The Shenzhou-VI spaceship remains to be a three-cabin structure -- a propulsive cabin, a return cabin and an orbital cabin, the appearance and structure of the entire spaceship are same as the Shenzhou-5, its weight is basically kept at about eight tons, according to Zhang Bainan, chief architect of China's manned spacecraft system.
After entering the orbit, the spaceship first flies five circles on an oval track at 200-km nearby point and 350-km distant point, and then changes over to a round track 343 km away from the ground, it takes 90 minutes to complete the flight of a circle round the earth, the flight path, when projected to the ground, presents a sinusoidal curve pushing eastward continually. Its orbital performance is same as the Shenzhou-5 spaceship.
In addition, more than 40 pieces of equipment and six pieces of software are added to the spaceship, so that the spaceship has over 600 pieces of equipment, 82 software and over 100,000 components.
Four major improvements from Shenzhou-5 spacecraft
Architect Zhang says: Based on Shenzhou-5, Shenzhou-VI spaceship keeps the main technical characteristics intact and makes 110 items of technical improvement in four aspects in compliance with the needs of the task of two-men and multiple-day flight and the development of individual technologies.
1. Improvement made round the task of two-men, multiple-day flight. First, adequate and even more-than-needed consumer goods, including food, water and sleeping bags, are prepared for the astronauts. Second, the cabin's environmental control ability is enhanced. Oxygen, temperature and humidity in the cabin can be automatically induced and regulated.
2. Improvement to the use of the orbital cabin's functions. Placed in this cabin are many daily necessities for the astronauts, such as food heating device and tableware. A sleeping bag is hung in the orbital cabin for the two astronauts to take rest by turn. Besides, there is also a special cabinet for clean articles in the orbital cabin; a device for collecting excrement and urine is put to use for the first time.
3. Improvement made for the safety of astronauts. The landing buffer function is designed for the astronaut's chair in the return cabin. This is aimed to ensure the astronaut's safety when trouble occurs to the thrust rocket. The Shenzhou-VI spaceship has redesigned the buffer, and repeated experiments have been made in connection with the entire spaceship, and each of the three experiments of throwing the buffer down from a high tower and the airplane is successful.
4. Continual improvement. Shenzhou-VI spaceship has some daily continual improvements made to components and raw and processed materials. For instance, the "black caskets�� from Shenzhou-1 to Shenzhou-VI were developed in 1994, the storage capacity was only 10 megabyte, not only the storage capacity of present black casket is 100-fold greater than the original, but the write-in and read-out speed of data is also over 10-fold higher than the original, and its volume is less than half of the original.
Detailed annotation of the internal environment of Shenzhou-VI spaceship
In the flight of Shenzhou-5 spaceship, the environmental control and life security system can only be regarded as an experiment, only this time the environmental control and life security system is put into real use as part of the task of Shenzhou-VI spaceship.�� Fu Lan, former chief designer of the environmental control and life security sub-system of the Shenzhou-VI spacecraft, says, "Our task is to do our best to create a more comfortable living space for the astronauts.�� Air quality in the cabin is kept at above the super-level.
Fu Lan said that Shenzhou-VI and Shenzhou-5 both use the same air-supply voltage-regulating system, oxygen and nitrogen are carried into the spaceship by high-voltage cylinders, the air is released through a control valve, so that the air in the cabin is about the same as that on the ground.
Shenzhou-VI spaceship carries about 50 kg of oxygen, not only is capable of meeting the needs of the two astronauts for several days, but also is enough for emergency use. At the same time, the advanced ventilation and purifying system in the spaceship can timely remove various kinds of dust and foreign substance in the air, so that air quality can always be kept at and above the excellent grade. Temperature and humidity make people feel quite comfortable, through the temperature and humidity control system, the temperature in the return cabin of Shenzhou-VI spaceship is kept between 17-25 degrees C, and relative humidity between 30-70 percent.
"This is a quite comfortable environment." Fu Lan says: Temperature in the cabin is controlled mainly by special air-conditioning. The working condition of the air-conditioner is automatically adjusted in light of the change of the astronaut's activity volume and the degree of sun shining over the spaceship. At the time of the return of the spaceship, even if the exterior temperature of the spaceship reaches several thousand degrees C due to intense friction with the atmosphere, the temperature in the return cabin still remains at about 25 degrees C.
Compared with humidity control, temperature control is far more difficult. According to Fu Lan, through the normal metabolism of daily breathing and perspiration of each astronaut in the outer space, about 1.8 kg of moisture will be produced. Shenzhou-VI uses a kind of absorption aperture membrane to get the air through by applying certain pressure while the water is absorbed. When this membrane is used in an air circulating system, it is possible to effectively filter the moisture in the air and keep the humidity in the spaceship at a relatively stable level. Facilities related to all aspects of livelihood are complete. Fu Lan said that at dining time, the astronauts put their food on a service plate with magnetic absorption function, they use knives and forks to take their food. In the outer space, astronauts can use heaters to warm up their food. While drinking, the astronauts can link their mouths up with the drink container through a suction pipe in the size of a pencil and, through applying a certain pressure on an air pump, the drink will then stream into the mouths of the astronauts.
A system is installed for the collection of the astronauts' excrement and urine. "This is a system equivalent to a dust catcher," said Fu Lan. When the system is being used, it will collect the discharge, which will later be disposed of separately. At the same time, active carbon is used as absorbent for deodorization.
Long March-2F rocket used for the launch
Shenzhou-VI spaceship will use Long March-2F rocket for the launch. The Long March-2F rocket is a carrier rocket developed on the basis of the Long March-2E, i.e., the Long March-2 cluster rocket, which presently is China's only rocket used for the launching of manned spaceships.
The rocket, 58.3 meters in length and 479.8 tons in weight, is composed of four liquid rocket boosters and grade 1 and grade 2 chips, cowling, and an escape frame, and consists of 10 subsystems including a control system, trouble-detecting system, remote metering system, external security checking system, escaping system, the rocket structure, dynamical system, propellant usage system, auxiliary system and ground facilities.
The Long March-2F rocket, with its reliability index reaching 0.97, and astronaut's safety index touching 0.997, is a carrier rocket with most complicated technology, highest reliability and security indexes in China's aerospace history. The rocket can securely and reliably send the spaceship into the preset orbit, at the same time, before the spacecraft flies out of the atmospheric layer, if major trouble occurs, the rocket can deliver the astronauts safely out of the dangerous district in accordance with life requirement.
Thus far, the Long March-2F rocket has successfully sent four unmanned spaceships and Shenzhou-5 manned spaceship into the pre-determined orbit, with the successful launching rate reaching 100 percent.
According to Liu Yu, general director of the carrier rocket system for the manned space flight project, compared with the Shenzhou-5 manned spaceship, 75 items of technology were changed in the rocket used for the present launch, thus further enhancing reliability, security and improving riding comfort.
By People's Daily Online