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中国空间站将定位于400-450km轨道上，倾角42-43度，寿命10年
China Out Front With Human Lunar Planning
Oct 16, 2009
Frank Morring, Jr. and Bradley Perrett/Daejeon, South Korea
Previously circumspect, Chinese space officials are out front now about their interest in sending their astronauts to the Moon on their own, even as they worked the halls of the International Astronautical Congress (IAC) here to establish closer outside links for human-spaceflight cooperation.
Dong Nengli of China’s Manned Space Engineering Program says his organization—which developed the Shenzhou human spacecraft and is planning an unpiloted orbital rendezvous and docking experiment in 2011—is already looking beyond the planned deployment of a 60-ton Chinese station in 2020.
“During the course of the third step of the China manned-spaceflight program, we will conduct a manned lunar mission conception study, validate the key technologies and finally pave the way for manned lunar exploration,” Dong told a press conference on his country’s space program on Oct. 15.
Chinese officials stress that there has been no government approval for a manned lunar landing, and they say China would “welcome” a chance to join the larger international exploration effort that has coalesced around the International Space Station.
“If the Americans and the International Space Station [partners] put forward this kind of cooperation suggestion, we would definitely really welcome these suggestions,” says Wang Jongqui, deputy chief designer of the Manned Space Engineering Program. “We would seriously take that into consideration.”
To that end, Wang and his delegation—which included Chinese spacewalker Zhai Zhigang—met with representatives of the French and German national delegations to the congress here. Their presence at the IAC marks a change in the public face of China’s space program, which in the past has sent representatives of the civilian China National Space Agency (CNSA) to the annual event.
This year, CNSA Administrator Sun Laiyan, a regular at past IAC heads-of-agency plenary sessions, withdrew from the congress after the programs had been printed. Officials of two different Western space agencies say there have been indications the CNSA is on the outs in Beijing, while the head of the Manned Space Engineering Office—Wang Wenbao—told Aviation Week and a delegation from the Space Foundation on Sept. 22 that his organization is handling human spaceflight for the central government (AW&ST Sept. 28, p. 24).
The management-level Manned Space Engineering Office and the Manned Space Engineering Program, which handles the technical side of the human-spaceflight effort, draw their funding from the Chinese military. All of the nation’s astronauts are military pilots; but like their counterparts from the U.S. and Russia, they do not wear their uniforms at international gatherings such as the IAC, and program officials downplay the military link when questioned about it.
Dong and other officials here offered no details about the human lunar concept study, which has been mentioned in Chinese-language technical publications but not announced at an international forum before. Instead, they elaborated on plans to continue gaining spaceflight experience by building toward the 60-ton, three-person space station and to follow up the second Chang’e lunar orbiter—which is set for launch next year—with a robotic lander, rover and eventually a sample-return mission.
The first miniature space station, Tiangong 1, is under construction and still scheduled to go into orbit in 2011 to serve as a docking target for the Shenzhou 8 spacecraft, which will be unmanned. If that goes well, China will move into a series of manned rendezvous and docking tests with Tiangong 1. Wang says there will be two or three Tiangongs, which officials previously said will weigh 8.5 tons. A Tiangong will be set up as a space laboratory in 2013. Astronauts will use it to practice medium-term stays in orbit and to perform scientific experiments. “By operating the space laboratory, China will accumulate experience in building, managing and operating the future space station,” says Dong.
Since China’s upcoming heavy-lift launcher, the Long March 5, will not go into service until 2014, the laboratory’s mass will be limited by the throwweight of the current Long March series, the most powerful of which can lift 13 tons to low orbit.
A robotic cargo craft also is planned to resupply the larger space station, and Wang says it will be structurally related to the Tiangong series.
The docking port China is developing for the Shenzhou 8 mission is similar in diameter to, but not compatible with, the Russian-designed system used on the ISS, Wang says. However, China would be interested in hearing any suggestions that could lead to an international docking-interface standard, he notes.
A concept plan has been finished for the 60-ton space station, which would follow around 2020 (the previous target was “by 2020”). It will be assembled in orbit from three modules, matched to the capability of the Long March 5 and launch from the low-latitude site under construction on Hainan Island. China has said at least one of the station modules will weigh 20 tons; the others are likely to be close to that. Designed to sustain a crew of three for long-duration missions, the station would orbit at an altitude of 400-450 km. (248-280 mi.) and an inclination of 42-43 deg, with a planned service life of 10 years.
The ISS, with a mass of about 300 tons, generally orbits at an altitude less than 400 km. and at an inclination of 51.6 deg., with accommodation for six. It began service in 2000 and—if the recommendations of the Augustine panel reviewing the future of U.S. human spaceflight are followed—would be shut down in 2020, just as the Chinese station becomes operational.
While China builds up experience with human spaceflight in low orbit, it will continue sending robotic probes to the Moon before bringing the two strands together with a possible manned landing. The next lunar mission will be Chang’e 2, due to be launched next October, following the successful Chang’e 1 mission of 2008-09. The Chang’e 2 probe was previously a backup for its predecessor and will orbit the Moon at an altitude of 100 km. Its equipment will include a camera with a resolution of better than 10 meters (33 ft.).
Chang’e 3 will land on the Moon, executing the second phase of the robotic lunar exploration plan. The 3,750-kg. (8,250-lb.) spacecraft is due to be launched in 2012 directly to the Moon without first orbiting the Earth, inserted into a 100 X 100-km. orbit that will be adjusted to 100 X 15 km. When the vehicle reaches the 15-km. perigee, its engine will begin reducing its velocity from 1.7 km./sec. to about zero, turning it to a vertical attitude before the craft reaches an altitude of 2 km. The lander will hover at 100 meters, moving horizontally to avoid any hazards, and then slowly descend to 4 meters, at which point its engine will shut down for a free fall to the surface.
The lander will carry a rover. The scientific objectives include investigating the geological structure of the Moon, its material composition, internal structure and usable materials, and “to build up an observatory” based on the Moon. A later mission “before 2017” will be aimed at bringing lunar samples back to Earth.
China is also looking at sending a probe to Mars, using the experience and infrastructure developed with the Chang’e missions. |
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