The Russian unmanned probe Luna-25, headed for the lunar south pole, deviated from its orbit and crashed into the lunar surface two days before its scheduled landing. Russia, which was at the forefront of space exploration during the Soviet era with the first successful human spaceflight, failed to land a man on the moon, a feat that was accomplished by China in 2019. Luna 25 was designed to land near the north of the Boguslavsky Crater on the moon’s south pole to conduct a year-long mission of exploring its interior structure and resources. Reuters reported on the 21st (local time) that “this failure underscores the decline of Russia’s space technology since the Cold War.”
Moon exploration is characterized by the complexity of rocket launch from Earth and the moment of lunar landing. While investments in space launch vehicle technology have increased launch success rates, the technical barriers to lunar landings have not. Over the past four years, Israel, Japan, and India have embarked on lunar exploration missions, achieving successful launches to lunar orbit, yet facing difficulties in landing. India’s Chandrayaan-3, launched in August, will attempt another lunar south pole landing on the 23rd.
◇ Key Challenge: “Lunar Surface Landing”
In the past, all U.S. Apollo lunar landers touched down on the relatively flat “near side” of the moon. Urgency to be the first to send humans to the moon’s surface, amidst the space exploration rivalry with the Soviet Union, led to the selection of areas with relatively easy access for spacecraft. However, as lunar exploration resumes more than 50 years later, countries around the world are now targeting the more challenging “far side” and the moon’s south pole. This is due to their higher economic value, including resource extraction possibilities.
The “far side” of the moon, which recent exploration is focusing on, has a rugged surface and is further complicated by the existence of “permanently shadowed regions” that are untouched by sunlight, making it challenging to secure landing sites. Particularly, the moon’s south pole remains an uncharted territory for humanity. The moon’s south pole is filled with numerous craters, making it one of the most rugged places on the lunar surface.
The moon’s south pole is one of the most challenging areas for spacecraft to land on. Frequent impacts of meteoroids on the lunar surface create fine dust that hinders visibility. With no atmosphere on the moon, any misjudgment in landing speed could result in a collision with the lunar surface due to freefall. To prevent this, the altitude must be calculated by shooting lasers toward the moon’s surface and measuring the time it takes for the reflection to return. However, this “laser altimeter” method is still in its early stages of development, even in space-advanced nations like the United States and Europe. Some experts say that even the United States may find landing on the moon’s south pole challenging. In April, a Japanese spacecraft attempting a lunar landing also crashed due to altitude calculation errors.
Exploration probes heading towards the moon’s south pole face communication delays due to the distance from Earth, making real-time control impossible. In particular, the south pole of the moon cannot directly communicate with the Earth, only relay communication using orbiters is possible, which further delays communication. Slowing down the speed isn’t the only concern. Near the lunar surface, retro-thrusting can cover the spacecraft with lunar soil that creates static electricity, so the engine must be turned off at an altitude of around 5 meters and the landing should be executed in a dropping manner. Static electricity often becomes the cause of hardware failures in landing systems.
Cheon Yee-jin, Head of GEO-Satellite Programs Office at the Korea Aerospace Research Institute, stated, “The process of retrieving SpaceX’s reusable rockets on Earth involves providing precise signals to the landing point, enabling accurate altitude and speed calculations,” adding, “However, unlike on Earth, the moon lacks landing guidance devices, making the task multiple times more challenging.”
◇ Russia’s Decline in Space Technology
Russia, which successfully achieved the world’s first unmanned lunar landing in 1966, failing 57 years later, also signifies the decline of its space technology. After the end of the Cold War, Russia shifted its focus from celestial exploration like the moon to more immediate investments in satellite launches and space stations. While recent space development competitions have driven Russia back into lunar exploration, the gap from the past remains challenging to fill. Experts in the space industry state that “historically, space development relied on the knowledge of scientists rather than records,” and added, “the disappearance of scientists experienced in lunar exploration over time contributes to the weakening of Russia’s competitive edge.”
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