Visitors file into a dummy module of Tiangong-2 space lab displayed at the China Science and Technology Museum in Beijing on September 17 (XINHUA) 

When the Chinese looked up at the sky to gaze at the Moon during the Mid-Autumn Festival on September 15, they had one more thing to celebrate--the launch of Tiangong-2, literally meaning "heavenly palace"--China's second space lab.

The launch marks one step further toward realizing the goal of setting up a permanent space station. Since ancient times, the Chinese have cherished the thought of landing on the Moon. The myth about Chang'e, the woman who drank the elixir of life became immortal and flew to the Moon, is an embodiment of that aspiration.

The space lab is designed to operate for at least two years. In October, two astronauts will be sent there on the Shenzhou-11 spacecraft to stay for 30 days and conduct experiments in biology, physics and medicine.

China's manned space program started in 1992. The first goal, sending an astronaut into space, was achieved in 2003. The second, to send manned spaceships with astronauts so that they can stay in space labs temporarily and conduct experiments, is close to fruition. The third is to build a permanent space station by 2020.

China's first space lab, Tiangong-1, was put into orbit in September 2011 and three astronauts have lived there for 15 days. Tiangong-2, 10.4 meters long and with a diameter of nearly 3.35 meters, resembles its predecessor, but its interior living quarters and life support systems are vastly improved so that astronauts can stay up longer.

Major tasks 

The key tasks of Tiangong-2 are to accommodate astronauts for a medium length of time, and serve as a platform for testing in-orbit refueling and equipment repairs, said Wu Ping, Deputy Director of the China Manned Space Engineering Office, at a press conference on September 14.

Prior to the two astronauts' arrival in October, a number of in-orbit tests will be conducted on the space lab, including tests on its power supply and information transmission to support the docking of the transport spacecraft and the astronauts' space sojourn, Wu said. Then the space lab will operate independently.

Before the rendezvous with Shenzhou-11, the space lab will launch its own mini-satellite, which will film the lab and be used in experiments.

Tiangong-2 carries sophisticated devices for conducting 14 experiments on board. The devices include a cold atomic clock, the most accurate clock in the world, which will slow down by just one second in 30 million years. The name comes from the use of atoms of chemical elements such as rubidium, which are cooled down with a laser.

The cold atomic clock can be used to calibrate other atomic clocks on satellites and make the satellite navigation systems more precise. Scientists can also compare the time recorded by the clock in space and on Earth to identify the effect of gravity on time, and study gravitational redshift. Redshift is the phenomenon when light or other electromagnetic radiation from an object is increased in wavelength.

The space lab also carries POLAR, a polarimeter jointly developed by Swiss, Polish and Chinese institutions to study gamma ray bursts (GRBs). Accurate observation of GRBs and solar flares will help to understand these phenomena, as well as the structure, origin and evolution of the universe, Wu said.

GRBs, which are extremely energetic electromagnetic events, have been observed in distant galaxies. In a few seconds, a typical burst can emit as much energy as the Sun will in its estimated 10-billion-year lifetime.

In a special greenhouse on Tiangong-2, the astronauts will also try to grow rice and rock cress. The greenhouse has two regular cameras and a third special fluorescent one to study the plants. This is the first time that a plant's full lifecycle will be tested in space, said Zheng Huiqiong, a researcher with the Institute of Plant Physiology and Ecology of Shanghai Institutes for Biological Sciences. She added that the seeds of the plants grown there will be brought back to the earth to be studied by scientists.

The space lab also has a new generation of remote sensing instruments and earth science research instruments which will be used for better researching global climate change and monitoring atmospheric pollution.

 

A computer-generated image of Tiangong-2 (XINHUA)

Social benefits 

Although the space program will explore the sky, it is also closely related to people's life on the Earth. It will promote scientific and technological progress, social and economic development, and improve people's living standards, Wu said.

A manned space program involves multiple scientific and engineering fields, from mechanics, astronomy and earth and space sciences to remote sensing, new energy and materials, as well as optoelectronics. Since the manned space program began, breakthroughs have been made in a series of core technologies and nearly 1,000 invention patents have been granted.

In the past two decades, more than 2,000 technological outcomes of the manned space program have been widely applied in various sectors. A research agency estimates the input-output ratio of such projects to be 1:10 to 1:12, Wu said. Some items of daily use such as juice powder and dehydrated vegetables have also originated from the manned space program, she added.

In recent years, China has been committed to promoting the use of aerospace technology in the civilian sector, for instance, to prevent coal mine accidents or treat elderly patients with low bone density.

The China Manned Space Engineering Office has signed strategic cooperative agreements with the governments of Yunnan Province in southwest China and Ningxia Hui Autonomous Region in the northwest to develop specialty industries with outcomes from the manned space program. Wu believes the development of manned space technology will make greater contributions to society and bring more benefits to people.

Copyedited by Sudeshna Sarkar

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