings while minimizing the change of pressure in the vessel and loss of air from it...
for the International Space Station
International Space Station
The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...
. Quest was designed to host spacewalks
Extra-vehicular activity
Extra-vehicular activity is work done by an astronaut away from the Earth, and outside of a spacecraft. The term most commonly applies to an EVA made outside a craft orbiting Earth , but also applies to an EVA made on the surface of the Moon...
with both Extravehicular Mobility Unit
Extravehicular Mobility Unit
The Space Shuttle/International Space Station Extravehicular Mobility Unit is an independent anthropomorphic system that provides environmental protection, mobility, life support, and communications for a Space Shuttle or International Space Station crew member to perform extra-vehicular activity...
(EMU) spacesuits and Orlan space suits. The airlock was launched on STS-104
STS-104
STS-104 was a Space Shuttle mission to the International Space Station flown by Space Shuttle Atlantis. Its primary objectives were to install the Quest Joint Airlock and help perform maintenance on the International Space Station...
on July 14, 2001. Before Quest was attached, Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
n spacewalks using Orlan suits could only be done from the Zvezda service module and American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
spacewalks using EMUs were only possible when a Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
was docked. The arrival of Pirs docking compartment on September 16, 2001 provided another airlock from which Orlan spacewalks can be conducted.
Design
The Quest airlock consists of two segments, the "Equipment lock" that stores spacesuits and equipment, and the "Crew Lock" from which astronauts can exit into space. It was derived from the Space Shuttle airlock, although it was significantly modified to waste less atmospheric gas when used. It was attached to the starboard CBMCommon Berthing Mechanism
The common berthing mechanism is a berthing mechanism used to connect all non-Russian pressurized modules of the International Space Station....
of the Unity
Unity Module
thumb|right|300px|ISS Unity connecting module The Unity connecting module was the first U.S.-built component of the International Space Station....
during STS-104
STS-104
STS-104 was a Space Shuttle mission to the International Space Station flown by Space Shuttle Atlantis. Its primary objectives were to install the Quest Joint Airlock and help perform maintenance on the International Space Station...
. It has mountings for four high-pressure gas tanks, two containing oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
and two containing nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
, which provides for atmospheric replenishment to the American side of the space station, most specifically for the gas lost after a hatch opening during a space walk.
Quest was necessary because American suits will not fit through a Russian airlock hatch and have different components, fittings, and connections. The airlock is designed to contain equipment that can work with both types of spacesuits, however, it is currently only able to host American spacewalks because the equipment necessary to work with Russian space suits has not been launched yet, which required the Expedition 9
Expedition 9
Expedition 9 was the 9th expedition to the International Space Station.-Crew:-Mission parameters:*Perigee: 384 km*Apogee: 396 km*Inclination: 51.6°*Period: 92 minthumb|left|250px|Edward M...
crew to take a circuitous route to a worksite because of problems with the American space suits.
Camp out procedure
Quest provides an environment where astronauts can "camp out" before a spacewalk in a reduced-nitrogen atmosphere to purge nitrogen from their bloodstream and avoid decompression sicknessDecompression sickness
Decompression sickness describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization...
in the low pressure, 5 psi (34.5 kPa), pure-oxygen atmosphere of the spacesuit. The previous method of preparing for spacewalks involved breathing pure oxygen for several hours prior to an EVA to purge the body of nitrogen. In April 2006, Expedition 12
Expedition 12
Expedition 12 was the 12th expedition to the International Space Station, launched from Kazakhstan using the Russian Soyuz TMA-7 spacecraft...
Commander Bill McArthur
William S. McArthur
William Surles McArthur, Jr. is a retired U.S. Army Colonel, a NASA astronaut, and a veteran of three space shuttle missions and one expedition to the International Space Station via the Russian Soyuz capsule.-Army career:...
and Expedition 13
Expedition 13
Expedition 13 was the 13th expedition to the International Space Station , and launched at 02:30 UTC on 30 March 2006. The expedition used the Soyuz TMA-8 spacecraft, which stayed at the station for the duration of the expedition for emergency evacuation....
flight engineer Jeffrey Williams tested a new method of preparing for spacewalks by "camping out" or spending the night in the Quest airlock. In the chamber, the pressure was reduced from the normal 14.7 to 10.2 psi (101.4 to 70.3 kPa). Four hours into the Expedition 13 crew's sleep period, an error tone prompted mission controllers to cut short the activity, but the test was still deemed a success. American spacewalk activities thereafter have employed the "camp out" pre-breathing technique.
High-Pressure Gas Tanks
Two oxygen and two nitrogen High-Pressure Gas Tanks are attached externally to the airlock. These tanks provide a replenishable source of gas to the Atmosphere Control and Supply System and 900 psi (6.2 MPa) oxygen for recharging the space suits (EMUs). Recharging the high pressure tanks is accomplished by the orbiter when it is docked to the station's Pressurized Mating Adapter 2 or Pressurized Mating Adapter 3, using lines that are routed through the pressurized elements. The Oxygen Recharge Compressor Assembly (ORCA) is used to pump oxygen from the shuttle tanks into the high-pressure oxygen tanks on the space station.Construction
The airlock and tank systems were built out of aluminiumAluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
and tested at NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
's Marshall Space Flight Center
Marshall Space Flight Center
The George C. Marshall Space Flight Center is the U.S. government's civilian rocketry and spacecraft propulsion research center. The largest center of NASA, MSFC's first mission was developing the Saturn launch vehicles for the Apollo moon program...
in Huntsville, Alabama
Huntsville, Alabama
Huntsville is a city located primarily in Madison County in the central part of the far northern region of the U.S. state of Alabama. Huntsville is the county seat of Madison County. The city extends west into neighboring Limestone County. Huntsville's population was 180,105 as of the 2010 Census....
by the Boeing Company.
Airlock specifications
- Material: aluminium
- Length: 5.5 metres (18 ft)
- Diameter: 4 metres (13.1 ft)
- Weight: 6064 kilograms (13,368.8 lb)
- Volume: 34 cubic metres (1,200.7 cu ft)
- Cost: $164 million, including tanks