Transposition, docking, and extraction

Last updated

Apollo11-03.png
The Apollo command and service module (CSM) turns around in preparation for docking with the lunar module (LM)
Apollo11-04.png
After docking, the CSM pulls the LM away from the launch vehicle's upper stage

Transposition, docking, and extraction (often abbreviated to transposition and docking) was a maneuver performed during Apollo lunar landing missions from 1969 to 1972, to withdraw the Apollo Lunar Module (LM) from its adapter housing which secured it to the Saturn V launch vehicle upper stage and protected it from the aerodynamic stresses of launch. The maneuver involved the command module pilot separating the Apollo Command and Service Module (CSM) from the adapter, turning the CSM around, and docking its nose to the Lunar Module, then pulling the combined spacecraft away from the upper stage. It was performed shortly after the trans-lunar injection maneuver that placed the Apollo spacecraft on a three-day trajectory to the Moon. The docking created a continuous, pressurized tunnel which permitted the astronauts to transfer internally between the CSM and the LM.

Contents

The same maneuver was performed on the 1975 Apollo–Soyuz Test Project (ASTP) mission to extract a special docking module used to connect the Apollo Command Module with the Soyuz spacecraft.

Procedure

Alfred Worden docks the Apollo 15 Command Module Endeavour to the Lunar Module Falcon

Transposition and docking was performed by the Command Module Pilot (CMP) (although, as a backup, the Commander and Lunar Module Pilot (or ASTP Docking Module Pilot) were also trained to perform the maneuver), and involved the following steps:

  1. A "CSM/LV Sep" button on the control panel was pressed, which ignited detonating cord and separated the CSM from the Spacecraft–lunar module adapter (SLA), and the four adapter panels from each other and the S-IVB upper stage. This exposed the LM.
  2. The CSM's translation thrusters were used to move it a safe distance away. Rotation thrusters were then used to pitch up the CSM 180° and roll it to the proper alignment angle for docking. Translation thrusters were then used to move it back to the LM. A T-shaped docking target on the top of the LM aligned optically with a reticle pattern on the CMP's left-hand docking window to ensure proper spacecraft alignment.
  3. A soft dock was achieved when a probe at the top of the CSM was inserted into a hole in the center of a cone-shaped drogue at the top of the LM and three small capture latches closed. Hard dock was achieved by activating a mechanism which retracted the probe and caused twelve more capture latches to close around the command module's docking flange.
  4. A pressure equalization valve in the CM forward hatch was opened to allow oxygen to fill the LM through a similar valve in its hatch that was left open at launch. When the pressure equalized, the pilot removed the CM hatch, removed the probe and drogue, inspected the capture latches, and connected two umbilical cables which electrically connected the CM and LM. He then replaced the CM hatch.
  5. The LM hold-down attachments and umbilical connection to the S-IVB Instrument Unit were released, and the CSM's translation thrusters were used to pull the CSM/LM stack a safe distance away from the S-IVB, which would then be steered by ground control either to a heliocentric orbit, or to a deliberate crash landing on the Moon.

The astronauts were in no hurry to complete this maneuver, which nominally took about an hour. [1] It would take longer if problems were encountered; for instance, Stuart Roosa had trouble getting the capture latches to engage for docking on Apollo 14, and the procedure took two hours and eighteen minutes. [2]

Missions

Apollo 7 S-IVB, with docking target inside the SLA. Note the right-hand panel is not fully opened to the same angle as the others, preventing a safe simulated docking approach. Apollo 7 Rondevouz.jpg
Apollo 7 S-IVB, with docking target inside the SLA. Note the right-hand panel is not fully opened to the same angle as the others, preventing a safe simulated docking approach.

Transposition and docking was performed on all Apollo missions which carried both the CSM and the LM, from Apollo 9 onward. Transposition and a mock LM-docking approach was first simulated on the Earth-orbiting Apollo 7 flight (which carried a docking target in the SLA, but no LM). The "Block I" SLA used on the early Saturn IB launch vehicles had panels that opened at a 45° angle but did not separate from the S‑IVB. One of the panels did not open the full angle, preventing the crew from approaching the S‑IVB for fear they might strike this panel. This was corrected with the "Block II" SLA design used on all crewed Saturn V Apollo flights (starting with Apollo 8), which detached the panels and pushed them away from the S‑IVB with springs.

The last mission to use the maneuver was the Apollo–Soyuz Test Project mission, in which the Apollo CSM docked to a specially designed adapter module which carried docking equipment compatible with the Soyuz 19 spacecraft.

See also

Related Research Articles

Apollo program 1961–1972 program which landed the first humans on the Moon

The Apollo program, also known as Project Apollo, was the third United States human spaceflight program carried out by the National Aeronautics and Space Administration (NASA), which succeeded in preparing and landing the first humans on the Moon from 1968 to 1972. It was first conceived during Dwight D. Eisenhower's administration as a three-person spacecraft to follow the one-person Project Mercury, which put the first Americans in space. Apollo was later dedicated to President John F. Kennedy's national goal for the 1960s of "landing a man on the Moon and returning him safely to the Earth" in an address to Congress on May 25, 1961. It was the third US human spaceflight program to fly, preceded by the two-person Project Gemini conceived in 1961 to extend spaceflight capability in support of Apollo.

Apollo 7 First crewed flight of the Apollo space program

Apollo 7 was the first crewed flight in NASA's Apollo program, and saw the resumption of human spaceflight by the agency after the fire that killed the three Apollo 1 astronauts during a launch rehearsal test on January 27, 1967. The Apollo 7 crew was commanded by Walter M. Schirra, with command module pilot Donn F. Eisele and lunar module pilot R. Walter Cunningham.

Apollo 9 3rd crewed mission of the Apollo space program

Apollo 9 was the third human spaceflight in NASA's Apollo program. Flown in low Earth orbit, it was the second crewed Apollo mission that the United States launched via a Saturn V rocket, and was the first flight of the full Apollo spacecraft: the command and service module (CSM) with the Lunar Module (LM). The mission was flown to qualify the LM for lunar orbit operations in preparation for the first Moon landing by demonstrating its descent and ascent propulsion systems, showing that its crew could fly it independently, then rendezvous and dock with the CSM again, as would be required for the first crewed lunar landing. Other objectives of the flight included firing the LM descent engine to propel the spacecraft stack as a backup mode, and use of the portable life support system backpack outside the LM cabin.

Apollo 12 Second crewed mission to land on the Moon.

Apollo 12 was the sixth crewed flight in the United States Apollo program and the second to land on the Moon. It was launched on November 14, 1969, from the Kennedy Space Center, Florida. Commander Charles "Pete" Conrad and Lunar Module Pilot Alan L. Bean performed just over one day and seven hours of lunar surface activity while Command Module Pilot Richard F. Gordon remained in lunar orbit.

Apollo Lunar Module Lander used in the Apollo program

The Apollo Lunar Module, or simply Lunar Module, originally designated the Lunar Excursion Module (LEM), was the Lunar lander spacecraft that thrusted and travelled with momentum between outer Exosphere and the Moon's surface during the United States' Apollo program. It was the first crewed spacecraft to operate exclusively in the airless vacuum of space, and remains the only crewed vehicle to land anywhere beyond Earth. The Lunar Phase were Waxing Crescent, the Launch were vertical and the Rocket flown against the rotation of Earth, the reason is the Gravitational Force of Earth, the Landing on the Moon will be Tangential and the Spacecraft will thrust and have either a Constant Momentum or an Increasing Momentum, Increasing for a reason the Lunar Lander can hardly turn 180 degrees to decrease Momentum, by applying thrusters again at the same direction, Momentum will increase, from Tangent Exosphere to near Tangent Moon Orbit. The calculated location is the lighted side of the Moon, the Waxing Crescent as seen on Earth.

Apollo–Soyuz First joint U.S.–Soviet space flight

Apollo–Soyuz was the first manned international space mission, carried out jointly by the United States and the Soviet Union in July 1975. Millions of people around the world watched on television as a United States Apollo module docked with a Soviet Union Soyuz capsule. The project, and its memorable handshake in space, was a symbol of détente between the two superpowers during the Cold War, and it is generally considered to mark the end of the Space Race, which had begun in 1957 with the Soviet Union's launch of Sputnik 1.

AS-201 1966 uncrewed, suborbital test flight within the Apollo program

AS-201, flown February 26, 1966, was the first uncrewed test flight of an entire production Block I Apollo command and service module and the Saturn IB launch vehicle. The spacecraft consisted of the second Block I command module and the first Block I service module. The suborbital flight was a partially successful demonstration of the service propulsion system and the reaction control systems of both modules, and successfully demonstrated the capability of the command module's heat shield to survive re-entry from low Earth orbit.

Apollo (spacecraft)

The Apollo spacecraft was composed of three parts designed to accomplish the American Apollo program's goal of landing astronauts on the Moon by the end of the 1960s and returning them safely to Earth. The expendable (single-use) spacecraft consisted of a combined command and service module (CSM) and an Apollo Lunar Module (LM). Two additional components complemented the spacecraft stack for space vehicle assembly: a spacecraft–LM adapter (SLA) designed to shield the LM from the aerodynamic stress of launch and to connect the CSM to the Saturn launch vehicle and a launch escape system (LES) to carry the crew in the command module safely away from the launch vehicle in the event of a launch emergency.

Saturn IB American rocket used in the Apollo program during the 1960s and 70s

The Saturn IB was an American launch vehicle commissioned by the National Aeronautics and Space Administration (NASA) for the Apollo program. It uprated the Saturn I by replacing the S-IV second stage, with the S-IVB. The S-IB first stage also increased the S-I baseline's thrust from 1,500,000 pounds-force (6,700,000 N) to 1,600,000 pounds-force (7,100,000 N) and propellant load by 3.1%. This increased the Saturn I's low Earth orbit payload capability from 20,000 pounds (9,100 kg) to 46,000 pounds (21,000 kg), enough for early flight tests of a half-fueled Apollo command and service module (CSM) or a fully fueled Apollo Lunar Module (LM), before the larger Saturn V needed for lunar flight was ready.

Skylab Rescue Backup rescue flight as part of a contingency plan for the Skylab space station

The Skylab Rescue Mission was a backup rescue flight as part of a contingency plan for the Skylab space station. It used a modified Apollo Command Module that could be launched with a crew of two and return a crew of five.

Apollo command and service module Component of the Apollo spacecraft

The Apollo command and service module (CSM) was one of two principal components of the United States Apollo spacecraft, used for the Apollo program, which landed astronauts on the Moon between 1969 and 1972. The CSM functioned as a mother ship, which carried a crew of three astronauts and the second Apollo spacecraft, the Apollo Lunar Module, to lunar orbit, and brought the astronauts back to Earth. It consisted of two parts: the conical command module, a cabin that housed the crew and carried equipment needed for atmospheric reentry and splashdown; and the cylindrical service module which provided propulsion, electrical power and storage for various consumables required during a mission. An umbilical connection transferred power and consumables between the two modules. Just before reentry of the command module on the return home, the umbilical connection was severed and the service module was cast off and allowed to burn up in the atmosphere.

Space rendezvous Series of orbital maneuvers to bring two spacecraft into the vicinity of each other

A space rendezvous is a set of orbital maneuvers during which two spacecraft, one of which is often a space station, arrive at the same orbit and approach to a very close distance. Rendezvous requires a precise match of the orbital velocities and position vectors of the two spacecraft, allowing them to remain at a constant distance through orbital station-keeping. Rendezvous may or may not be followed by docking or berthing, procedures which bring the spacecraft into physical contact and create a link between them.

Apollo abort modes were procedures by which the nominal launch of an Apollo spacecraft, either the Saturn IB or Saturn V rocket, could be terminated. The abort of the flight allowed for the rescue of the crew if the rocket failed catastrophically. Depending on how far the flight had progressed, differned procedure or modes would be used. In the history of the Apollo Program, none of the abort modes were ever used on any of the fifteen crewed Apollo spacecraft flights.

The Apollo Applications Program (AAP) was created as early as 1966 by NASA headquarters to develop science-based human spaceflight missions using hardware developed for the Apollo program. AAP was the ultimate development of a number of official and unofficial Apollo follow-on projects studied at various NASA labs. However, the AAP's ambitious initial plans became an early casualty when the Johnson Administration declined to support it adequately, partly in order to implement its Great Society set of domestic programs while remaining within a $100 billion budget. Thus, Fiscal Year 1967 ultimately allocated $80 million to the AAP, compared to NASA's preliminary estimates of $450 million necessary to fund a full-scale AAP program for that year, with over $1 billion being required for FY 1968. The AAP eventually led to Skylab, which absorbed much of what had been developed under Apollo Applications.

Journey of Apollo 15 to the Moon Overview from launch to lunar orbit insertion of Apollo 15.

Launched at 9:34:00 am EST on July 26, 1971, Apollo 15 took four days to reach the Moon. After spending two hours in orbit around the Earth, the S-IVB third stage of the Saturn V was reignited to send them to the Moon.

Several planned missions of the Apollo crewed Moon landing program of the 1960s and 1970s were canceled for a variety of reasons, including changes in technical direction, the Apollo 1 fire, hardware delays, and budget limitations. After the landing by Apollo 12, Apollo 20, which would have been the final crewed mission to the Moon, was canceled to allow Skylab to launch as a "dry workshop". The next two missions, Apollos 18 and 19, were later canceled after the Apollo 13 incident and further budget cuts. Two Skylab missions also ended up being canceled. Two complete Saturn Vs ended up going unused and are currently on display in the United States.

Manned Venus flyby

Manned Venus Flyby was a 1967–1968 NASA proposal to send three astronauts on a flyby mission to Venus in an Apollo-derived spacecraft in 1973–1974, using a gravity assist to shorten the return journey to Earth.

Skylab B Proposed second US space station similar to Skylab

Skylab B was a proposed second US space station similar to Skylab that was planned to be launched by NASA for different purposes, mostly involving the Apollo–Soyuz Test Project, but was canceled due to lack of funding. Two Skylab modules were built in 1970 by McDonnell Douglas for the Skylab program, originally the Apollo Applications Program. The first was launched in 1973 and the other put in storage, while NASA considered how to use the remaining assets from Apollo.

Docking and berthing of spacecraft Joining of two or more space vehicles

Docking and berthing of spacecraft is the joining of two space vehicles. This connection can be temporary, or partially permanent such as for space station modules.

Apollo Docking Mechanism

The docking mechanism of the Apollo was a "probe and drogue" system designed to allow the Apollo Command/Service Module (CSM) to dock with the Apollo Lunar Module. The same system was later used for the Skylab 2, Skylab 3 and Skylab 4 CSMs to dock with the Skylab space station, and the Apollo–Soyuz Test Project CSM to dock with a Docking Module adapter which allowed docking with the Soyuz 19 spacecraft. There were 12 hard latches.

References

  1. Orloff, Richard W. (September 2004). Apollo 11 Timeline. Washington, D.C.: NASA History Division. Retrieved June 9, 2016.
  2. Orloff, Richard W. (September 2004). Apollo 14 Summary. Washington, D.C.: NASA History Division. Retrieved June 9, 2016.