Source: China Aerospace News
At 20:34 Beijing time on August 23, the Indian Chandrayaan-3 probe successfully soft landed in the area near the south pole of 69.37 degrees south latitude and 32.35 degrees east longitude of the moon, making India the fourth member of the "lunar landing club". Looking back on the journey to the moon for more than 1 month, what are the characteristics of the mission progress of the Chandrayaan-3 probe? What state-of-the-art instruments are equipped? Throughout India's lunar exploration history and future planning, what missions and dreams does it hold on India's spaceflight?
The relay carries the dream of lunar exploration
In fact, "Chandrayaan-3" is not the first time that Indian aerospace has looked at the moon, and it can be said that India's lunar exploration road has experienced twists and turns before.
In October 2008, India launched its first lunar probe, Chandrayaan-1, the first deep space mission in Indian spaceflight. The lunar probe consisted of an orbiter and an impactor rover, which meticulously surveyed the surface and interior of the moon by patrolling and hitting the lunar surface, and sent back a large amount of data. By analyzing these findings, scientists have preliminarily determined that there are solid water ice resources on the moon. This is also the most important discovery of Chandrayaan-1.
Although Chandrayaan-1 failed at the end of August 2009 due to overheating of internal instruments, lost contact with the ground and forced the termination of its mission, it basically achieved the desired goal of Indian spaceflight.
India's second lunar mission was more challenging — after the Soviet Union, the United States, and China, probes attempted soft landings on the lunar surface. On July 22, 2019, the Chandrayaan-2 probe was launched. It includes an orbiter and a lander, and its main mission is to orbit the moon and safely land on the south pole of the moon, collecting samples of water ice, rock and soil. Unfortunately, the lander lost contact about 2.1 kilometers from the lunar surface and was later found to have crashed.
However, we cannot consider Chandrayaan-2 a complete failure. Its orbiter is still orbiting the moon, continuing to provide data for lunar scientific research and future exploration missions, and successfully establishing a communication connection with Chandrayaan-3. In addition, many scientific instruments on the "Chandrayaan-2" were independently developed by India, which exercised the development of India's aerospace supporting industry and accumulated experience for the next lunar exploration mission.
Ambition leads to success
According to public information, the Chandrayaan-3 probe includes a propulsion module, a lander and a lunar rover.
Specifically, the propulsion module has a box-like structure, installed with large solar panels and communication equipment, and acts as a relay satellite during the flight to the moon.
On the way to the moon, the propulsion module drove the probe to raise the altitude of low earth orbit five times in a row, entered the earth-moon transfer orbit on August 1, entered the lunar orbit on August 5, and then slowly lowered the orbital altitude several times to prepare for landing on the moon.
From another point of view, the orbital design of "Chandrayaan-3" can save fuel, but it also reflects the insufficient capacity of India's LVM3 rocket, which increases the risk of excessive fuel consumption for orbit change, and there are certain lucky factors for successful moon landing.
It is worth noting that the lander of Chandrayaan-3 is more than 200 kilograms heavier than its predecessor, reflecting its loading equipment and security measures upgraded. After a successful landing, the lander needs to use a ramp to release the 26-kilogram Pragian lunar rover to officially explore the lunar surface.
The 6-wheeled solar-powered lunar rover will maintain communication with the Earth team in the future with the help of the lander and the Chandrayaan-2 orbiter. It is equipped with a laser-induced breakdown spectrometer and a α-particle X-ray spectrometer. Among them, the X-ray spectrometer protrudes from the front end of the rover and rotates 90 degrees to study the material below, reveal the chemical composition of the lunar surface, and help scientists determine the elemental composition of the soil and rocks around the landing area.
The lander also carried a seismometer and planned scientific experiments to detect moonquakes, hoping to get clues about the moon's internal structure. In addition, Chandrayaan-3 detected plasma produced by charged particles of solar radiation on the lunar surface for the first time and carried out lunar in situ thermal probe experiments. Through laser pulses from various devices, scientists are expected to better study the gravitational effects of the Earth-Moon system and the interior of the Moon, understand the physical characteristics of lunar soil such as thermal conductivity and density, and guide future missions to explore lunar resources.
From the perspective of India's entire lunar exploration project planning, the Indian space agency has high hopes for the "Chandrayaan-3", and confidently said as early as the launch that it will prove India's strength in technological innovation and scientific research as an "emerging technology power" and help India establish a "leading position" in the field of global space science and technology.
The challenges ahead are even greater
"Chandrayaan-3" played an important role in India's lunar exploration program. Previously, India proposed a lunar exploration mission plan consisting of four stages: orbit exploration, landing exploration, lunar surface sampling and sampling return. Among them, "Chandrayaan-1" realized the orbital exploration mission, and also carried out lunar surface impact detection; The goal of "Chandrayaan-2" is to master the soft landing technology on the lunar surface and carry out patrol exploration, which unfortunately failed and was handed over to "Chandrayaan-3".
In addition, India and Japan are jointly promoting the development of lunar polar exploration missions, although not officially approved, but has been called "Chandrayaan-4" by the Indian side, and is expected to be launched in 2026~2028. According to the plan, after landing near the south pole of the moon, Chandrayaan-4 will use a drilling rig developed in India to drill samples of the lunar subsurface and heat it to analyze whether it contains volatiles, especially water ice resources. The lander will also validate lunar night survival technology, with a design lifespan of up to 6 months to support more complex lunar exploration missions in the future.
In order to improve its space autonomy, India is demonstrating the Chandrayaan-5 project, which could be launched around 2030. Its positioning and function are similar to "Chandrayaan-4", which is also planned to land on the south pole of the moon, but India will lead the mission, develop a large lunar rover, drill samples for in situ research.
Further, India is also considering a long-term mission plan for lunar sampling and return, possibly named Chandrayaan-6, but it will be implemented after 2030.
It is not difficult to see that India's lunar exploration plan has chosen the macro development idea of "circling, falling and returning", but India has focused on planning a sampling and exploration mission in the south pole region of the moon according to its own capabilities and international cooperation environment.
In addition to the above-mentioned lunar exploration cooperation with Japan and seeking to carry US and European instruments, India has also signed the "Artemis Agreement" led by the United States, and will strengthen cooperation with the United States in lunar exploration. For example, the selection of the landing site for Chandrayaan-3 is the result of Indian researchers weighing high-resolution photos and data from the Chandrayaan-2 orbiter and the U.S. Lunar Reconnaissance Orbiter. During the Lunar Voyage 3 landing, NASA's Deep Space Network provided support from multiple large antennas.
In the future, India may have in-depth exchanges with the West in the field of lunar exploration, introduce key technologies, develop more advanced lunar probes, and even do not rule out the development of next-generation rockets and spacecraft that integrate Western technologies to participate in manned lunar missions. In this way, as long as it persists in advancing, the prospects of India's lunar exploration project are still worth looking forward to.
Text/Fan Shanshan