Chinese space officials have claimed all along that the Descent Module of Shenzhou is the largest among similar capsules from the former Soviet Union and the U.S. However, there has been scant official information on the dimensions of the Shenzhou spacecraft and the CZ-2F rocket.

In appearance, the Shenzhou-3 (SZ-3) spacecraft looks the same as its two predecessors. But on the SZ-3 mission, there are more systems installed and tested than the two previous flights.

The focus of the SZ-3 mission is to test systems that would ensure the safety of yuhangyuans ("astronauts").

This includes assessing the functionality, reliability and safety of each manned spaceflight system; coordination among different systems; the spacecraft environment for manned flight; the effectiveness of the improved measures that have been implemented; the escape and emergency life support systems; and the capability of the launcher's redundant control system. Testing of spacecraft application projects is also on the mission.

Space officials have said that Shenzhou can carry out primary missions lasting longer than 20 days.

The 7.8-tonne (7,800-kg) Shenzhou spacecraft has three sections: an Orbital Module, a Descent Module, and a Propulsion Module.

The forward section of Shenzhou is the Orbital Module where yuhangyuans ("astronauts") live and work in space as well as a payload storage area.

The module is 2.8 meters long with a diameter of 2.25 meters. At both ends of the module are access hatches where yuhangyuans can enter the adjacent Descent Module or a space station.

Attached to the exterior of the module is a pair of deployable solar array of 12 squared meters, solar sensors, communications antennae, and docking structures.

Many of the science experiments, including those of life and material sciences, are mounted in the Orbital Module that will stay in orbit for about six months after the Descent Module returns to Earth.

The middle section of the spacecraft is the tightly sealed Descent Module where yuhangyuans sit during ascent and reentry. At the front of the module is a hatch through which yuhangyuans enter the Orbital Module next door.

The Descent Module is 2.059 meters long with the largest diameter at the base at 2.5 meters. The entire exterior surface is covered with ablation material, which forms the heat shielding structure of the module.

There are three reclining seats in the Descent Module. Forward to the lower end of the seats are instrument panels, a hand controller and an optical sight.

SZ-3 under final assembly in the main Vehicle Assembly Building at the Jiuquan Satellite Launch Centre (JSLC) in northwestern province of Gansu

On this mission a dummy occupies one of the seats. The dummy is installed with physiological sign equipment that simulates physiological activity parameters of a yuhangyuan in space, such as palpitation, pulse, breathing, eating, metabolism, and excretion. Ground controllers control and monitor all aspects of this experiment.

Also installed in the Descent and Orbital Modules are medical facilities and in-cabin radiation and environment monitoring facilities, which collect data on the radiation level and atmospheric composition, temperature, pressure and humidity.

Shenzhou's aft section is the Propulsion Module which houses various engines. The module is 2.94 meters long with the widest diameter of 2.8 meters. On the outside of the module is a pair of deployable solar array of 24 squared meters.

Mission controllers are monitoring the performance of the two sets of solar arrays closely, particularly the experiment which combines electrical output from the arrays with that from other batteries in an integrated power supply network.

Although Chinese space officials acknowledge that Shenzhou is modeled after the Russian Soyuz spacecraft, they insist that Shenzhou is truly a native space vehicle.

The Chinese Academy of Space Technology (CAST), an affiliated institution of the China Aerospace Science and Industry Corporation (CASIC), has the overall responsibility of the Shenzhou project. CAST along with the Shanghai Academy of Spaceflight Technology (SAST, formerly known as the Shanghai Bureau of Astronautics) and the Aerospace Medical Engineering Research Institute jointly design and develop the spacecraft.

New Launch Escape System Tested

According to the CASIC affiliated institution Chinese Academy of Launch Vehicle Technology (CALT), which designs and develops CZ-2F, the escape tower enables yuhangyuans to bail out an emergency of a major malfunction -- from 15 minutes before launch to moments before the payload fairing jettison at about 160 second after liftoff.

The Changzheng-2F (CZ-2F, or Long March-2F) launcher is a human-rated modification of CZ-2E, a launcher with strap-on boosters in the Changzheng family.

CZ-2F consists of two core stages, a payload fairing, an escape tower, and four liquid-fuel strap-on boosters. The total length of the launch vehicle is 58.34 meters. The liftoff mass of the CZ-2F on this mission, its third flight, is 479.7 tonnes (479,700 kg).

There are ten subsystems on CZ-2F: launcher structure, control system, power equipment, fault monitoring management system, escape system, remote monitoring system, safety external monitoring system, propellant utilization system, auxiliary system, and ground facilities.

The fault monitoring management system and the escape system are added to ensure the safety of yuhangyuans and are unique to CZ-2F.

To accommodate satellite deployment, CZ-2F preserves the interface and installation location of the payload attitude orientation system.

According to the CASIC affiliated institution Chinese Academy of Launch Vehicle Technology (CALT), which designs and develops CZ-2F, the escape tower enables yuhangyuans to bail out an emergency of a major malfunction -- from 15 minutes before launch to moments before the payload fairing jettison at about 160 second after liftoff.

The launch escape system is composed of the escape tower and the upper portion of the payload fairing. Combining the Orbital and Descent Modules with the escape system forms the escape vehicle for the yuhangyuans. The system is designed with a reliability of 0.995.

Coupled with the two modules, the entire length of the launch escape system/vehicle is 15.1 meters, with the widest diameter of 3.8 meters, and a total weight of 11.26 tonnes (11,260 kg).

When the fault monitoring management system on CZ-2F senses an emergency situation, it automatically activates the launch escape system. Ground controllers can also activate the system when necessary.

On SZ-3 two manual activation systems are added, one system each for ascent and reentry. These systems allow yuhangyuans to manually activate the escape system in case the automatic mode malfunctions.

The launch escape system is installed and tested on this mission for the first time. Shortly after the CZ-2F lifted off, the announcement "escape tower separation" was heard over the public broadcast system at JSLC and all control centres. Space officials have not commented on how successful the test is.

The escape system was not installed on SZ-2 in order to prevent faulty signals that might trigger its deployment in an otherwise nominal ascent.

A successful test of the escape system is crucial to the progress of the manned space project. A space official said, "If this critical juncture is not passed, manned spaceflight cannot be realized."

Related Links
SpaceDaily
Search SpaceDaily
Subscribe To SpaceDaily Express

Thanks for being here; We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor $5 Billed Once credit card or paypal		SpaceDaily Monthly Supporter $5 Billed Monthly paypal only