Wet workshop
Encyclopedia
Wet workshop is the idea of using a spent rocket
stage as a makeshift space station
. A liquid-fuel rocket
primarily consists of two large, airtight fuel tanks; it was realized that the fuel tanks could be retrofitted into the living quarters of a space station. A large rocket stage would reach a low Earth orbit
and undergo later modification. This would make for a cost-effective reuse of hardware that would otherwise have no further purpose, but the in-orbit modification of the rocket stage could prove difficult and expensive.
A wet workshop is contrasted with a "dry workshop", where the empty upper stage is internally outfitted on the ground before launch with a human habitat and other equipment. Then the upper stage is launched into orbit by a sufficiently powerful rocket.
Wernher von Braun
proposed a wet workshop concept for launch on the Saturn V
. His design modified the S-II
second stage of the Saturn V stack to allow it to be used as living space once reaching orbit. Since the S-IC
lower stage of the Saturn V cannot reach orbit on its own, the S-II would have to fire, and then vent out any remaining fuel once it reached orbit. To allow this, the floors of the station were made of an open grid which allowed the fuel to pass through easily to the piping at the bottom of the tanks. The structure also presented convenient hand and footholds.
Since the entire fuel load would be needed to reach orbit, additional life support equipment could not be stored inside the S-II during launch. von Braun's design placed all of this ancillary equipment in a large cylindrical carrier, which would be carried on top of the S-II stage in place of the S-IVB
normally placed there. After reaching orbit and venting, a large access hatch in the top of the S-II's hydrogen tank would be opened. The cylindrical cargo module would then be inserted hydraulically into the tank through this opening, sealed, and then the tank would be repressurized to form a large living space. Power would be provided by solar cells lining the outside of the S-II.
During the 1960s, as the Apollo mission transitioned from development to launch, a number of groups inside NASA were studying the post-Apollo era. Many ideas for continuing use of the existing Saturn hardware were proposed, and some of these were collected under the "Apollo X" banner. But by the time Apollo X was starting to look for funding, the Saturn V lines had been planned to shut down after producing just enough Saturn V's for the moon missions alone. However, during the same period of time, on-orbit testing of the Apollo systems was proceeding much better than expected, and a number of proposed shake-down missions were no longer required. This left a small number of Saturn IB
launchers available for use.
The Saturn IB stack consists of two main stages, the booster and a S-IVB stage on top, both of which needed to be fired in order to reach orbit. An S-IVB stage could be modified in a fashion similar to von Braun's original proposals, making a smaller but perfectly usable station. In this case the equipment would be carried on top of the S-IVB in the location normally reserved for the Lunar Module, but the lack of a large access port meant it would have to remain there instead of being inserted into the tank. Considerable design work along these lines was carried out.
Ironically, when the later Apollo missions were canceled (18 through 20), a supply of Saturn V's became available. By this time so much work had been done on the S-IV-derived system that they decided to continue along those lines instead. The Saturn V had enough power to place the station in orbit without firing the S-IVB, and the design was flown as the Skylab
"dry workshop", even though it retained many of its original wet workshop design features, notably the open mesh flooring.
Another project involving the Apollo-derived wet workshop was the proposed Manned Venus Flyby
.
's external tank
(ET) have also been studied. During launch the ET accelerates to about 98% of orbital speed before being dropped and deliberately spun in order to increase its drag. A number of people have proposed keeping the ET attached to the Shuttle all the way into orbit, bleeding off any remaining fuel through the Space Shuttle Main Engines's, which would be "left open". One such test had been scheduled, but was canceled after the Space Shuttle Challenger disaster
dramatically changed safety rules.
The ET would provide a huge working space, and one major problem with various wet workshop designs is what to do with all of it. The oxygen tank, the smaller of the two tanks inside the ET, is itself much larger than the entire Space Station Freedom
even in its fully expanded form. Additionally, getting access to the interior is possible though "manholes" used for inspection during construction, but it is not clear if realistic amounts of building materials could be inserted into the tank after reaching orbit. Nevertheless the problem has been studied repeatedly.
A similar concept, the "Aft Cargo Carrier", was studied by Martin Marietta
in 1984. This consisted of a large cylindrical cargo container bolted onto the bottom of the ET, which offered the same volume as the Space Shuttle orbiter's cargo bay, but would be able to carry wider, bulkier loads. The same basic layout was also used as the basis for a short-duration station design. Although not a wet workshop in the conventional sense, the station piggybacks on the fuel tank and is therefore related to some degree.
Rocket
A rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...
stage as a makeshift space station
Space station
A space station is a spacecraft capable of supporting a crew which is designed to remain in space for an extended period of time, and to which other spacecraft can dock. A space station is distinguished from other spacecraft used for human spaceflight by its lack of major propulsion or landing...
. A liquid-fuel rocket
Liquid rocket
A liquid-propellant rocket or a liquid rocket is a rocket engine that uses propellants in liquid form. Liquids are desirable because their reasonably high density allows the volume of the propellant tanks to be relatively low, and it is possible to use lightweight pumps to pump the propellant from...
primarily consists of two large, airtight fuel tanks; it was realized that the fuel tanks could be retrofitted into the living quarters of a space station. A large rocket stage would reach a low Earth orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
and undergo later modification. This would make for a cost-effective reuse of hardware that would otherwise have no further purpose, but the in-orbit modification of the rocket stage could prove difficult and expensive.
A wet workshop is contrasted with a "dry workshop", where the empty upper stage is internally outfitted on the ground before launch with a human habitat and other equipment. Then the upper stage is launched into orbit by a sufficiently powerful rocket.
Apollo-derived
Wernher von Braun
Wernher Magnus Maximilian, Freiherr von Braun was a German rocket scientist, aerospace engineer, space architect, and one of the leading figures in the development of rocket technology in Nazi Germany during World War II and in the United States after that.A former member of the Nazi party,...
proposed a wet workshop concept for launch on the Saturn V
Saturn V
The Saturn V was an American human-rated expendable rocket used by NASA's Apollo and Skylab programs from 1967 until 1973. A multistage liquid-fueled launch vehicle, NASA launched 13 Saturn Vs from the Kennedy Space Center, Florida with no loss of crew or payload...
. His design modified the S-II
S-II
The S-II was the second stage of the Saturn V rocket. It was built by North American Aviation. Using liquid hydrogen and liquid oxygen it had five J-2 engines in a cross pattern...
second stage of the Saturn V stack to allow it to be used as living space once reaching orbit. Since the S-IC
S-IC
The S-IC was the first stage of the Saturn V rocket. The S-IC first stage was built by The Boeing Company. Like the first stages of most rockets, most of its mass of over two thousand metric tonnes at launch was propellant, in this case RP-1 rocket fuel and liquid oxygen oxidizer...
lower stage of the Saturn V cannot reach orbit on its own, the S-II would have to fire, and then vent out any remaining fuel once it reached orbit. To allow this, the floors of the station were made of an open grid which allowed the fuel to pass through easily to the piping at the bottom of the tanks. The structure also presented convenient hand and footholds.
Since the entire fuel load would be needed to reach orbit, additional life support equipment could not be stored inside the S-II during launch. von Braun's design placed all of this ancillary equipment in a large cylindrical carrier, which would be carried on top of the S-II stage in place of the S-IVB
S-IVB
The S-IVB was built by the Douglas Aircraft Company and served as the third stage on the Saturn V and second stage on the Saturn IB. It had one J-2 engine...
normally placed there. After reaching orbit and venting, a large access hatch in the top of the S-II's hydrogen tank would be opened. The cylindrical cargo module would then be inserted hydraulically into the tank through this opening, sealed, and then the tank would be repressurized to form a large living space. Power would be provided by solar cells lining the outside of the S-II.
During the 1960s, as the Apollo mission transitioned from development to launch, a number of groups inside NASA were studying the post-Apollo era. Many ideas for continuing use of the existing Saturn hardware were proposed, and some of these were collected under the "Apollo X" banner. But by the time Apollo X was starting to look for funding, the Saturn V lines had been planned to shut down after producing just enough Saturn V's for the moon missions alone. However, during the same period of time, on-orbit testing of the Apollo systems was proceeding much better than expected, and a number of proposed shake-down missions were no longer required. This left a small number of Saturn IB
Saturn IB
The Saturn IB was an American launch vehicle commissioned by the National Aeronautics and Space Administration for use in the Apollo program...
launchers available for use.
The Saturn IB stack consists of two main stages, the booster and a S-IVB stage on top, both of which needed to be fired in order to reach orbit. An S-IVB stage could be modified in a fashion similar to von Braun's original proposals, making a smaller but perfectly usable station. In this case the equipment would be carried on top of the S-IVB in the location normally reserved for the Lunar Module, but the lack of a large access port meant it would have to remain there instead of being inserted into the tank. Considerable design work along these lines was carried out.
Ironically, when the later Apollo missions were canceled (18 through 20), a supply of Saturn V's became available. By this time so much work had been done on the S-IV-derived system that they decided to continue along those lines instead. The Saturn V had enough power to place the station in orbit without firing the S-IVB, and the design was flown as the Skylab
Skylab
Skylab was a space station launched and operated by NASA, the space agency of the United States. Skylab orbited the Earth from 1973 to 1979, and included a workshop, a solar observatory, and other systems. It was launched unmanned by a modified Saturn V rocket, with a mass of...
"dry workshop", even though it retained many of its original wet workshop design features, notably the open mesh flooring.
Another project involving the Apollo-derived wet workshop was the proposed Manned Venus Flyby
Manned Venus Flyby
A manned Venus flyby was considered by NASA in the mid 1960s as part of the Apollo Applications Program, using hardware derived from the Apollo program...
.
Shuttle-derived
Several similar conversions of the Space ShuttleSpace 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...
's external tank
Space Shuttle external tank
A Space Shuttle External Tank is the component of the Space Shuttle launch vehicle that contains the liquid hydrogen fuel and liquid oxygen oxidizer. During lift-off and ascent it supplies the fuel and oxidizer under pressure to the three Space Shuttle Main Engines in the orbiter...
(ET) have also been studied. During launch the ET accelerates to about 98% of orbital speed before being dropped and deliberately spun in order to increase its drag. A number of people have proposed keeping the ET attached to the Shuttle all the way into orbit, bleeding off any remaining fuel through the Space Shuttle Main Engines's, which would be "left open". One such test had been scheduled, but was canceled after the Space Shuttle Challenger disaster
Space Shuttle Challenger disaster
The Space Shuttle Challenger disaster occurred on January 28, 1986, when Space Shuttle Challenger broke apart 73 seconds into its flight, leading to the deaths of its seven crew members. The spacecraft disintegrated over the Atlantic Ocean, off the coast of central Florida at 11:38 am EST...
dramatically changed safety rules.
The ET would provide a huge working space, and one major problem with various wet workshop designs is what to do with all of it. The oxygen tank, the smaller of the two tanks inside the ET, is itself much larger than the entire Space Station Freedom
Space Station Freedom
Space Station Freedom was a NASA project to construct a permanently manned Earth-orbiting space station in the 1980s. Although approved by then-president Ronald Reagan and announced in the 1984 State of the Union Address, Freedom was never constructed or completed as originally designed, and after...
even in its fully expanded form. Additionally, getting access to the interior is possible though "manholes" used for inspection during construction, but it is not clear if realistic amounts of building materials could be inserted into the tank after reaching orbit. Nevertheless the problem has been studied repeatedly.
A similar concept, the "Aft Cargo Carrier", was studied by Martin Marietta
Martin Marietta
Martin Marietta Corporation was an American company founded in 1961 through the merger of The Martin Company and American-Marietta Corporation. The combined company became a leader in chemicals, aerospace, and electronics. In 1995, it merged with Lockheed Corporation to form Lockheed Martin. The...
in 1984. This consisted of a large cylindrical cargo container bolted onto the bottom of the ET, which offered the same volume as the Space Shuttle orbiter's cargo bay, but would be able to carry wider, bulkier loads. The same basic layout was also used as the basis for a short-duration station design. Although not a wet workshop in the conventional sense, the station piggybacks on the fuel tank and is therefore related to some degree.