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The Soyuz flight profile From 1971 and well into the 21st century, the Soyuz spacecraft's main role in the Russian space program was to deliver crews to space stations in the low-Earth orbit.
Several modifications of the 310-ton, 51.3-meter Soyuz rocket have been used to insert the Soyuz spacecraft into orbit. During launch and the atmospheric phase of the ride to orbit, the Soyuz spacecraft is completely covered by a payload fairing. In turn, the payload fairing is topped by an emergency escape system. In case of emergency on the launch pad or early in flight, when the explosion of the rocket booster is most likely, the solid-propellant emergency escape system is designed to save the crew. The orbital flight The Soyuz TM and TMA models could remain in space up to 200 days, when docked to the station and it could orbit the Earth in the autonomous flight for 4.2 days. In case of emergency on the station, the Soyuz can be sent up unmanned or piloted by a single cosmonaut to serve as a lifeboat; or be used as an unmanned cargo ship to return 250 kilograms from orbit. The nominal autonomous flight would normally be split into two phases: a 2.2-day period spent from launch to docking with the station, and a several-hour long period from undocking to landing with a built-in reserve of two days. Number of external elements, including solar arrays, antennas and sensors placed in folded position during the launch and deployed shortly after the separation of the spacecraft from the third stage of the launch vehicle. During the second orbit after the launch, the crew and ground controllers usually conduct tests of radio rendezvous, communication, TV and motion control systems. During the autonomous flight the spacecraft can be sent into a spin with its solar panels facing the Sun, to maximize the power input. Rendezvous and docking In most missions, the Soyuz TM and TMA spacecraft follow a two-day rendezvous profile to reach the space station. Practically entire process of rendezvous is conducted in automated mode. Upon reaching a range of 150 meter (plus minus 50 meters) range from the station, the Soyuz enters a stationkeeping mode within the radio coverage zone of the Russian ground tracking stations. The final approach and docking then begins as flight controllers at the Russian mission control in the town of Korolev, northeast of Moscow, monitor the entire process live with the help of TV imagery and telemetry data. As a backup option, the commander onboard the Soyuz can conduct berthing manually. Upon docking, the crew conducts leak tests and then can open hatches into the space station. After docking, many systems onboard Soyuz can be deactivated. Perhaps the riskiest and scariest part of the Soyuz flight comes at the very end, with the fiery reentry into the atmosphere, followed by a rough touchdown, which, according to many crew members who have experienced it, can only nominally be called soft.
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