The Indian Space Research Organisation's (ISRO) Chandrayaan-3 probe successfully entered lunar orbit in the early hours of August 7, marking its first and milestone journey to the moon's south pole. India** and netizens cheered for this, believing that India's aerospace industry has made great progress. But in fact, the Chandrayaan-3 mission is far from complete, and it still needs to face two more difficult and critical stages, if it can be successfully achieved, India will become the first country in the world to land at the south pole of the moon, surpassing the three major space powers of China, the United States and Russia.
Chandrayaan-3's orbit entry process is not simple, it not only has to slow down and brake, but also change orbit, because its target landing site is a high latitude of 69 degrees south, so its orbit around the moon inclination is much larger than that of ordinary probes. This requires ISRO's track tracking and control and orbit change control technologies to be very accurate and reliable, and judging from the ** published by ISRO, they have reached a very high level.
But this is only the first step for Chandrayaan-3, which will also need to carry out orbital and orbital relay operations, correcting its orbit from a large elliptical orbit of 164 km x 18,074 km to a roughly circular orbit of 100 km x 100 km, so as to prepare it for subsequent landings. This operation is also very demanding, requiring the assistance of multiple radio telescopes, and ISRO has also received help from the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). After the orbit is successful, the Chandrayaan-3 propulsion module will be detached and used as an orbiter and relay communication equipment to provide data transmission and navigation services for the lander and rover.
Finally, the Chandrayaan-3 lander and rover will land on the lunar surface on August 24, which is the hardest step and the most error-prone one. The lander has to descend from an orbit of 100 x 15 km, gradually slow down, adjust the direction, choose a suitable landing site, and finally make a soft landing at coordinates 69367ºs, 32.Location of 348 e. This process must be dynamically decelerated throughout the process, and cannot rely on the moon's atmosphere, and must be controlled by the spaceborne computer autonomously, not by the ground remote control, because there is a communication delay of about 2 seconds between the earth and the moon. This is a huge test of India's software and hardware capabilities, and any missteps could lead to a lander crash.
If the lander can land safely, the rover will have to "climb down" from the lander and start exploring the lunar surface. The rover weighs 26 kilograms and is shaped like a pyramid, and its rail design differs from that of China's Chang'e series probes and appears to be flatter and more spacious. The tasks of the lunar rover are to drive on the lunar surface, shoot **, measure temperature, analyze soil composition, etc. It can only work during the moonlit day, because the temperature on the moonlit night is as low as minus 180, and it does not have enough energy and heat preservation capacity. Chandrayaan-3 will land on the ninth day of the lunar calendar, and there are still more than ten days before the moonlit night, during which time the rover will try to complete its mission as much as possible.
The Chandrayaan-3 mission is not India's first lunar exploration, its predecessor, Chandrayaan-2, attempted to land at the moon's south pole in 2019, but lost signal during the descent and was confirmed to have crashed. The investigative report revealed that the crash of Chandrayaan-2 was caused by a software glitch, and the lander's engine was under-throttled, resulting in excessive speed beyond the correction of the onboard software, and finally hit the lunar surface. This is a very embarrassing and regrettable result for India, a software powerhouse, and it also brings great pressure and challenges to ISRO.
Chandrayaan-3's lander and rover were designed differently from Chandrayaan-2, with the lander's engines reduced from five to four, and the landing deceleration engine in the middle was eliminated to improve the stability of the landing. But it also means that the four variable thrust engines have to take on a much larger workload, and if one of the engines fails, or if the software is written incorrectly, it could cause Chandrayaan-3 to repeat the mistakes of Chandrayaan-2.
Chandrayaan-3 is targeting the south pole of the moon, which is a place of global concern because there is a possibility of water ice at the south pole of the moon, which is of great significance for future lunar bases and lunar resource development. The moon's south pole also has some perpetual day zones that continuously receive sunlight and provide energy and temperature. Therefore, the south pole of the moon is the preferred location for lunar exploration, and in addition to India and Russia, China's Chang'e-7 and the American Artemis program will also go to the south pole of the moon to compete and cooperate. But in this race for lunar exploration, India and Russia are not strong enough to compete with China and the United States, they still have a long way to go, and the Chandrayaan-3 mission is only the beginning, but also a test.