Before you know it, the Shenzhou 17 mission is coming to an end. On October 26, 2023, the Shenzhou 17 spacecraft was launched, and it has been in orbit for more than 6 months now.
According to the China Manned Space Engineering Office, at 8:43 Beijing time on April 30, 2024, the Shenzhou-17 manned spacecraft and the space station assembly were successfully separated. Like previous missions, the Shenzhou-17 spacecraft will continue to use the technology of rapid return in the process of returning home.
According to the plan, the Shenzhou-17 spacecraft will adopt a five-lap rapid return plan, and land on the ground after braking deorbiting, free coasting, re-entry, parachute landing and other processes, and the entire return and landing project will take about 50 minutes.
There are many benefits to a fast return, and the flight time is drastically reduced. Because astronauts need to wear in-cabin spacesuits and sit in the spacecraft return capsule when they return to Earth from the space station, and the space in the spacecraft return capsule is very limited, if they are in the narrow re-entry capsule for a long time, the astronauts will be very uncomfortable, after all, they can't move. Now, with the technology of rapid return, the astronauts have a very short time in the re-entry capsule, and after being evacuated from the space station complex, it will not take long to return to the surface.
The Dongfeng landing site is ready
On the afternoon of April 26, the Dongfeng landing site conducted the last system-wide comprehensive drill of the Shenzhou-17 search and rescue recovery mission. In this comprehensive exercise, all aspects of equipment and work processes were comprehensively simulated, including air search and rescue, ground disposal, surveying, and communications. It can be said that everything is ready, just waiting for the triumphant return of Shenzhou 17.
On April 28, the Shenzhou-17 and Shenzhou-18 astronaut crews held a handover ceremony in orbit, and the two crews handed over the keys to China's space station. The search and rescue detachments and equipment at the Dongfeng landing site are in good condition, and the personnel are already ready, and they are now waiting for the Shenzhou-17 astronaut crew to return home.
Since the beginning of the Shenzhou-12 spacecraft, we have used the Dongfeng landing field to welcome the triumphant return of the Shenzhou spacecraft, and we have very rich experience in this area, which has also become a normal thing. Although each search and rescue mission does not seem to change much, the process of welcoming the spacecraft back is not as simple as repeating the previous operation.
Because the spacecraft may encounter unexpected or unexpected situations on the way back to Earth, it is necessary to take countermeasures according to the actual situation. For example, when the spacecraft returns, it may deviate from the pre-selected landing site due to the influence of the wind, and there may be other large wild animals near the actual landing site when landing. Therefore, in order to effectively deal with emergencies during the return process, the landing site needs to make a series of preparations in advance before each spacecraft returns, and various emergency plans need to be made to ensure that nothing goes wrong.
For the first time, China will raise fish in space
Now that the Shenzhou-17 spacecraft has successfully returned home, the Chinese space station is about to be handed over to the Shenzhou-18 astronaut crew. The Shenzhou-18 spacecraft was successfully launched on the evening of April 25, and in this mission, in addition to astronauts, there is also an internal capacity of 1.25 liters of "aquarium", and the astronauts will carry out space fish farming work for the first time in China's space station.
According to the plan, this space fish farming research will take zebrafish and goldfish algae as research objects, establish a stable operation of space self-circulating aquatic ecosystem in orbit, and achieve a breakthrough in the continent's cultivation of vertebrates in space.
There are many species of fish, why choose to transport zebrafish to outer space to carry out related research? Although zebrafish may seem inconspicuous, it is favored by scientists in the field of space science research and applications. As early as 1976, zebrafish went on a "tour" to space, when scientists from the former Soviet Union sent zebrafish to the Salyut 5 space station.
As a fish that has traveled to space, zebrafish has many advantages, such as zebrafish farming is very simple, the development is also very rapid, the sexual maturity cycle is relatively short, the spawning is relatively large, there are many transgenic and mutant strains, in addition, zebrafish and our human genetic similarity reaches 87%. This time, the Shenzhou-18 spacecraft has sent 4 zebrafish and 4 grams of goldfish algae to the Chinese space station, and the mainland has officially opened the first space fish farming.
Raising fish on the space station is far more complicated than you think, because the outer space environment is weightless. The goldfish algae photosynthesizes through a lighting system in the experimental setup to produce oxygen, which can be used to breathe the zebrafish.
The carbon dioxide produced by the respiration of these zebrafish can be used for photosynthesis of these goldfish algae, and the excrement can also be used as a nutrient for these goldfish algae. From here, it can be seen that this space fish farming device is actually a binary ecosystem. Due to the weightlessness of the outer space environment, it is necessary to conduct further in-depth research to know what will affect these zebrafish and goldfish algae in the experimental device.
Source: WeChat public account "Bright Science"
Editor: Star City
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