Quantum technology establishes a foundation for secure communication via quantum key distribution （QKD）. In the last two decades, the rapid development of QKD makes a global quantum communication network feasible. I...Quantum technology establishes a foundation for secure communication via quantum key distribution （QKD）. In the last two decades, the rapid development of QKD makes a global quantum communication network feasible. In order to construct this network, it is economical to consider small-sized and low-cost QKD payloads, which can be assembled on satellites with different sizes, such as space stations. Here we report an experimental demonstration of space-to-ground QKD using a small-sized payload, from Tiangong-2 space lab to Nanshan ground station. The 57.9-kg payload integrates a tracking system, a QKD transmitter along with modules for synchronization, and a laser communication transmitter. In the space lab, a 50MHz vacuum＋weak decoy-state optical source is sent through a reflective telescope with an aperture of 200mm. On the ground station, a telescope with an aperture of 1200mm collects the signal photons. A stable and high-transmittance communication channel is set up with a high-precision bidirectional tracking system, a polarization compensation module, and a synchronization system. When the quantum link is successfully established, we obtain a key rate over 100bps with a communication distance up to 719km. Together with our recent development of QKD in daylight, the present demonstration paves the way towards a practical satellite-constellation-based global quantum secure network with small-sized QKD payloads.展开更多
In the past two years,China’s space life science has made great progress.Space biomedical and life science programs have carried out ground-based research for the first batch of projects,and are preparing to carry ou...In the past two years,China’s space life science has made great progress.Space biomedical and life science programs have carried out ground-based research for the first batch of projects,and are preparing to carry out space-based experiments along with the construction of China’s space station.And space life science payload of the space station completed the development of positive samples.Thus,with the development of lunar exploration and Mars exploration projects,astrobiology research has also made a lot of basic achievements.On the basis of summarizing the development of space life science in China,this paper mainly introduces the important progress of payload technology and life science research.展开更多
With the human space exploration activities,space life science is an emerging interdisciplinary and it covers a wide range of research.Based on our country's manned space station and recoverable satellite science ...With the human space exploration activities,space life science is an emerging interdisciplinary and it covers a wide range of research.Based on our country's manned space station and recoverable satellite science experimental platform,the development of space life science research is very important to acquire new knowledge or new innovation in technology,to give further services to the human space exploration activities,to improve the national economic and social development.Based on present situation,both theoretical and applied researches were continuously performed in2015.Here,we review and summarize the researches on space life sciences which were contributed by Chinese scientists.展开更多
In 1957, the launch of the first artificial satellite ushered in a new era for modern space science. The past 50 years' developments in China's space science have witnessed many major missions, and substantial...In 1957, the launch of the first artificial satellite ushered in a new era for modern space science. The past 50 years' developments in China's space science have witnessed many major missions, and substantial progress has been achieved in space science study, exploration technology as well as experiment technology. Strategic Priority Program on Space Science was officially started in 2011. Through both self-developed space science missions and those with international cooperation,it is expected that the innovative breakthroughs will be realized, leapfrog development of related high-tech will be achieved to establish the important strategic status of space science in national development. To sum up, the implementation of the Strategic Priority Program on Space Science will definitely promote the rapid development of China's space science endeavor, making contributions to China's development and the progress of human civilization.展开更多
With the human space exploration activities, space life science is an emerging interdiscipline,which covers a wide range of researches. Based on our country's manned space station and recoverable satellite science...With the human space exploration activities, space life science is an emerging interdiscipline,which covers a wide range of researches. Based on our country's manned space station and recoverable satellite science experimental platform, the development of space life science research is very important to acquire new knowledge or new technological innovation, to give further services to the human space exploration activities,to improve the national economic and social development. Both ground-based and flight applied studies were continuously performed in the previous 2 years. Here, we review and summarize the researches on space life sciences contributed by Chinese scientists.展开更多
基金Supported by China Manned Space Program,Technology and Engineering Center for Space Utilization Chinese Academy of Sciences,Chinese Academy of Sciencesthe National Natural Science Foundation of China
文摘Quantum technology establishes a foundation for secure communication via quantum key distribution （QKD）. In the last two decades, the rapid development of QKD makes a global quantum communication network feasible. In order to construct this network, it is economical to consider small-sized and low-cost QKD payloads, which can be assembled on satellites with different sizes, such as space stations. Here we report an experimental demonstration of space-to-ground QKD using a small-sized payload, from Tiangong-2 space lab to Nanshan ground station. The 57.9-kg payload integrates a tracking system, a QKD transmitter along with modules for synchronization, and a laser communication transmitter. In the space lab, a 50MHz vacuum＋weak decoy-state optical source is sent through a reflective telescope with an aperture of 200mm. On the ground station, a telescope with an aperture of 1200mm collects the signal photons. A stable and high-transmittance communication channel is set up with a high-precision bidirectional tracking system, a polarization compensation module, and a synchronization system. When the quantum link is successfully established, we obtain a key rate over 100bps with a communication distance up to 719km. Together with our recent development of QKD in daylight, the present demonstration paves the way towards a practical satellite-constellation-based global quantum secure network with small-sized QKD payloads.
基金Supported by Space Medical Experiment Project of China Manned Space Program(HYZHXM02003)。
文摘In the past two years,China’s space life science has made great progress.Space biomedical and life science programs have carried out ground-based research for the first batch of projects,and are preparing to carry out space-based experiments along with the construction of China’s space station.And space life science payload of the space station completed the development of positive samples.Thus,with the development of lunar exploration and Mars exploration projects,astrobiology research has also made a lot of basic achievements.On the basis of summarizing the development of space life science in China,this paper mainly introduces the important progress of payload technology and life science research.
文摘With the human space exploration activities,space life science is an emerging interdisciplinary and it covers a wide range of research.Based on our country's manned space station and recoverable satellite science experimental platform,the development of space life science research is very important to acquire new knowledge or new innovation in technology,to give further services to the human space exploration activities,to improve the national economic and social development.Based on present situation,both theoretical and applied researches were continuously performed in2015.Here,we review and summarize the researches on space life sciences which were contributed by Chinese scientists.
文摘In 1957, the launch of the first artificial satellite ushered in a new era for modern space science. The past 50 years' developments in China's space science have witnessed many major missions, and substantial progress has been achieved in space science study, exploration technology as well as experiment technology. Strategic Priority Program on Space Science was officially started in 2011. Through both self-developed space science missions and those with international cooperation,it is expected that the innovative breakthroughs will be realized, leapfrog development of related high-tech will be achieved to establish the important strategic status of space science in national development. To sum up, the implementation of the Strategic Priority Program on Space Science will definitely promote the rapid development of China's space science endeavor, making contributions to China's development and the progress of human civilization.
文摘With the human space exploration activities, space life science is an emerging interdiscipline,which covers a wide range of researches. Based on our country's manned space station and recoverable satellite science experimental platform, the development of space life science research is very important to acquire new knowledge or new technological innovation, to give further services to the human space exploration activities,to improve the national economic and social development. Both ground-based and flight applied studies were continuously performed in the previous 2 years. Here, we review and summarize the researches on space life sciences contributed by Chinese scientists.
