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The Chinese Shenzhou manned spacecraft resembles the Russian Soyuz spacecraft, but is of larger size and all-new construction. Like the Soyuz, it consists of a forward orbital module, a reentry capsule, and an aft service module. Unlike the Soyuz, the orbital module is equipped with its own propulsion, solar power, and control systems, allowing autonomous flight. Shenzhou will be used to develop manned space flight techniques (extravehicular activity, rendezvous and docking) and later serve as a ferry to Chinese space stations. Like Soyuz, derivatives could be used as a lunar orbital and landing spacecraft.
The Shenzhou project received limited funding, resulting in a protracted development program. Work began in 1992, with annual unmanned flights finally beginning in the winter of 1999/2000. The first manned flight came in the autumn of 2003. Shenzhou in launched by the man-rated CZ-2F launch vehicle from the Jiuquan Satellite Launch Center.
First launch: 19-Nov-1999; first manned flight 15-Oct-2003 (Shenzhou 5)
Number manned launches: 2 to end-2005
Principal uses: LEO solo operations, space station ferry
Performance: typical orbit 196 x 324 km, 42.5o inclinaton
Principal units: forward Orbital Module (OM), center Reentry Vehicle (RV), and aft Service Module (SM)
Overall length: 9.25 m
Habitable volume: 14.0 m3
Launch mass: 7,840 kg
Life support systems: The environment control system regulates supply of nitrogen and oxygen to control the cabin pressure, circulates and purifies the cabin air, controls the cabin temperature and humidity, and includes smoke and fire monitoring and removal provisions. The system keeps the cabin atmosphere at 800-1000 mbar, oxygen partial pressure at 200-240 mbar, humidity at 30-70%, and temperature at 17-25oC. During reentry cabin temperature can go up to 40oC. There is a spacesuit loop for keeping the crew alive using umbilicals connected to their spacesuits in case of cabin depressurization. The system is fed by steel alloy nitrogen and oxygen gas bottles, at a pressure of 21 MPa, located in the SM. A separate supply of gas bottles are mounted in the RV cabin for emergencies and during reentry.
Avionics/control: The guidance system determines spacecraft attitude and position using digital and analogue sun sensors, infrared horizon sensors, a strap-down inertial measurement unit, and a global positioning system receiver, all feeding triple-redundant majority-voting computers. Normally the spacecraft would be oriented and maneuvered automatically. However in the event of a system failure, the crew can manually orient the spacecraft using the Vzor device and hand controllers, and manually command and time retrofire. The computers are loaded with Chinese-developed software using novel techniques for control of the booster during ascent, in-orbit update and alignment of the inertial platform, and automated diagnosis and self-repair in case faults are detected.
The reentry vehicle is conceptually based on the Soyuz, but is not a copy. The Shenzhou capsule is about 1/7th larger dimensionally than Soyuz and, therefore, cannot use Russian hardware, but is instead a scaled-up copy of the Soyuz 'headlight' aerodynamic form. The structure of the reentry vehicle uses a titanium frame, with aluminum alloy sidewalls, base, and pressure vessel. The crew enters and exits through an approximate 70 cm diameter hatch at the top of the capsule. Two small portholes, about 30 cm in diameter, provide a limited outside view.
Crew size: 3 max
Endurance: 20 days
Length: 2.50 m
Principal diameter: 2.52 m
Habitable volume: 6.0 m3
Total mass: 3,240 kg (heat shield 450 kg)
Reaction control system
thrusters: 8 x 150 N (activated for reentry only)
propellant: hydrazine, 28 kg
L/D hypersonic: 0.30
Power: small battery supply for power after SM separation
Landing system: At an altitude of 10 km the parachute hatch is jettisoned and two pilot parachutes deployed. These pull out the drogue parachute, followed by the ring-sail main parachute that has an area of 1200 m2 and a mass of 90 kg. A back-up parachute with an area of 760 m2 is provided. Below 6 km altitude the heat shield is jettisoned, exposing a gamma ray altimeter and the four nozzles of the soft-landing retrorockets. As the capsule approaches the ground, the capsule converts from single-point to two-point suspension under the main parachute, and its vertical velocity declines to 8 m/s. The altimeter ignites four solid propellant retrorockets at one meter above the ground, reducing final impact velocity to 3.5 m/s. In case of failure, the crew seats are fitted with shock absorbers to guarantee a survivable landing.
The orbital module provides quarters for the crew during a space mission and can be fitted out with different internal and external equipment according to mission requirements. The orbital module is jettisoned before retrofire and is equipped with its own solar panels and propulsion for autonomous flight after separation. At a later phase of the project, the module may be left in space as a docking target, man-tended laboratory, or attached to a space station. For such missions it would have a docking system at the forward end of the orbital module in place of the equipment pallet.
Endurance: 200 days
Length: 2.80 m (excluding forward equipment pallet)
Principal diameter: 2.25 m
Maxium span: 10.40 m
Habitable volume: 8.0 m3
Total mass: 1,500 kg
Reaction control system
thrusters: 16 x 5 N
Power: 2 solar panels, 12.24 m2 total area, 0.50 kW average, 1.2 kWh
The service module provides the electrical power, attitude control, and propulsion for the spacecraft in orbit. It is the same form as that of Soyuz, but longer, wider, and the flared base is less pronounced. The bottom portion of the module is used as an external radiator surface for the spacecraft's thermal control system. Two solar panels are deploy from the sides of the service module and can be rotated to obtain maximum solar insolation regardless of spacecraft attitude. Roll and translation attitude control thrusters are arranged at the forward end of the service module. Within the flared base of the module a unique arrangement of thrusters (firing from the outer rim of the flared base toward the central axis of the spacecraft) control pitch and yaw.
Endurance: 20 days
Length: 2.94 m
Principal diameter: 2.50 m (flaring to 2.80 m at aft end)
Maxium span: 17.00 m
Total mass: 3,000 kg
Propellant mass: 1,000 kg (supplies main engine + RCS)
main engine thrust: 10 kN vac
specific impulse: 290 s vac
RCS thrusters: 8 x 150 N + 16 x 5 N
Power: 2 solar panels, 24.48 m2 total area, 1.00 kW average, 2.4 kWh
LAUNCH ESCAPE SYSTEM
The escape tower will fire to pull the Shenzhou capsule and orbital module away from the booster in the event of a major booster malfunction from 15 minutes before launch to the point of payload fairing jettison at T+160 seconds. The system consists of the escape tower, the upper portion of the payload fairing, and the orbital and reentry modules. This complete assembly has a total mass of 11,260 kg, and is 15.1 m long and 3.8 m in diameter. The system is designed for a reliability of 0.995. The tower itself is 8.35 m long and equipped with six solid propellant motors. These consist of four axial vernier motors, a low altitude separation motor with eight nozzles, and a medium altitude escape motor with four nozzles. In the upper shroud are four motors used for escape at high altitude, and two motors used for shroud separation. Four grid-like aerodynamic flaps on the upper shroud stabilize the assembly during an abort.