A rendezvous takes place each time a spacecraft brings crew members or supplies to an orbiting space station. The first spacecraft to do this was the ill-fated Soyuz 11, which successfully docked with the Salyut 1 station on June 7, 1971. Human spaceflight missions have successfully made rendezvous with six Salyut stations, with Skylab, with Mir and with the International Space Station (ISS). Currently Soyuz spacecraft are used at approximately six month intervals to transport crew members to and from 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 flies to a close rendezvous and maintains station-keeping without docking, allowing the ISS Canadarm2 to grapple it and berth it to the station.
Space rendezvous has 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 thrusters.
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
Read more about this topic: Space Rendezvous