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.
The emergency flight profile
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.
Before departure from the station, the crew conducts tests of the motion control system onboard Soyuz. After the crew boards the vehicle and closes the hatches, the undocking takes place. Only after few hours in a solo flight, the Soyuz orients itself tail first and the braking engine burn is initiated.
After deorbiting burn is completed, an external cable lines connecting three main modules of the spacecraft and six petals of the thermal protection layers are shed. The habitation module and instrument module then separate from the reentry capsule. The capsule carrying the crew than lands under a parachute.
Under a nominal flight, the reentry capsule under its main parachute enters a stable descent with the speed of around 6-7 meters per second. Solid-propellant engines then fire moments before touchdown reducing impact speed to 1.5 meters per second. In case of landing under a spare parachute, the descent speed could reach as high as 9.5 - 10.5 meters per second.
Some eight minutes after the firing of soft-landing engines, an automated command is issued to jettison the cap covering the housing of the ABM-279 antenna. Alternatively, the same command can be issued by the crew.
Page author: Anatoly Zak
Last update: December 13, 2017
Copyright © 2010 RussianSpaceWeb.com
Animation of the Soyuz TM spacecraft deploying its solar panels and antennas upon reaching the orbit. (QuickTime: 4 sec / 2.3 MB)
Animation of the Soyuz TM spacecraft conducting braking maneuver before landing. (QuickTime: 8 sec/3.3 MB)
Animation of the Soyuz TM spacecraft's reentry vehicle separating from habitation and instrument modules. (QuickTime: 8 sec / 1.2 MB)
Animation of the Soyuz capsule reentering the Earth atmosphere. (QuickTime: 4 sec / 484 K)