Recent Progress in Space Science and Applications on Chinese Space Station in 2022–2024

Chinese Space Station(CSS)has been fully deployed by the end of 2022,and the facility has entered into the application and development phase.It has conducted scientific research projects in various fields,such as space life science and biotechnology,space materials science,microgravity fundamental physics,fluid physics,combustion science,space new technologies,and applications.In this review,we introduce the progress of CSS development and provide an overview of the research conducted in Chinese Space Station and the recent scientific findings in several typical research fields.Such compelling findings mainly concern the rapid solidification of ultra-high temperature alloy melts,dynamics of fluid transport in space,gravity scaling law of boiling heat transfer,vibration fluidization phenomenon of particulate matter,cold atom interferometer technology under high microgravity and related equivalence principle testing,the full life cycle of rice under microgravity and so forth.Furthermore,the planned scientific research and corresponding prospects of Chinese space station in the next few years are presented.

The first comprehensive Milky Way stellar mock catalogue for the Chinese Space Station Telescope Survey Camera

The Chinese Space Station Telescope(CSST)is a cutting-edge two-meter astronomical space telescope currently under construction.Its primary Survey Camera(SC)is designed to conduct large-area imaging sky surveys using a sophisticated seven-band photometric system.The resulting data will provide unprecedented data for studying the structure and stellar populations of the Milky Way.To support the CSST development and scientific projects related to its survey data,we generate the first comprehensive Milky Way stellar mock catalogue for the CSST SC photometric system using the TRILEGAL stellar population synthesis tool.The catalogue includes approximately 12.6 billion stars,covering a wide range of stellar parameters,photometry,astrometry,and kinematics,with magnitude reaching down to g=27.5 mag in the AB magnitude system.The catalogue represents our benchmark understanding of the stellar populations in the Milky Way,enabling a direct comparison with the future CSST survey data.Particularly,it sheds light on faint stars hidden from current sky surveys.Our crowding limit analysis based on this catalogue provides compelling evidence for the extension of the CSST Optical Survey(OS)to cover low Galactic latitude regions.The strategic extension of the CSST-OS coverage,combined with this comprehensive mock catalogue,will enable transformative science with the CSST.

Progress of Space Medicine Research in China

With the approaching of the Chinese Space Station(CSS)era,the focus of space medicine applications and related research has shifted to addressing the astronauts’health support in long-duration spaceflights,including nutrition,countermeasure against the physiological effects of weightlessness,medical monitoring and support,psychology status,etc.,and accordingly the human experiments to simulate long-duration weightlessness have been carried out.Increasingly,basic research has been put forward in the key areas,such as space bone loss,cardiovascular dysfunction and the molecular mechanisms underlying radiobiological effects.Moreover,specific novel research fields,such as hypometabolism technology,were explored.The research projects in the field of space medicine experiment,as an important aspect of the Chinese Space Station’s application,have been officially approved and launched.

Improved position estimates for the Chinese Deep Space Station Kashi derived by geodetic very long baseline interferometry

A dedicated 24 h S/X dual-band geodetic very long baseline interferometry(VLBI) experiment was conducted in January 2015 with the goal of improving the position estimates for the Chinese Deep Space Station Kashi. Previously, the position estimates had been only accurate to ~20 cm, which is insufficient for future Chinese deep space explorations. The experiment design and data reduction are described with special emphasis on the limited frequency ranges of Kashi for bandwidth synthesis. A narrowed multi-band delay search window based on post-fit residuals was utilized to resolve the sub-ambiguities due to the drop of a frequency channel in fringe fit, which saved ~22% of the observations from the affected baseline. Final position estimates of Kashi were obtained from the global solution by using more than 5300 international VLBI sessions from August 1979 to September 2015, and estimates were found to be accurate to about 10, 25, and 20 mm in the X, Y, and Z components. Various statistical tests were run, and the estimates and precisions are believed to be reliable.