This was originally a physics winter vacation assignment, but it was allowed to be presented because it was too far behind in the class.
At the request of the physics teacher, the author searched the internet for some information, watched documentaries on astronaut training, and visited the science museum to learn about the steps of rocket launch. During the process of collecting information, some previously unnoticed issues were discovered (such as the assembly method of rockets, the risk of psychological disorders in astronauts, etc.). Finally, with the guidance of the physics teacher on relevant issues, this article was completed.
China's manned space flight started relatively late and faces many difficulties and challenges. At this moment, it is particularly necessary to summarize the solutions to previous problems and provide suggestions for future difficulties. The author attempts to discuss this topic from the perspective of a high school student.
Astronaut-related#
During the rocket launch, astronauts need to be prepared for the intense vibration, loud noise, and excessive weight of the rocket cabin. In a microgravity environment, the astronauts' diet and excretion are affected. In this environment, calcium in the astronauts' bones will be lost at an accelerated rate, increasing the risk of osteoporosis. In space, the confined space and long periods of solitude can make astronauts more prone to psychological disorders. Cosmic radiation can bombard astronauts' chromosomes, causing incalculable effects. In addition, the extremely low atmospheric pressure in space poses strict requirements for spacesuits. (Main reference: https://www.bilibili.com/video/BV1Cd4y1c7GR/)
Astronauts need to undergo several years, or even decades, of rigorous training before carrying out missions to ensure that they can calmly and correctly handle emergencies. In addition to studying the space environment, basic principles of space flight, spacecraft structure and operation methods, astronauts also need to undergo centrifuge endurance training in simulated spacecraft launch and return conditions, training for working in noisy and vibrating environments, simulated weightlessness training, hypoxia endurance training in pressure test chambers, 360-degree rapid rotation chair exercises to enhance anti-vertigo ability, emergency response training, isolation training for the solitude of space, and 72-hour sleep deprivation training. During centrifuge endurance training, astronauts rotate horizontally in the training chamber, experiencing the outward inertia centrifugal force and the downward gravitational force, which combine to simulate the conditions of increased weight. Simulated weightlessness training is achieved by making the buoyancy experienced by astronauts equal to the gravitational force. (Main reference: https://www.bilibili.com/video/BV1LQ4y1Q7wL/)
Spacesuits can reduce the harm caused by environmental factors such as vacuum, extreme temperature changes, solar radiation, space debris, and micro-dust particles in space. Taking the extravehicular spacesuit as an example, it has functions such as protection, mission execution, and life support. The gold-plated filter window is used to filter harmful radiation and block infrared waves to achieve thermal insulation. The outer protective layer of the pressure suit, made of composite fibers, can withstand attacks from micro-dust and cosmic radiation. The insulation layer, made of aluminum-plated polyester film, utilizes thermal reflection to achieve thermal insulation. The airtight-limiting layer, composed of rubber and polyester, prevents the spacesuit from excessive expansion due to the large pressure difference inside and outside. (Main reference: https://www.bilibili.com/video/BV1Uv4y1D7AJ/)
Astronauts need to exercise in space to prevent osteoporosis. In addition, they also need to undergo psychological training to prevent claustrophobia.
Carrier Rocket-related#
To escape the Earth's gravity and enter the intended orbit, a carrier rocket needs to reach a certain speed, which places high demands on the thrust of the rocket engine. Once the rocket takes off, it is subjected to the influence of tremendous gravity and air resistance, which requires a powerful burst force from the rocket engine. In addition, the rocket engine needs to be lightweight, strong, highly stable, and made of high-quality materials. Currently, China mainly uses the YF-100 rocket engine as the engine for carrier rockets. It adopts the oxygen-rich staged combustion cycle technology, which has the advantages of environmental friendliness, economy, reliability, high thrust, high performance, and reusability. (Main reference: Baidu Baike)
Due to the fact that low-frequency vibrations can cause internal organ movement, interfere with brain waves, and hinder language, limb movement, and decision-making abilities, which seriously endanger the astronauts' lives, strict requirements for vibration suppression are imposed on manned space flight. The 8Hz vibration that occurred during China's manned rocket launch caused great pain to the first astronaut, Yang Liwei. Researchers used energy accumulators that can absorb the energy generated by fuel vibrations and change the frequency of fuel vibrations to suppress the 8Hz vibration. (Main reference: https://www.nsfc.gov.cn/publish/portal0/tab446/info65146.htm)
During the rocket assembly process, in order to avoid trouble and prevent problems during vertical assembly, rocket assembly and testing should adopt the advanced mode of "vertical assembly, vertical testing, vertical transportation," as well as long-distance testing and launch ("three vertical modes"). When fueling the rocket, the amount of fuel to be added (fueling parameters) needs to be calculated based on meteorological conditions. The rocket is first filled with room temperature propellant and then filled with cryogenic propellant to prevent the harmful effects of aerodynamic forces, aerodynamic heating, and acoustic vibration on the satellite. The rocket needs to have a fairing to protect the satellite. (Main reference: Quanzhou Science and Technology Museum Space Exploration Exhibition and Baidu Baike)
Others#
Space rendezvous and docking can be divided into three types: forward, backward, and radial docking. There are four control types for space rendezvous and docking: remote control operations entirely controlled by the ground through telemetry and telecommand, manual operations performed by astronauts under ground guidance, automatic control achieved by combining shipborne equipment with the ground, and autonomous control achieved by shipborne equipment without relying on astronauts or the ground. In order to use the radial port, radial rendezvous and docking are required. The control of attitude and orbit in radial rendezvous and docking is difficult, as well as determining the relative position and attitude. Astronauts' manual control during rendezvous is also challenging. In October 2021, China's first radial rendezvous and docking was completed autonomously by the spacecraft under the command of the guidance, navigation, and control system. (Main reference: https://www.thepaper.cn/newsDetail_forward_14932299)
When the spacecraft return capsule returns to Earth, the gas and materials on the surface of the return capsule will be decomposed and ionized due to aerodynamic heating, forming a plasma layer. Since plasma has the ability to absorb and reflect electromagnetic waves, the plasma layer covering the surface of the return capsule acts as an electromagnetic wave shield. At this time, radio signals from outside the capsule cannot enter, and radio signals from inside the capsule cannot be transmitted to the outside, resulting in a loss of communication between the inside and outside of the capsule. This phenomenon, where communication between the spacecraft and the ground is interrupted when the spacecraft returns to the atmosphere at high speed, is called the blackout phenomenon. For example, the Tianwen-1 lander rover will experience a blackout period of up to 9 minutes during its landing on Mars. Currently, there is no method that can completely solve the blackout phenomenon, but improving the design of the return capsule can alleviate the blackout phenomenon. (Main reference: Baidu Baike)