Preamble:
On January 3, 2020, the China National Space Administration (CNSA) officially announced that the Chang'e-4 lander and the Yutu-2 lunar rover have successfully entered their 25th month of operation. The Chang'e-4 lander and the Yutu-2 lunar rover have been working on the lunar surface for 732 days, and the lunar rover has traveled 600.55 meters, making them the landers and lunar rovers that have been working on the lunar surface for the longest time. The successful implementation of the Chang'e-4 mission not only marks a major breakthrough in China's lunar exploration program, but also contributes valuable scientific data to human exploration of the moon and deep space.
1. Relay satellites play a key role
In the Chang'e-4 mission, relay satellites play a crucial role. Since the rotation period of the Moon is the same as the rotation period, the far side of the Moon is always facing space, so it cannot communicate directly with the Earth, and the ground control center cannot directly communicate with Chang'e-4, so it is necessary to establish a relay communication link between the far side of the Moon and the Earth. As a relay station for information transmission, the relay satellite can receive instructions from the ground control center and transmit them to the Chang'e-4 lander and the Yutu-2 lunar rover, and at the same time can receive data from the far side of the moon and transmit it back to Earth to ensure smooth communication.
In the soft landing mission on the far side of the Moon, the relay satellite needs to communicate with Chang'e-4 for multiple orbit corrections and landing processes to ensure that the lander reaches the far side of the Moon smoothly and safely. In addition, the relay satellite also needs to overcome the tidal locking effect between the Earth and the Moon, receive and transmit signals in a timely and accurate manner, ensure the smooth and stable communication link, and provide reliable communication support for the scientific exploration and observation mission of Chang'e-4.
Second, track experts propose new technologies
Orbit design and control are crucial in the implementation of the Chang'e-4 mission. Since unforeseen conditions such as fuel leaks can have a significant impact on the track and control system, the track design and control scheme needs to be robust and capable of emergency response.
In order to cope with emergencies, orbit experts proposed a joint optimal control technology, which can quickly give an emergency orbit reconstruction plan after encountering unexpected situations during the mission, effectively avoiding potential risks and ensuring that Chang'e-4 can carry out various scientific exploration missions smoothly as originally planned. This technology can realize the effective coordination of orbit design and control, make full use of the performance of each subsystem, optimize the orbit parameters, improve the robustness and adaptability of the system, and meet the needs of scientific exploration missions to the greatest extent under the premise of ensuring the safety of Chang'e-4.
Third, fuel leaks pose a major challenge
During the Chang'e-4 mission, the probe encountered major technical challenges such as fuel leaks. Fuel leakage will not only have a significant impact on the normal operation of the probe, but will also lead to the instability of the probe's center of gravity, which will affect the implementation of orbit control and precision landing.
It is worth noting that the fuel leakage will shift the center of gravity of the probe, which will bring significant challenges to the orbit control and landing process, and the orbit control scheme needs to be redesigned to ensure that the probe can accurately and safely reach the target landing area during the soft landing mission on the far side of the moon. To this end, relevant technicians proposed a new orbit design and control scheme, making full use of the probe's multiple propulsion systems and variable thrust engines to achieve accurate thrust output in a complex and changeable gravitational environment, effectively coping with the challenge of the probe's center of gravity shift, and ensuring that Chang'e-4 can independently choose the landing site to achieve precise obstacle avoidance and soft landing.
Fourth, the detector has the ability to detect independently
As an important lunar probe, the Chang'e-4 lander has a number of autonomous exploration and self-diagnosis capabilities. In the process of carrying out scientific exploration missions, various unexpected situations may be encountered, such as equipment failure, communication interruption, etc., which will have a certain impact on the work of the probe.
In order to cope with these challenges, the Chang'e-4 lander is equipped with advanced autonomous detection and telemetry technology, which can timely diagnose and judge possible faults, and give corresponding system reconstruction plans to ensure that the probe can successfully complete various scientific tasks.
Epilogue:
The successful implementation of the Chang'e-4 mission has set a glorious milestone for the development of the mainland's aerospace industry, and has also provided rich scientific data and valuable experience for mankind's exploration of the moon and deep space. In the future scientific exploration, we have reason to believe that the successful experience of Chang'e-4 will provide an important reference for the implementation of subsequent exploration missions, and at the same time, it will also encourage more scientific researchers to devote themselves to the aerospace industry and contribute to the exploration of the universe by mankind.