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Space rendezvous

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Space Shuttle Atlantis connected to Russia's Mir Space Station

space rendezvous between two spacecraft, often between a spacecraft and a space station, is an orbital maneuver where the two arrive at the same orbit, make their orbital velocities the same, and bring them together (an approach maneuver, taxiing maneuver); it may or may not include docking.

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[edit]Historic rendezvous

Gemini 7 photographed from Gemini 6

On August 12, 1962 Vostok 3 and Vostok 4 were placed into nearby orbits and passed within several kilometers of each other, but did not have the orbital maneuvering capability to perform a space rendezvous. This was also the case on June 16, 1963 when Vostok 5 and Vostok 6 were launched into nearby orbits. G. Salakhutdinov, in a Russian periodical from 1990[1], relates the following quote:

"The group flight ... well, a day after the launch, the first craft was over Baykanur. If the second craft were launched now with great precision, then they would turn out to be next to each other in space. And that's what was done ... The craft turned out to be 5 kilometers from each other! Well, since, with all of the secrecy, we didn't tell the whole truth, the Western experts, who hadn't figured it out, thought that our Vostok was already equipped with orbital approach equipment. As they say, a sleight of hand isn't any kind of fraud. It was more like our competitors deceived themselves all by their lonesome. Of course, we didn't shatter their illusions." — First Deputy Chief Designer Vasily Mishin

The first space rendezvous took place on December 15, 1965, when Gemini 6A maneuvered within 30 cm of the passive Gemini 7. Astronaut Wally Schirra accomplished the task. The spacecraft were not equipped to dock and no physical contact took place. Schirra later commented that

"Somebody said ... when you come to within three miles (5 km), you've rendezvoused. If anybody thinks they've pulled a rendezvous off at three miles (5 km), have fun! This is when we started doing our work. I don't think rendezvous is over until you are stopped - completely stopped - with no relative motion between the two vehicles, at a range of approximately 120 feet (37 m). That's rendezvous! From there on, it's stationkeeping. That's when you can go back and play the game of driving a car or driving an airplane or pushing a skateboard — it's about that simple."[2]

The first space rendezvous with docking took place on March 16, 1966, when Gemini 8, under the command of Neil Armstrong, rendezvoused and docked with the uncrewed Agena 8 target vehicle.

The Soviets carried out the first automated (and unmanned) space docking between Cosmos 186 and Cosmos 188 on October 30, 1967.[3]

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 rendezvous and docking of three spacecraft took place when both Soyuz 26 and Soyuz 27 were docked to the Salyut 6space station during January 1978.

[edit]Uses

A frequent use of space rendezvous has been the transportation of crew and supplies to orbiting space stations. The first of these was the rendezvous and docking on 7 June 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 both Soyuz spacecraft and Space Shuttles 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[4] 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 Modulewould 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 overorbital 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 thrusters[1]

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 spacecraft, a maneuver known as transposition, docking, and extraction was performed an hour or so after Trans Lunar Injection of the sequence third stage of the Saturn V 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 weapons partly fall under the category of hostile rendezvous. Kinetic projectiles do not use explosives or radiation, but just collide.

[edit]Methods

This section requires expansion.

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, and ISS programs. The active vehicle is first 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 (0.030 m/s) to 0.2 ft/s (0.061 m/s).[5]

Z-bar approach
V-bar approach

STS-104 was the third Space Shuttle mission to conduct a V-bar arrival at the International Space Station.[6] 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-2docking port.[7]

R-bar approach

Astrotech has proposed meeting ISS cargo needs with a vehicle which would approach the station, "using a traditional nadir R-bar approach."[8]

[edit]References

  1. ^ G. Salakhutdinov, "Once more about space, interview with Academician Vasiliy Pavlovich Mishin former chief designer of rocket-space equipment" (English title), Ogenek 34 (August 18-25 1990):4-5.
    Translation at http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20000088626_2000122281.pdf , page 379.
  2. ^ On The Shoulders of Titans - Ch12-7
  3. ^ NSSDC ID: 1967-105A NASA, NSSDC Master Catalog
  4. ^ Bryan Burrough, Dragonfly: NASA and the crisis aboard Mir, (1998, ISBN 0-88730-783-3) 2000, ISBN 0-06-093269-4, page 65, "Since 1985 all Russian spacecraft had used the Kurs computers to dock automatically with the Mir station" ... "All the Russian commanders had to do was sit by and watch."
  5. ^ "TRACK AND CAPTURE OF THE ORBITER WITH THE SPACE STATION REMOTE MANIPULATOR SYSTEM" (PDF). NASA.
  6. ^ "STS-104 Crew Interviews with Charles Hobaugh, Pilot". NASA.
  7. ^ WILLIAM HARWOOD (March 9, 2001). "Shuttle Discovery nears rendezvous with station". SPACEFLIGHT NOW.
  8. ^ Johnson, Michael D.; Fitts, Richard; Howe, Brock; Hall, Baron; Kutter, Bernard; Zegler, Frank; Foster; Mark (18 September 2007). "Astrotech Research & Conventional Technology Utilization Spacecraft (ARCTUS)" (PDF). AIAA SPACE 2007 Conference & Exposition. Long Beach, California. pp. p. 7.

[edit]See also

[edit]External links

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