Life blooms, flames dance...space experiments are so interesting!

Produced by: Science Popularization China

Author: China Science Expo

Producer: China Science Expo

In the vast space about 400 kilometers away from the earth, China's Tiangong space station is whizzing by at a speed of 7.9 kilometers per second, becoming a new frontier for human exploration of the mysteries of the universe. In this vast expanse of space, scientists are conducting a series of fascinating life science experiments and space combustion science experiments, trying to uncover the mystery of life and fire in the space environment.

Life blooms in space

In the Wentian Experimental Module of the Chinese Space Station, a 120-day rice cultivation experiment was carried out throughout its life cycle in space. This was the first time in the world that rice seeds were produced in space. Scientists, such as Zheng Huiqiong, a researcher at the Center for Excellence in Molecular Plant Sciences of the Chinese Academy of Sciences, took an important step towards growing food crops in space through this experiment.

Zheng Huiqiong, a researcher at the Center for Excellence in Molecular Plant Sciences of the Chinese Academy of Sciences, said that allowing rice to produce seeds in space is only the first step. In the future, they plan to use these rice seeds to complete 2-3 generations of plant experiments from seed to seed in space, and conduct in-depth research on the adaptability of plants to long-term space environments and the stability of genetic mechanisms.

This research is not only of scientific value, but also of far-reaching significance. Cang Huaixing, a researcher at the Space Application Engineering and Technology Center of the Chinese Academy of Sciences, pointed out that once the laws related to plants in space are thoroughly studied, humans will be able to cultivate food crops suitable for growing in space, which will play a vital role in future space exploration, whether it is the construction of a lunar base or the Mars immigration plan.

The Life Ecology Experiment Cabinet, a facility that is figuratively called a "space hotel", provides scientists with a valuable platform for studying the growth, development and aging of biological individuals in a microgravity and radiation environment. In the experiment cabinet, different research objects have been given personalized experimental device designs, from plant seeds and seedlings to micro-animals such as fruit flies and nematodes, and even small rodents such as mice, all can find a suitable research environment here.

Schematic diagram of life ecology experiment cabinet

(Photo source: Science Institute)

At the same time, the biotechnology experiment cabinet conducts research from a microscopic perspective, using samples such as biological tissues, cells and biochemical molecules as objects to explore the impact of the space environment on life. For example, through lung cell culture experiments, scientists can examine the impact of space radiation on lung cell growth, thereby revealing the potential risks of the space environment to human health.

Firebenders in Space

On the other side of space, combustion science experiments are in full swing. Fire, a mysterious substance that has accompanied human development since primitive people knew and used it tens of thousands of years ago, exhibits a combustion phenomenon that is completely different from that on Earth in the microgravity environment of space.

The core of the combustion science experiment cabinet is a combustion chamber. In addition to the torch formed in the center of the combustion chamber, there are various measuring instruments inside and outside the combustion chamber, which can detect whether the ignition is successful and the subtle changes in the flame. It can also detect the spatial distribution of the temperature and concentration of the flame up to more than 1,500 degrees, and study the physical and chemical process of combustion hidden by gravity.

Liu Yousheng, an associate professor at Tsinghua University and the responsible scientist for the combustion science experiment, pointed out that there are two main purposes of the space combustion experiment: one is to study the deep-seated mechanism of fire prevention problems in the space station, and the other is to provide theoretical support for energy systems and power system devices related to combustion on the ground and in the aerospace field.

With the help of the combustion science experiment cabinet, scientists can study the combustion process in a microgravity environment, eliminate the buoyancy convection effect, inhibit the sedimentation of particles or droplets, and thus observe the physical and chemical process of combustion hidden by gravity. This research is of great significance for the development of reaction kinetics theory and the optimization of ground combustion power systems.

Image of methane combustion in the combustion science experiment cabinet on the space station (left) and image of methane combustion under the same working conditions on the ground (right) (Image source: Institute of Engineering Thermophysics, Chinese Academy of Sciences, Tsinghua University Combustion Energy Center)

On February 16, 2023, the experimental system in the combustion science cabinet in the Mengtian module successfully carried out the first on-orbit ignition test, using methane as fuel, showing a flame form that is completely different from that on the ground. After the astronauts closed the door of the combustion chamber, all instructions were issued by the ground operation and control center, and the corresponding team issued instructions. The ignition inside can be said to be fully automatic. Through these instructions, the combustion chamber is evacuated to vacuum, and the desired ambient gas is input. After reaching a certain ratio, we will then add fuel gas.

When the influence of gravity is lost, the small fireball presents a completely different state from that on the ground. Compared with the same experimental results on the ground, the external diffusion flame is shorter and rounder, and the flame layers are more clearly visible. This experiment not only marks an important breakthrough in China's space combustion experiment, but also provides a new perspective for human exploration of combustion, an ancient and ever-new natural process.

Conclusion

From the blooming of life in space to the dancing of flames in space, China's Tiangong Space Station is becoming an important platform for humans to explore the mysteries of the universe. With the continuous efforts of scientists, I believe that in the near future, we will be able to uncover more mysteries about life and flames in the space environment and lay a solid foundation for human space exploration.