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Chinese space station

Drawing of Shenzhou and Cargo ship docked to the CSS
Station statistics
Crew	3
Launch	2020's
Launch pad	Wenchang Satellite Launch Center
Mass	over 60,000 kg
Length	approx 36 m
Width	approx 32 m
Height	approx 5-28 m (dependent upon future modules)
Atmospheric pressure	1 atm
Periapsis altitude	340 to 450 km
Apoapsis altitude	340 to 450 km
Orbital inclination	42 to 43 degrees
Typical orbit altitude	340 to 450 km
Orbital speed	approx 28,000 km/h
Orbital period	approx 90 minutes
Orbits per day	approx 15
Days in orbit	0
Days occupied	0
No. of orbits	0

The Chinese space station (CSS) is a planned artificial satellite to be placed in low earth orbit. Built and launched entirely by the People's Republic of China (PRC), it shall combine indigenous designs with international compatibility. It is part of Project 921 of the Chinese space program. It is a third generation modular space station, comparable to the Soviet/Russian Mir, Russian OPSEK and the ISS. Operations will be controlled from the Beijing Aerospace Command and Control Center in the People's Republic of China.

Purpose

The CSS will inspire people everywhere, Wang Wenbao, director of the Chinese space agency (CSME), reckons "This major project will enhance national prestige and strengthen the national sense of cohesion and pride." Jiang Guohua says, "We will adhere to the policy of opening up to the outside world". "Scientists of all countries are welcome to participate in space science experimental research on China's space station." Guohua is an engineer at the China Astronaut Research and Training Center.

The CSS will improve researchers ability to conduct science experiments in freefall (Zero-gravity) and the space environment, beyond the duration offered by China's unmanned artificial satellites and man-tended modules. Individual experiments will not require their own orbital launchers, but can be sent to the station on robot spacecraft, and be conducted by long-term crews.

Experience gained in the operation of the station and in human health research can be applied to interplanetary and deep-space missions.

Origins

After the United States threatened to use nuclear weapons during the Korean War, Chairman Mao Zedong decided that only a nuclear deterrent of its own would guarantee the security of the newly founded PRC. Thus, Mao announced his decision to develop China's own strategic weapons, including associated missiles. After the launch of mankind's first artificial satellite, Sputnik 1 by the Soviet Union on October 4, 1957, Chairman Mao decided to put China on an equal footing with the superpowers (“我们也要搞人造卫星”), using Project 581 with the idea of putting a satellite in orbit by 1959 to celebrate the 10th anniversary of the PRC's founding.

Past Sino-Soviet co-operation

During the cordial Sino-Soviet relations of the 1950s, the USSR engaged in a cooperative technology transfer program with the PRC under which they taught Chinese students and provided the fledgling program with a sample R-2 rocket.

The first Chinese missile was built in 1958 reverse-engineered from the Soviet R-2, itself an upgraded version of the German V-2 rocket. But when Soviet premier Nikita Khrushchev was denounced as revisionist by Mao, the friendly relationship between the two countries turned to confrontation. As a consequence, all Soviet technological assistance was abruptly withdrawn after the 1960 Sino-Soviet split.

Post Sino-Soviet split

Mao and Zhou Enlai decided on July 14, 1967 to begin the PRCs crewed space program. China's first manned spacecraft design was named Shuguang-1 (曙光一号) in January 1968.

The Chinese DF-4 was used to develop the Long March-1 SLV. A newly-designed spin-up orbital insertion solid propellant rocket motor third stage was added to the two existing Nitric acid/UDMH liquid propellant stages. An attempt to use this vehicle to launch a Chinese satellite before Japan's first attempt ended in failure on November 16, 1969. In 1966, China tested its first indigenously developed DF-3 IRBM with success. The second satellite launch attempt on April 24, 1970 was successful. A CZ-1 was used to launch the 173 kg Dong Fang Hong I (东方红一号 (meaning The East Is Red I), also known as Mao-1 and it was the heaviest first satellite placed into orbit by a nation. The PRC's second satellite was launched on March 3, 1971. The 221 kg ShiJian-1 was equipped with a magnetometer and cosmic-ray/x-ray detectors.

Project 714 was officially adopted in April 1971 with the goal of sending two astronauts into space by 1973 aboard the Shuguang spacecraft. The first screening process for astronauts had already ended on March 15, 1971, with 19 astronauts chosen. The program was soon cancelled due to political turmoil.

Further development of the Long March rocket series allowed the PRC to initiate a commercial launch program in 1985, which has since launched over 30 foreign satellites, primarily for European and Asian interests.

The next crewed space program was even more ambitious and was proposed in March 1986 as Project 863. This consisted of a crewed spacecraft (Project 863-204) used to ferry astronaut crews to a space station (Project 863-205). Several spaceplane designs were rejected two years later and a simpler space capsule was chosen instead. Although the project did not achieve its goals, it would ultimately evolve into the 1992 Project 921 project, taking in the Shenzhou program, the Tiangong program, and the CSS.

Sino-Russian cooperation resumed

In 1994, Russia sold some of its advanced aviation and space technology to the Chinese. In 1995 a deal was signed between the two countries for the transfer of Russian Soyuz spacecraft technology to China. Included in the agreement was training, provision of Soyuz capsules, life support systems, docking systems, and space suits. In 1996 two Chinese astronauts, Wu Jie and Li Qinglong, began training at the Yuri Gagarin Cosmonaut Training Center in Russia.

After training, these men returned to China and proceeded to train other Chinese astronauts at sites near Beijing and Jiuquan. The hardware and information sold by the Russians led to modifications of the original Phase One spacecraft, eventually called Shenzhou, which loosely translated means “divine vessel.” New launch facilities were built at the Jiuquan launch site in Inner Mongolia, and in the spring of 1998 a mock-up of the Long March 2F launch vehicle with Shenzhou spacecraft was rolled out for integration and facility tests.

On the 50th anniversary of the PRC's founding, China launched the Shenzhou 1 spacecraft on November 20, 1999 and recovering it after a flight of 21 hours. The country became the third country with a successful crewed space program by sending Yang Liwei into space aboard Shenzhou 5 on October 15, 2003 for more than 21 hours.

Anatoly Perminov, head of the Russian Federal Space Agency, revealed in September 2006 in RIA Novosti that Russia and China were working on lunar exploration as partners, and that the Russian-Chinese Space Sub-Commission's priority was to conclude a joint lunar exploration agreement by the end of that year. The first Chinese Lunar Exploration Program un-crewed lunar orbiter Chang'e 1 was successfully launched on October 24, 2007, making China the fifth nation to successfully orbit the Moon.

International co-operation

Shenzhou spacecraft and space station use a domestically made docking mechanism compatible with the Russian designed APAS docking adapter. The Sino-Russian-European psychosocial experiment Mars 500 provides the ground-based studies to complement orbital research in preparation for a planned manned mission to the planet Mars. Yinghuo-1, a Chinese Mars-exploration space probe, intended to be the first Chinese spacecraft to explore Mars, was launched from Baikonur Cosmodrome, Kazakhstan, on 8 November 2011, along with the Russian Fobos-Grunt sample return spacecraft, which was intended to visit Mars' moon Phobos. Shortly after launch, Fobos-Grunt was expected to perform two burns to depart Earth orbit bound for Mars. However, these burns did not take place, leaving the probe stranded in orbit. On 17 November 2011, Chinese state media reported that the probe had been declared lost by the CNSA.

Cooperation in the field of manned space flight between the CMSEO and the Italian Space Agency was examined in 2011, participation in the development of China manned space stations and cooperation with China in the fields such as astronauts flight, and scientific research was discussed. Potential areas and ways for future cooperation in the fields of development of manned space station, space medicine and space science have also been discussed during the meeting.

Precursor space stations

In Project 921, three space stations of varying sophistication lead up to the launch of the CSS, each testing and improving systems required for the CSS.

Tiangong 1 "target vehicle"

Originally, China planned to simply dock Shenzhou 8 and Shenzhou 9 together to form a simple space laboratory. However, it was decided to abandon that plan and launch a small space laboratory instead. In 2007, plans for a "space laboratory", Tiangong 1 were announced. Subsequent flights (Shenzhou 9 and Shenzhou 10) would dock with the laboratory. Tiangong 1 consisted of a propulsion module, and a pressurized module for experiments, with a docking mechanism at both ends. The docking port of the experiment section supported automated docking. Launched on September 29, 2011, it was intended for short stays of a crew of three. The second docking port, on the propulsion module, was kept screened from press photography inside and outside the module.

Tiangong 2 "space laboratory"

The Chinese Space Lab will be launched in 2013, for a crew of three and with twenty days of life support.

Tiangong 3 "space station"

The Chinese Space Lab is expected to be launched around 2015, with 40 days of life support for a crew of three. It shall be used to evaluate regenerative life-support technology, and verify orbital replenishment of propellant and air, similar in function to the Russian Elektron system used on Mir and the ISS.

Naming the CSS

The paramount leader of the People's Republic of China from 1978 to 1992 Deng Xiaoping changed the cultural fabric of the Chinese society and decided names used in the space program, previously all chosen from the revolutionary history of the PRC, would be replaced with mystical-religious ones. Thus, new Long March carrier rockets were renamed Divine arrow (神箭), spacecapsule Divine vessel (神舟), space shuttle Divine dragon (神龙), land-based high-power laser Divine light (神光) and supercomputer Divine might (神威).

These poetic names continue as the first, second, third, fourth and fifth Chinese Lunar probes are called Chang'e after the moon goddess. The name "Tiangong" means "heavenly palace".

Wang Wenbao, director of the CMSE, told a news conference in 2011 "Considering past achievements and the bright future, we feel the manned space programme should have a more vivid symbol, and that the future space station should carry a resounding and encouraging name. We now feel that the public should be involved in the names and symbols, as this major project will enhance national prestige and strengthen the national sense of cohesion and pride."

Structure

The CSS is a third generation modular space station. First generation space stations, such as early Salyut (fireworks) and Almaz (diamond) stations and skylab were monolithic single piece stations, were not designed for resupply. Salyut 6, 7 and Tiangong stations are designed for mid-mission resupply. Mir, the ISS, OPSEK and the CSS are modular space stations, assembled on-orbit from pieces launched separately. Modularized design methods can greatly improve reliability，reduce costs, shorten development cycle, and meet diversified task requirements.

Modules

The Core Cabin Module provides life support and living quarters for three crew members, and provides guidance, navigation, and orientation control for the station. The module also provides the station’s power, propulsion, and life support systems. The module consists of three sections, living quarters, service section and a docking hub.

The living quarters will contain a kitchen and toilet, fire control equipment, atmospheric processing and control equipment, computers, scientific apparatus, communications equipment to see and hear ground control in Beijing, and other equipment.

The first of two Laboratory Cabin Modules will provide additional navigation avionics, propulsion and orientation control as backup functions for the CCM. Both LCMs provide a pressurised environment for researchers to conduct science experiments in freefall or Zero-gravity which could not be conducted on Earth for more than a few minutes. Experiments can also be placed on the outside of the modules, for exposure to the space environment, cosmic rays, vacuum, and solar winds.

Like Mir and the Russian orbital segment of the ISS, the CSS modules will assemble themselves in orbit, in contrast to the US Orbital Segment of the ISS, which required spacewalking to interconnect cables, piping, and structural elements manually. The axial port of the LCMs will be fitted with rendezvous equipment and will first dock to the axial port of the CCM. A mechanical arm similar to the Russian Lyappa arm used on the Mir space station will then move the module to a radial port of the CCM.

Electrical system

Electrical power is provided by two steerable solar power arrays on each module, which use photovoltaic cells to convert sunlight into electricity. Energy is stored to power the station when it pass into the Earths shadow. Resupply ships will replenish fuel for the stations propulsion engines for station keeping, to counter the effects of atmospheric drag.

Fleet

The station will be resupplied by manned spacecraft and robot cargo ships.

Shenzhou

The Shenzhou is designed primarily to carry crew into orbit, it consists of three modules, a forward orbital module (轨道舱), used by crew as working and living space, a reentry module (返回舱) in the middle, which removes all unnecessary equipment making the simplest and thereby safest return to earth, and an aft service module (推进舱), which contains engines, propellants, guidance and orientation control, and cooling. Anything placed in the orbital or service modules does not require heat shielding, and this increases the space available in the spacecraft without increasing weight as much as it would if those modules were also able to withstand reentry. Thus both Soyuz and Shenzhou have more living area with less weight than the Apollo CSM. The mass of the ship is around 8,000 kg, it is 9.25 m long, and the maximum diameter of the modules is 2.80 m, with solar panels extended, it's 17.00 m across.

Until Shenzhou 8, the orbital module of the Shenzhou was equipped with its own propulsion, solar power, and control systems, allowing autonomous flight. It was possible for Shenzhou to leave an orbital module in orbit for redocking with a later spacecraft, something which the Soyuz cannot do since the only hatch between orbital and reentry modules is a part of reentry module, and orbital module is depressurized after separation. In the future it is possible that the orbital module(s) could also be left behind on station as additional station modules. Small modules for the ISS are launched by Soyuz spacecraft in this way. In unmanned test flights the orbital module of each Shenzhou was left functioning on orbit for several days after the reentry modules return, and the Shenzhou 5 orbital module continued to operate for six months after launch.

Robot cargo ship

Modified versions of Tiangong spacecraft will be used as robotic cargo spacecraft to resupply this station. The launch mass of the Tiangong-1-derived cargo spacecraft is expected to be around 13,000 kg with a payload of around 6,000 kg. Launch, rendezvous and docking shall be fully autonomous, with mission control and crew used in override or monitoring roles. This system becomes very reliable with standardisations that provide significant cost benefits in repetitive routine operations. An automated approach could allow assembly of modules orbiting other worlds prior to manned missions.

Safety

Orbital debris

The CSS will be operated in Low Earth Orbit, 340 to 450 kilometers above the Earth at an orbital inclination of 42 to 43 degrees, in the center of the Earths Thermosphere. At this altitude there is a variety of space debris, consisting of many different objects including entire spent rocket stages, dead satellites, explosion fragments—including materials from anti-satellite weapon tests, paint flakes, slag from solid rocket motors, coolant released by RORSAT nuclear powered satellites and some of the 750,000,000 small needles from the American military Project West Ford. These objects, in addition to natural micrometeoroids, are a significant threat. Large objects could destroy the station, but are less of a threat as their orbits can be predicted. Objects too small to be detected by optical and radar instruments, from approximately 1 cm down to microscopic size, number in the trillions. Despite their small size, some of these objects are still a threat because of their kinetic energy and direction in relation to the station. Spacesuits of spacewalking crew could puncture, causing exposure to vacuum.

Space debris objects are tracked remotely from the ground, and the station crew can be notified. This allows for a Debris Avoidance Manoeuvre (DAM) to be conducted, which uses thrusters on station to change orbital velocity and altitude, avoiding the debris. DAMs will take place if computational models show the debris will approach within a certain threat distance. Usually the orbit will be raised saving fuel, as the stations orbit must be boosted periodically to counter the effects of atmospheric drag. If a threat from orbital debris is identified too late for a DAM to be safely conducted, the station crew close all the hatches aboard the station and retreat into their Shenzhou spacecraft, so that they would be able to evacuate in the event it was damaged by the debris. Micrometeorite shielding is incorporated into the station to protect pressurised sections and critical systems. The type and thickness of these panels varies depending upon their predicted exposure to damage.

Radiation

Stations in low earth orbit are partially protected from the space environment by the Earth's magnetic field. From an average distance of about 70,000 km, depending on Solar activity, the magnetosphere begins to deflect solar wind around the Earth and space stations in orbit. However, solar flares are still a hazard to the crew, who may receive only a few minutes warning. The crew of the ISS took shelter as a precaution in 2005 in a more heavily shielded part of that station designed for this purpose during the initial 'proton storm' of an X-3 class solar flare, but without the limited protection of the Earth's magnetosphere, China's planned manned mission to Mars is especially at risk.

Subatomic charged particles, primarily protons from cosmic rays and solar wind, are normally absorbed by the earths atmosphere, when they interact in sufficient quantity their effect becomes visible to the naked eye in a phenomena called an Aurora. Without the protection of the Earth's atmosphere, which absorbs this radiation, station crews are exposed to about 1 millisievert each day, which is about the same as someone would get in a year on Earth, from natural sources. This results in a higher risk of crew members developing cancer. Radiation can penetrate living tissue and damage DNA, cause damage to the chromosomes of lymphocytes. These cells are central to the immune system and so any damage to them could contribute to the lowered immunity experienced by crew. Radiation has also been linked to a higher incidence of cataracts in astronauts. Protective shielding and protective drugs may lower the risks to an acceptable level.

The radiation levels experienced on ISS are about 5 times greater than those experienced by airline passengers and crew. The Earth's electromagnetic field provides almost the same level of protection against solar and other radiation in low Earth orbit as in the stratosphere. Airline passengers, however, experience this level of radiation for no more than 15 hours for the longest intercontinental flights. For example, on a 12 hour flight an airline passenger would experience 0.1 millisievert of radiation, or a rate of 0.2 millisieverts per day; only 1/5 the rate experienced by an astronaut in LEO.

End of orbit

The station has a service life of ten years. Chinese manned spacecraft use deorbital burns to slow their velocity, resulting in their re-entry to the earths atmosphere. Vehicles carrying a crew have a heat shield which prevents the vehicles destruction caused by friction with the Earths atmosphere. The CSS has no heat-shield, however small parts of space stations reach the surface of the Earth, so uninhabited areas are targeted by de-orbit maneuvers.

External links

 Chinese Space Agency website,

v t e Space stations and settlements
List of space stations List of commercial space stations
Current	International Space Station (ISS) Tiangong space station (TSS)
Past	Russia / Soviet Union Salyut Salyut 1 DOS-2 Salyut 2 Cosmos 557 Salyut 3 Salyut 4 Salyut 5 Salyut 6 Salyut 7 Mir United States OPS 0855 Skylab China Tiangong program Tiangong-1 Tiangong-2 Private Genesis I II
Canceled	Individual projects Aurora Station Bigelow Commercial Space Station Deep Space Habitat Excalibur Almaz Exploration Gateway Platform Galaxy Industrial Space Facility Manned Orbiting Laboratory Nautilus-X OPSEK Orbital Technologies Commercial Space Station Skylab II (FlexCraft) Skylab B Sundancer Tiangong-3 Incorporated into ISS Space Station Freedom USOS Columbus MTFF Columbus (ISS module) Mir-2 ROS
In development	Russia Russian Orbital Service Station Private Axiom Station Haven-1 Orbital Reef Starlab International Lunar Gateway
Proposed	Bharatiya Antariksha Station Japanese Space Station Module (Mitsui) Lunar Orbital Station Voyager Station
Concepts	Bernal sphere Bishop Ring McKendree cylinder O'Neill cylinder Rotating wheel Space settlement Stanford torus Wet workshop
Related	List of films featuring space stations Space stations and habitats in fiction Mission to Mir (1997 documentary) Space Station 3D (2002 documentary) Orphans of Apollo (2008 documentary) Space Tourists (2009 documentary) A Beautiful Planet (2016 documentary)
Notes: † Never inhabited due to launch or on-orbit failure, ‡ Part of the Almaz military program, ° Never inhabited, lacks docking mechanism.

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• Geography of the People's Republic of China
• Chinese space program
• Human spaceflight
• Manned spacecraft
• Space stations