Space rendezvous
Encyclopedia
A space rendezvous is an orbital maneuver
during which two spacecraft
, one of which is often a space station
, arrive at the same orbit
and approach to a very close distance (e.g. within visual contact). Rendezvous requires a precise match of the orbital velocities
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.
and Vostok 5 and 6
. In both cases, the launch rockets' guidance systems inserted the two craft into nearly identical orbits; however the precision of such a system was not nearly enough to achieve true rendezvous. This required at least one spacecraft to have its own thrusters with which it could adjust its orbit to precisely match that of the other craft, and the Vostok capsule lacked such thrusters. The initial separation distances were in the range of 5 kilometres (3.1 mi) to 6.5 kilometres (4 mi), but slowly diverged to thousands of kilometres (over a thousand miles) over the course of the missions.
The first space rendezvous was attempted on June 3, 1965 by US astronaut Jim McDivitt on Gemini 4
with the spent Titan II
launch vehicle's upper stage. McDivitt was unable to get close enough to the stage to achieve station-keeping, because of depth-perception problems and propellant venting which kept moving the stage around.
on December 15, 1965, who maneuvered the Gemini 6A
spacecraft within 1 feet (30.5 cm) of its sister craft Gemini 7
. The spacecraft were not equipped to dock with each other, but maintained station-keeping for more than 20 minutes. Schirra later commented:
, under the command of Neil Armstrong
, rendezvoused and docked with an unmanned Agena Target Vehicle
. This had been originally planned for Gemini 6, but had to be cancelled when the Agena vehicle was destroyed during liftoff. The docking mission was then replaced with the Gemini 7/6A rendezvous mission.
The Soviets carried out the first automated, unmanned docking between Cosmos 186 and Cosmos 188 on October 30, 1967.
The first Soviet cosmonaut to attempt a manual docking was Georgi Beregovoi
who unsuccessfully tried to dock his Soyuz 3
craft with the unmanned Soyuz 2
in October 1968. He was able to bring his craft from 200 metres (656.2 ft) to as close as 1 foot (0.3048 m), but was unable to dock before exhausting his maneuvering fuel.
The Soviet's first successful manned docking occurred on January 16, 1969 when Soyuz 4
and Soyuz 5
docked and exchanged two crew members.
The first rendezvous of two spacecraft from different countries took place on June 17, 1975, when an Apollo spacecraft docked with a Soyuz spacecraft as part of the Apollo-Soyuz Test Project
.
The first multiple space docking took place when both Soyuz 26
and Soyuz 27
were docked to the Salyut 6
space station during January 1978.
s. The first of these was the rendezvous and docking on June 7, 1971 of the ill-fated Soyuz 11
mission with the Salyut 1
station. In the past, human spaceflight
missions have made rendezvous with each of six Salyut
stations, with Skylab
, with Mir
and with the International Space Station
(ISS). Currently Soyuz spacecraft
are used to bring crew to the ISS.
Robotic spacecraft
are also used to rendezvous with and resupply space stations. Soyuz
and Progress spacecraft
have automatically docked with both Mir and the ISS using the Kurs docking system
, while the Automated Transfer Vehicle
has docked with ISS using a laser system. The robotic H-II Transfer Vehicle
, however, is planned to fly to a close rendezvous without docking, in order to allow the ISS's Canadarm2 to bring it into dock.
Space rendezvous have been used for a variety of other purposes, including recent service missions to the Hubble Space Telescope
. Historically, for the missions of Project Apollo
that landed astronauts on the Moon
, the ascent stage of the Apollo Lunar Module
would rendezvous and dock with the Apollo Command/Service Module
in lunar orbit rendezvous
maneuvers. Also, the STS-49
crew rendezvoused with and attached a rocket motor to the Intelsat
VI
F-3 communications satellite
to allow it to make an orbital maneuver
.
Possible future rendezvous may be made by a yet to be developed automated Hubble Robotic Vehicle (HRV), and by the CX-OLEV, which is being developed for rendezvous with a geosynchronous satellite
that has run out of fuel. The CX-OLEV would take over orbital stationkeeping
and/or finally bring the satellite to a graveyard orbit, after which the CX-OLEV can possibly be reused for another satellite. Gradual transfer from the geostationary transfer orbit
to the geosynchronous orbit
will take a number of months, using Hall effect thruster
s. http://www.orbitalrecovery.com/news15.html
Alternatively the two spacecraft are already together, and just undock and dock in a different way:
Anti-satellite weapon
s partly fall under the category of hostile rendezvous. Kinetic projectiles do not use explosives or radiation, but just collide
.
For this to be possible, both spacecraft must be in the same orbital plane
, and the phase of the orbit
must be matched. This can be achieved by one spacecraft being in a higher orbit than the other, and the lower orbit will gain on the higher orbit over time.
The active vehicle is then put on an intercept course with the target. The closure rate is then reduced by use of the active vehicle's reaction control system
.
Docking typically occurs at a rate of 0.1 ft/s (0.03048 m/s) to 0.2 ft/s (0.06096 m/s).
A variety of spacecraft control techniques may be used to effect the translational
and rotational
maneuvers
necessary for proximity operations and docking.
V-bar approach
An approach of the active, or "chaser", spacecraft horizontally along the passive spacecraft velocity vector—that is, from behind and in the same direction as the orbital velocity of the passive spacecraft—is called called a V-bar approach.
STS-104
was the third Space Shuttle
mission to conduct a V-bar arrival at the International Space Station
. The V-bar, or velocity vector
, extends along a line directly ahead of the station. Shuttles approach the ISS along the V-bar when docking at the PMA-2
docking port.
R-bar approach
An approach of the active, or "chaser", spacecraft vertically along the passive spacecraft radial vector—that is, from below and orthogonal to the orbital velocity of the passive spacecraft—is called called an R-bar approach.
Astrotech proposed meeting ISS cargo needs with a vehicle which would approach the station, "using a traditional nadir R-bar approach."
Z-bar approach
An approach of the active, or "chaser", spacecraft horizontally from the side and orthogonal to the orbital plane
of the passive spacecraft—that is, from the side and out-of-plane of the orbit of the passive spacecraft—is called called a Z-bar approach.
H-bar approach
Orbital maneuver
In spaceflight, an orbital maneuver is the use of propulsion systems to change the orbit of a spacecraft.For spacecraft far from Earth—for example those in orbits around the Sun—an orbital maneuver is called a deep-space maneuver .-delta-v:...
during which two spacecraft
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
, one of which is often a 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...
, arrive at the same orbit
Orbit
In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...
and approach to a very close distance (e.g. within visual contact). Rendezvous requires a precise match of the orbital velocities
Orbital velocity
Orbital velocity can refer to the following:* The orbital speed of a body in a gravitational field.* The velocity of particles due to wave motion, in particular in wind waves....
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.
History
In 1962 and again 1963, the Soviet Union launched pairs of spacecraft simultaneously, Vostok 3 and 4Vostok 3
Vostok 3 was a spaceflight of the Soviet space program intended to determine the ability of the human body to function in conditions of weightlessness and test the endurance of the Vostok 3KA spacecraft over longer flights...
and Vostok 5 and 6
Vostok 5
-Backup crew:-Reserve crew:-Mission parameters:*Mass *Apogee: *Perigee: *Inclination: 64.9°*Period: 88.4 minutes...
. In both cases, the launch rockets' guidance systems inserted the two craft into nearly identical orbits; however the precision of such a system was not nearly enough to achieve true rendezvous. This required at least one spacecraft to have its own thrusters with which it could adjust its orbit to precisely match that of the other craft, and the Vostok capsule lacked such thrusters. The initial separation distances were in the range of 5 kilometres (3.1 mi) to 6.5 kilometres (4 mi), but slowly diverged to thousands of kilometres (over a thousand miles) over the course of the missions.
The first space rendezvous was attempted on June 3, 1965 by US astronaut Jim McDivitt on Gemini 4
Gemini 4
Gemini 4 was the second manned space flight in NASA's Project Gemini, occurring in June 1965. It was the tenth manned American spaceflight . Astronauts James McDivitt and Edward H. White, II circled the Earth 66 times in four days, making it the first US flight to approach the five-day flight of...
with the spent Titan II
Titan II
The Titan II was an intercontinental ballistic missile and space launcher developed by the Glenn L. Martin Company from the earlier Titan I missile. Titan II was originally used as an ICBM...
launch vehicle's upper stage. McDivitt was unable to get close enough to the stage to achieve station-keeping, because of depth-perception problems and propellant venting which kept moving the stage around.
First successful rendezvous
Rendezvous was first successfully accomplished by US astronaut Wally SchirraWally Schirra
Walter Marty Schirra, Jr. was an American test pilot, United States Navy officer, and one of the original Mercury 7 astronauts chosen for the Project Mercury, America's effort to put humans in space. He is the only person to fly in all of America's first three space programs...
on December 15, 1965, who maneuvered the Gemini 6A
Gemini 6A
-Backup crew:-Mission parameters:* Mass: * Perigee: * Apogee: * Inclination: 28.97°* Period: 88.7 min-Stationkeeping with GT-7:* Start: December 15, 1965 19:33 UTC* End: December 16, 1965 00:52 UTC-Objectives:...
spacecraft within 1 feet (30.5 cm) of its sister craft Gemini 7
Gemini 7
Gemini 7 was a 1965 manned spaceflight in NASA's Gemini program. It was the 4th manned Gemini flight, the 12th manned American flight and the 20th spaceflight of all time . The crew of Frank F. Borman, II and James A...
. The spacecraft were not equipped to dock with each other, but maintained station-keeping for more than 20 minutes. Schirra later commented:
First docking
The first docking of two spacecraft was achieved on March 16, 1966, when Gemini 8Gemini 8
-Backup crew:-Mission parameters:* Mass: * Perigee: * Apogee: * Inclination: 28.91°* Period: 88.83 min-Objectives:Gemini VIII had two major objectives, of which it achieved one...
, under the command of Neil Armstrong
Neil Armstrong
Neil Alden Armstrong is an American former astronaut, test pilot, aerospace engineer, university professor, United States Naval Aviator, and the first person to set foot upon the Moon....
, rendezvoused and docked with an unmanned Agena Target Vehicle
Agena Target Vehicle
The Agena Target Vehicle was an unmanned spacecraft used by NASA during its Gemini program to develop and practice orbital space rendezvous and docking techniques and to perform large orbital changes, in preparation for the Apollo program lunar missions.-Operations:Each ATV consisted of an Agena-D...
. This had been originally planned for Gemini 6, but had to be cancelled when the Agena vehicle was destroyed during liftoff. The docking mission was then replaced with the Gemini 7/6A rendezvous mission.
The Soviets carried out the first automated, unmanned docking between Cosmos 186 and Cosmos 188 on October 30, 1967.
The first Soviet cosmonaut to attempt a manual docking was Georgi Beregovoi
Georgi Beregovoi
Georgy Timofeyevich Beregovoy was a Soviet cosmonaut who commanded the space mission Soyuz 3 in 1968. At the time of his flight, Beregovoy was 47 years of age: he was the oldest human to go into space , three months and three days older than the second earliest-born astronaut, American John...
who unsuccessfully tried to dock his Soyuz 3
Soyuz 3
Soyuz 3 was a spaceflight mission launched by the Soviet Union on October 26, 1968. For four consecutive days, Commander Georgy Beregovoy piloted the Soyuz 7K-OK spacecraft through eighty-one orbits of Earth.-Crew:-Backup crew:...
craft with the unmanned Soyuz 2
Soyuz 2
Soyuz 2 was an unpiloted spacecraft in the Soyuz family intended to perform a docking maneuver with Soyuz 3. Although the two craft approached closely, the docking did not take place.-Other uses of name:...
in October 1968. He was able to bring his craft from 200 metres (656.2 ft) to as close as 1 foot (0.3048 m), but was unable to dock before exhausting his maneuvering fuel.
The Soviet's first successful manned docking occurred on January 16, 1969 when Soyuz 4
Soyuz 4
Soyuz 4 was launched on January 14, 1969. On board the Soyuz 7K-OK spacecraft was cosmonaut Vladimir Shatalov on his first flight. The aim of the mission was to dock with Soyuz 5, transfer two crew members from that spacecraft, and return to Earth...
and Soyuz 5
Soyuz 5
Soyuz 5 was a Soyuz mission using the Soyuz 7K-OK spacecraft launched by the Soviet Union on January 15, 1969, which docked with Soyuz 4 in orbit...
docked and exchanged two crew members.
The first rendezvous of two spacecraft from different countries took place on June 17, 1975, when an Apollo spacecraft docked with a Soyuz spacecraft as part of the Apollo-Soyuz Test Project
Apollo-Soyuz Test Project
-Backup crew:-Crew notes:Jack Swigert had originally been assigned as the command module pilot for the ASTP prime crew, but prior to the official announcement he was removed as punishment for his involvement in the Apollo 15 postage stamp scandal.-Soyuz crew:...
.
The first multiple space docking took place when both Soyuz 26
Soyuz 26
Soyuz 26 was Soviet manned mission, used to launch the crew of Salyut 6 EO-1, the first long duration crew on the space station Salyut 6.The Soyuz spacecraft was launched on December 10, 1977, and docked with the space station the next day...
and Soyuz 27
Soyuz 27
Soyuz 27 was a 1978 Soviet manned spacecraft which flew to the orbiting Salyut 6 space station, during the mission EP-1. It was the third manned flight to the station, and the second successful docking...
were docked to the Salyut 6
Salyut 6
Salyut 6 , DOS-5, was a Soviet orbital space station, the eighth flown as part of the Salyut programme. Launched on 29 September 1977 by a Proton rocket, the station was the first of the 'second-generation' type of space station. Salyut 6 possessed several revolutionary advances over the earlier...
space station during January 1978.
Uses
A frequent use of space rendezvous has been the transportation of crew and supplies to orbiting space stationSpace 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...
s. The first of these was the rendezvous and docking on June 7, 1971 of the ill-fated Soyuz 11
Soyuz 11
Soyuz 11 was the first manned mission to arrive at the world's first space station, Salyut 1. The mission arrived at the space station on June 7, 1971 and departed on June 30, 1971. The mission ended in disaster when the crew capsule depressurized during preparations for re-entry, killing the...
mission with the Salyut 1
Salyut 1
Salyut 1 was the first space station of any kind, launched by the USSR on April 19, 1971. It was launched unmanned using a Proton-K rocket. Its first crew came later in Soyuz 10, but was unable to dock completely; its second crew launched in Soyuz 11 and remained on board for 23 days...
station. In the past, human spaceflight
Human spaceflight
Human spaceflight is spaceflight with humans on the spacecraft. When a spacecraft is manned, it can be piloted directly, as opposed to machine or robotic space probes and remotely-controlled satellites....
missions have made rendezvous with each of six Salyut
Salyut
The Salyut program was the first space station program undertaken by the Soviet Union, which consisted of a series of nine space stations launched over a period of eleven years from 1971 to 1982...
stations, with 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...
, with Mir
Mir
Mir was a space station operated in low Earth orbit from 1986 to 2001, at first by the Soviet Union and then by Russia. Assembled in orbit from 1986 to 1996, Mir was the first modular space station and had a greater mass than that of any previous spacecraft, holding the record for the...
and with 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...
(ISS). Currently Soyuz spacecraft
Soyuz spacecraft
Soyuz , Union) is a series of spacecraft initially designed for the Soviet space programme by the Korolyov Design Bureau in the 1960s, and still in service today...
are used to bring crew to the ISS.
Robotic spacecraft
Robotic spacecraft
A robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to...
are also used to rendezvous with and resupply space stations. Soyuz
Soyuz spacecraft
Soyuz , Union) is a series of spacecraft initially designed for the Soviet space programme by the Korolyov Design Bureau in the 1960s, and still in service today...
and Progress spacecraft
Progress spacecraft
The Progress is a Russian expendable freighter spacecraft. The spacecraft is an unmanned resupply spacecraft during its flight but upon docking with a space station, it allows astronauts inside, hence it is classified manned by the manufacturer. It was derived from the Soyuz spacecraft, and is...
have automatically docked with both Mir and the ISS using the Kurs docking system
Kurs (docking system)
Kurs is a radio telemetry system used by the Soviet and later Russian space program.Kurs was developed by the Research Institute of Precision Instruments before 1985 and manufactured by the Kiev Radio Factory .- History :...
, while the Automated Transfer Vehicle
Automated Transfer Vehicle
The Automated Transfer Vehicle or ATV is an expendable, unmanned resupply spacecraft developed by the European Space Agency . ATVs are designed to supply the International Space Station with propellant, water, air, payload and experiments...
has docked with ISS using a laser system. The robotic H-II Transfer Vehicle
H-II Transfer Vehicle
The H-II Transfer Vehicle , called , is an unmanned resupply spacecraft used to resupply the Kibō Japanese Experiment Module and the International Space Station . The Japan Aerospace Exploration Agency has been working on the design since the early 1990s. The first mission, HTV-1, was originally...
, however, is planned to fly to a close rendezvous without docking, in order to allow the ISS's Canadarm2 to bring it into dock.
Space rendezvous have been used for a variety of other purposes, including recent service missions to the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
. Historically, for the missions of Project Apollo
Project Apollo
The Apollo program was the spaceflight effort carried out by the United States' National Aeronautics and Space Administration , that landed the first humans on Earth's Moon. Conceived during the Presidency of Dwight D. Eisenhower, Apollo began in earnest after President John F...
that landed astronauts on the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
, the ascent stage of the Apollo Lunar Module
Apollo Lunar Module
The Apollo Lunar Module was the lander portion of the Apollo spacecraft built for the US Apollo program by Grumman to carry a crew of two from lunar orbit to the surface and back...
would rendezvous and dock with the Apollo Command/Service Module
Apollo Command/Service Module
The Command/Service Module was one of two spacecraft, along with the Lunar Module, used for the United States Apollo program which landed astronauts on the Moon. It was built for NASA by North American Aviation...
in lunar orbit rendezvous
Lunar orbit rendezvous
Lunar orbit rendezvous is a key concept for human landing on the Moon and returning to Earth.In a LOR mission a main spacecraft and a smaller lunar module travel together into lunar orbit. The lunar module then independently descends to the lunar surface. After completion of the mission there, a...
maneuvers. Also, the STS-49
STS-49
-Mission parameters:*Mass:**Orbiter landing with payload: **Payload: *Perigee: *Apogee: *Inclination: 28.35°*Period: 90.6 min-Space walks:* Thuot and Hieb – EVA 1*EVA 1 Start: 10 May 1992 – 20:40 UTC...
crew rendezvoused with and attached a rocket motor to the Intelsat
Intelsat
Intelsat, Ltd. is a communications satellite services provider.Originally formed as International Telecommunications Satellite Organization , it was—from 1964 to 2001—an intergovernmental consortium owning and managing a constellation of communications satellites providing international broadcast...
VI
Intelsat VI
The Intelsat VI series of satellites were the 8th generation of geostationary communications satellites for the Intelsat Corporation. Designed and built by Hughes Aircraft Company in 1983-1991, there were five VI-series satellites built 601, 602, 603, 604, and 605.- Design :The Intelsat VI...
F-3 communications satellite
Communications satellite
A communications satellite is an artificial satellite stationed in space for the purpose of telecommunications...
to allow it to make an orbital maneuver
Orbital maneuver
In spaceflight, an orbital maneuver is the use of propulsion systems to change the orbit of a spacecraft.For spacecraft far from Earth—for example those in orbits around the Sun—an orbital maneuver is called a deep-space maneuver .-delta-v:...
.
Possible future rendezvous may be made by a yet to be developed automated Hubble Robotic Vehicle (HRV), and by the CX-OLEV, which is being developed for rendezvous with a geosynchronous satellite
Geosynchronous satellite
A geosynchronous Satellite is a satellite whose orbit on the Earth repeats regularly over points on the Earth over time. If such a satellite's orbit lies over the equator, the orbit is circular and its angular velocity is the same as the earth's, then it is called a geostationary satellite...
that has run out of fuel. The CX-OLEV would take over orbital stationkeeping
Orbital stationkeeping
In astrodynamics orbital station-keeping is a term used to describe the orbital maneuvers made by thruster burns that are needed to keep a spacecraft in a particular assigned orbit.For many Earth satellites the effects of the non-Keplerian forces, i.e...
and/or finally bring the satellite to a graveyard orbit, after which the CX-OLEV can possibly be reused for another satellite. Gradual transfer from the geostationary transfer orbit
Geostationary transfer orbit
A geosynchronous transfer orbit or geostationary transfer orbit is a Hohmann transfer orbit used to reach geosynchronous or geostationary orbit....
to the geosynchronous orbit
Geosynchronous orbit
A geosynchronous orbit is an orbit around the Earth with an orbital period that matches the Earth's sidereal rotation period...
will take a number of months, using Hall effect thruster
Hall effect thruster
In spacecraft propulsion, a Hall thruster is a type of ion thruster in which the propellant is accelerated by an electric field. Hall thrusters trap electrons in a magnetic field and then use the electrons to ionize propellant, efficiently accelerate the ions to produce thrust, and neutralize the...
s. http://www.orbitalrecovery.com/news15.html
Alternatively the two spacecraft are already together, and just undock and dock in a different way:
- Soyuz spacecraft from one docking point to another on the ISS or Salyut
- In the Apollo spacecraftApollo spacecraftThe Apollo spacecraft was composed of five combined 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...
, a maneuver known as transposition, docking, and extractionTransposition, docking, and extractionTransposition, docking, and extraction is a space rendezvous maneuver performed during the Apollo lunar missions of the 1960s and 70s...
was performed an hour or so after Trans Lunar InjectionTrans Lunar InjectionA Trans Lunar Injection is a propulsive maneuver used to set a spacecraft on a trajectory which will arrive at the Moon.Typical lunar transfer trajectories approximate Hohmann transfers, although low energy transfers have also been used in some cases, as with the Hiten probe...
of the sequence third stage of the Saturn VSaturn VThe 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...
rocket / LM inside LM adapter / CSM (in order from bottom to top at launch, also the order from back to front with respect to the current motion), with CSM manned, LM at this stage unmanned:- the CSM separated, while the four upper panels of the LM adapter were disposed of
- the CSM turned 180 degrees (from engine backward, toward LM, to forward)
- the CSM connected to the LM while that was still connected to the third stage
- the CSM/LM combination then separated from the third stage
Anti-satellite weapon
Anti-satellite weapon
Anti-satellite weapons are designed to incapacitate or destroy satellites for strategic military purposes. Currently, only the United States, the former Soviet Union, and the People's Republic of China are known to have developed these weapons. On September 13, 1985, the United States destroyed US...
s partly fall under the category of hostile rendezvous. Kinetic projectiles do not use explosives or radiation, but just collide
Collision
A collision is an isolated event which two or more moving bodies exert forces on each other for a relatively short time.Although the most common colloquial use of the word "collision" refers to accidents in which two or more objects collide, the scientific use of the word "collision" implies...
.
Phases and Methods
The standard technique for rendezvous and docking is to dock an active vehicle with a passive target. This technique has been used successfully for the Gemini, Apollo, Apollo/Soyuz, Salyut, Skylab, Mir, ISS, and TianGong programs.For this to be possible, both spacecraft must be in the same orbital plane
Orbital plane
Orbital plane may refer to:*Orbital plane *In anatomy, it refers to a specific area of the maxilla...
, and the phase of the orbit
Orbit phasing
In astrodynamics orbit phasing is the adjustment of the time-position of spacecraft along its orbit, usually described as adjusting the orbiting spacecraft's true anomaly....
must be matched. This can be achieved by one spacecraft being in a higher orbit than the other, and the lower orbit will gain on the higher orbit over time.
The active vehicle is then put on an intercept course with the target. The closure rate is then reduced by use of the active vehicle's reaction control system
Reaction control system
A reaction control system is a subsystem of a spacecraft whose purpose is attitude control and steering by the use of thrusters. An RCS system is capable of providing small amounts of thrust in any desired direction or combination of directions. An RCS is also capable of providing torque to allow...
.
Docking typically occurs at a rate of 0.1 ft/s (0.03048 m/s) to 0.2 ft/s (0.06096 m/s).
Rendezvous phases
Space rendezvous of an active, or "chaser", spacecraft with an (assumed) passive spacecraft may be divided into several phases, and typically starts with the two spacecraft in separate orbits, typically separated by more than 10000 kilometres (6,213.7 mi):| Phase | Separation distance | Typical phase duration |
|---|---|---|
| Drift Orbit A(out of sight, out of contact) | >2 λmax | 1 to 20 days |
| Drift Orbit B(in sight, in contact) | 2 λmax to 1 kilometres (3,280.8 ft) | 1 to 5 days |
| Proximity Operations A | 1000–100 m (3,280.8–328.1 ft) | 1 to 5 orbits |
| Proximity Operations B | 100–10 m (328.1–32.8 ft) | 45 – 90 minutes |
| Docking | <10 metres (32.8 ft) | <5 minutes |
A variety of spacecraft control techniques may be used to effect the translational
Translation (physics)
In physics, translation is movement that changes the position of an object, as opposed to rotation. For example, according to Whittaker:...
and rotational
Rotation
A rotation is a circular movement of an object around a center of rotation. A three-dimensional object rotates always around an imaginary line called a rotation axis. If the axis is within the body, and passes through its center of mass the body is said to rotate upon itself, or spin. A rotation...
maneuvers
Orbital maneuver
In spaceflight, an orbital maneuver is the use of propulsion systems to change the orbit of a spacecraft.For spacecraft far from Earth—for example those in orbits around the Sun—an orbital maneuver is called a deep-space maneuver .-delta-v:...
necessary for proximity operations and docking.
Methods of approach
The two most common methods of approach for proximity operations are V-bar and R-bar.V-bar approach
An approach of the active, or "chaser", spacecraft horizontally along the passive spacecraft velocity vector—that is, from behind and in the same direction as the orbital velocity of the passive spacecraft—is called called a V-bar approach.
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...
was the third 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...
mission to conduct a V-bar arrival at 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...
. The V-bar, or velocity vector
Orbital state vectors
In astrodynamics or celestial dynamics orbital state vectors are vectors of position and velocity that together with their time uniquely determine the state of an orbiting body....
, extends along a line directly ahead of the station. Shuttles approach the ISS along the V-bar when docking at the PMA-2
Pressurized Mating Adapter
The International Space Station uses three Pressurized Mating Adapters to interconnect spacecraft and modules with different docking mechanisms. The first two PMAs were launched with the Unity module in 1998 aboard STS-88...
docking port.
R-bar approach
An approach of the active, or "chaser", spacecraft vertically along the passive spacecraft radial vector—that is, from below and orthogonal to the orbital velocity of the passive spacecraft—is called called an R-bar approach.
Astrotech proposed meeting ISS cargo needs with a vehicle which would approach the station, "using a traditional nadir R-bar approach."
Z-bar approach
An approach of the active, or "chaser", spacecraft horizontally from the side and orthogonal to the orbital plane
Orbital elements
Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are generally considered in classical two-body systems, where a Kepler orbit is used...
of the passive spacecraft—that is, from the side and out-of-plane of the orbit of the passive spacecraft—is called called a Z-bar approach.
H-bar approach
See also
- Androgynous Peripheral Attach SystemAndrogynous Peripheral Attach SystemThe Androgynous Peripheral Attach System, or Androgynous Peripheral Assembly System, is a spacecraft docking mechanism used on the International Space Station. It is used to dock the Space Shuttle orbiter and to connect the Functional Cargo Block to Pressurized Mating Adapter-1...
- Common Berthing MechanismCommon Berthing MechanismThe common berthing mechanism is a berthing mechanism used to connect all non-Russian pressurized modules of the International Space Station....
- Lunar orbit rendezvousLunar orbit rendezvousLunar orbit rendezvous is a key concept for human landing on the Moon and returning to Earth.In a LOR mission a main spacecraft and a smaller lunar module travel together into lunar orbit. The lunar module then independently descends to the lunar surface. After completion of the mission there, a...
- Wally SchirraWally SchirraWalter Marty Schirra, Jr. was an American test pilot, United States Navy officer, and one of the original Mercury 7 astronauts chosen for the Project Mercury, America's effort to put humans in space. He is the only person to fly in all of America's first three space programs...
- Nodal regressionNodal regressionNodal precession is the precession of an orbital plane around the rotation axis of an astronomical body such as the Earth. This precession is due to the non spherical nature of a spinning body which creates a non spherical gravitational field....
causes precession of orbits around the Earth's axis
External links
- The Visitors (rendezvous)
- Space Rendezvous Video of Space Shuttle Atlantis and Space Station
- Satellite Interactive Java applet that lets you attempt an orbital rendezvous
- Handbook Automated Rendezvous and Docking of Spacecraft by Wigbert FehseWigbert FehseWigbert Fehse is a German engineer and researcher in the area of automatic space navigation, guidance, control and docking/berthing.- Biography :...
- Docking system agreement key to global space policy – Oct. 20, 2010