The orbital module was jettisoned before retrofire and was equipped with its own solar panels and propulsion for autonomous flight after separation. At a later phase of the project the module could be left in space as a docking target, man-tended laboratory or attached to the planned 20-metric ton space station. For such missions it would have a Russian-style androgynous docking system at the forward end of the orbital module in place of the equipment pallet.
The module was a semi-monocoque aluminum structure, cylindrical, 2.250-m in diameter and 2.800 m long. This length did not include an equipment pallet mounted on the forward end, which varied from flight to flight. A large 80-cm-diameter EVA hatch was located in the lower portion of the module, with a 48-cm diameter porthole above that, very unlike Soyuz. A rectangular equipment package was mounted on the opposite side of the orbital module. Also on that side was a second smaller window. The lateral sides of the module were used for mounting of the rotating solar panels. At the base of the orbital module was a 70-cm-diameter hatch providing access to the re-entry vehicle. Presumable a similar hatch would be located at the nose for docking missions.
The equipment pallet varied from mission to mission. Shenzhou 1 and 2 flew with dummy or partial electronic intelligence packages, a complex arrangement of equipment mounted at the top of the orbital module. This included a semi-circular ring which provided mounting for rectangular instruments around its exterior. Three perpendicular 0.4 m extendible booms were deployed as well, part of an experimental magnetic attitude sensing and control system. Shenzhou 3 and 4 flew with the complete electronic intelligence payload mounted on the nose. As analyzed by veteran space-radio expert Sven Grahn, this consisted of two major components. UHF emission direction-finding was accomplished by three earth-pointing television-aerial type antennae deployed on long telescoping booms. These would function in the UHF band between 300 and 1,000 MHz, covering a variety of civilian and military emission sources. They were supplemented by seven horn antennae arranged in an arc. These would detect and localize radar transmissions. This combination would allow coverage of the entire earth below as the orbital module passed over the earth's surface.
Given that China had not previously flown a major ELINT satellite, this was an enormous leap in Chinese military surveillance from space. Each orbital module remained in space as long as eight months after the other modules return to earth. That means the orbital modules of the Shenzhou spacecraft have been scanning the earth 90% of the time, day in and day out, since Shenzhou 3 was launched in March 2002. Data was dumped in ten-minute bursts when the spacecraft pass over Miyun, near Beijing. These missions would have given China's equivalent to the American National Security Agency an excellent introduction into capabilities and problems in flying an operational ELINT satellite over a variety of targets and seasons of the year. The main objective, as was the case for low-altitude Soviet systems, would be to keep track of the US Navy, particularly carrier groups. Observations by Shenzhou 4 during the Iraq War would have been an intelligence windfall for the Chinese.
Shenzhou 5's equipment included an imaging reconnaissance package. This consisted of two cameras with an aperture of 500 - 600 mm. The close-look camera was mounted in the equipment pallet at the nose of the spacecraft in a rectangular housing, 0.900 m x 1.268 m x 0.86 m. Zhang Houying of the Chinese Academy of Sciences gave the ground resolution of this close-look CCD camera as 1.6 m. The other camera was mounted in the porthole above the orbital module's main hatch. The use of two differing cameras indicated a hyper-spectral, multi-resolution, combination mapping/close-look system.
Drawings also appeared of a curious Shenzhou configuration with 'jaws' at the forward end of the orbital module, perhaps some kind of satellite capture mechanism.
A Central Terminal Unit in the orbital module was a dual-redundant computer that controlled the spacecraft during autonomous flight. It would also automatically come on line if the primary system in the re-entry vehicle failed during manned operations. The orbital module's autonomous on-orbit tracking and control subsystem consisted of S-band transponders, telemetry equipment and antennae. Thermal control of the module was via external louvers. Orbital module power was provided by two solar panels, each in two section, with a total area of 12.24 square meters. These charged nickel-cadmium batteries within the module for power when in the earth's shadow.
Four groups of four 5-N thrusters were mounted at the base of the orbital module. These provided an autonomous attitude control and maneuvering capability to the orbital module when in free flight. They also presumably could serve as a backup to the main orientation system in an emergency. The system used hydrazine monopropellant, pressure-fed at 23 Mpa from a 7-litre titanium cold gas tank. The thrusters were plumbed into redundant groups.
Many, many thanks to Chen Lan for providing original Chinese-language source material for this project, and to WXJ for the translation.
Habitable Volume: 8.00 m3. RCS Coarse No x Thrust: 16 x 5 N. Electric System: 1.20 kWh. Electric System: 0.50 average kW.
Gross mass: 1,500 kg (3,300 lb).
Height: 2.80 m (9.10 ft).
Diameter: 2.25 m (7.38 ft).
Span: 10.40 m (34.10 ft).
First Launch: 2003.10.15.
Number: 1 .