Author: Dr. Lin LIU Dr. Lin LIU is a distinguished professor at the Astronomy and Space Science Institute, Nanjing University. He is regarded as the main founder of the research in celestial dynamics and spacecraft orbit determination in China. He has been involved in Chinese Space projects including the Shenzhou Spacecraft project and the Moon Exploration project. He formerly held the director positions at the Chinese Astronomy Society and the Chinese Aerospace Society Translator: Dr. Shengpan Zhang Dr. Shengpan Zhang is a retired scientist. She formerly worked as an associate professor at Nanjing University and as a research scientist at York University, both in astronomy. She received NASA's Group Achievement Award for her contribution to the UARS space project. Her research focuses on the stability of the solar system and orbit theory, and the upper atmospheric physics.