China's Shenzhou 18 spacecraft brought back ‘space specialities’ involving 28 scientific experiments.

In the early morning of 4 November 2024, the seventh batch of space science experiment samples from the Chinese space station returned smoothly with Shenzhou XVIII. A total of 55 scientific experiment samples were sent down, involving 28 scientific experiment projects in the fields of space life science, space material science and microgravity combustion science, with a total weight of about 34.6 kg.

On the morning of the 4th, samples of life-type scientific experiments were transferred to the Centre for Space Application Engineering and Technology of the Chinese Academy of Sciences (CASA) in Beijing in the first instance. As the overall unit of the space application system of the manned space engineering project, the Space Application Engineering and Technology Centre of the Chinese Academy of Sciences checked and confirmed the basic status of the returned life experiment samples before delivering them to scientists for follow-up research.

The life-like samples that descended with Shenzhou 18 include zebrafish culture medium, amino acids, oligopeptides, methanogenic archaea, radiation-resistant microorganisms, lithobiotic microorganisms, and lichens, totalling 24 species.

Follow-up researchers will focus on a number of studies, such as macro-genome sequencing, phenotypic genetic analysis, proteomic and transcriptomic analyses:

Focus on the study of the material cycling mechanism of aquatic ecosystems in the space environment, to provide theoretical support for the construction of complex ecosystems that operate stably in space for a long period of time;
Focusing on the impact of microgravity effect on the chemical origin of codons and what kind of space environment there may be a complex molecular basis for life;
To study the adaptability of anaerobic archaea to extraterrestrial environments, providing a key a priori research basis for the exploration of the extraterrestrial habitability of life;
To assess the survival limits and tolerance of microorganisms in extreme environments, to explore the ability of microorganisms in extreme environments to expand into outer space, to study the possibility of interstellar propagation of life on Earth, and to validate the hypothesis of rocky biogenicity.

It is learnt that the material and combustion samples will be transported back to Beijing with the return capsule of the spacecraft. The material samples on the way down include 30 kinds of high-temperature refractory niobium alloys, FeSi-based soft magnetic alloys, biologically active glasses, composite lubricating materials, optical fibres and optical films.

After the return, the researchers will carry out testing and analysis of tissue morphology, chemical composition and its distribution differences, study the effect of gravity on the growth of materials, compositional segregation, solidification defects and properties of the law, study the service behaviour and service performance of the materials in the special environment of the space, which can provide technological support in the next generation of aero-engine turbine blades, fibre-optic lasers used in space, precision medical repair and other areas of materials manufacturing and application. It will promote the space application of long-life space lubrication materials, neutron shielding materials for precision electronic equipment, porous metal materials for acoustic and thermal insulation, and high-performance metal soft magnetic materials.

The returned combustion samples are nanoparticle materials synthesised based on methane combustion. Upon return, the scientists will analyse the particle size, morphology, lattice structure, etc., and study the influence of gravity on the evaporation of precursor droplets, aggregation and growth of nanoparticles, and crystallisation during the gas-phase combustion synthesis process, in an effort to lay the foundation for the technological development of the gas-phase synthesis of key particulate materials in extraterrestrial environments.