The moon, shining brightly in the night sky, is one of the closest and most familiar celestial bodies to us, along with the sun. Because it is the nearest celestial object to Earth, the moon is expected to play a central role in humanity’s future endeavors in space exploration. It is envisioned as a base of operations for deeper space missions and as a source of materials for building space infrastructure in lunar orbit—such as space factories, power stations, and habitation facilities. Furthermore, the moon is expected to serve as a launch base for human missions to planets such as Mars.
To date, over 100 lunar missions have been conducted, and in the near future, human missions with extended stays are planned. Broadly speaking, the roughly 60 years from the beginning of lunar exploration up until around 2020 can be considered the era of “scientific exploration and study of utilization” conducted by national agencies. The decades since then mark the era of “preparation for practical lunar utilization", with increasing involvement from private enterprises.
From the 1960s to the early 1970s, the United States and the Soviet Union (as it was known at the time) led a period of intense lunar exploration—the first lunar exploration boom. This was driven not only by scientific curiosity about the moon's mysteries but also by a fierce space race between the two nations to demonstrate national prestige. In 1969, the United States achieved the first human landing on the moon through the Apollo program. Once this competition subsided, lunar exploration virtually ceased for nearly 20 years.
In the 1990s, driven by the slogan “Back to the Moon,” lunar missions resumed with a focus not only on scientific research but also on assessing the moon’s potential for future use. Countries including Europe, the United States, Japan, China, and India launched a new wave of lunar projects, leading to a second lunar exploration boom that continued actively until around 2010.
In Japan, just before the beginning of the second lunar exploration boom, the engineering test spacecraft Hiten reached the Moon in 1990 and released a small satellite, Hagoromo, into lunar orbit. Later, from 2007 to 2009, the lunar orbiter "KAGUYA", which was the largest lunar probe since the Apollo program at the time, conducted extensive observation and investigation of the moon. These efforts produced an enormous trove of data on the moon’s composition, topography, gravity, magnetic field, and environment, which researchers in Japan and abroad continue to analyze.
Thanks to these analyses, we have made significant scientific progress on the moon’s origin and evolution—such as confirming the existence of a global magma ocean, modeling the scenario of surface solidification, understanding the causes of the moon’s near-far side dichotomy, discovering evidence of an ancient strong magnetic field, and exploring the current state of its interior. Data essential for future lunar development was also obtained, including three-dimensional topography, resource maps, subsurface structures, illumination zones, and polar water ice deposits. Furthermore, Japan acquired advanced technological capabilities in orbital insertion and controlled impact descent, which are foundational for future missions.
Although Japan did not conduct further lunar missions for nearly 15 years after Kaguya, in 2024, the SLIM (Smart Lander for Investigating Moon) mission successfully achieved Japan’s first lunar landing, demonstrating precision landing technology by touching down exactly where intended. While Japan’s lunar exploration was once driven solely by government-led projects, it is now being promoted by a broader community that includes industry players .
Since around 2010, after the intense wave of orbital missions, the global trend has shifted toward lunar landings. China has steadily advanced its lunar program through a phased approach: landing on the near side, then the far side, and eventually achieving sample return from the lunar surface, establishing a strong presence in lunar exploration. Since around 2020, efforts toward soft landings on the Moon have continued in various countries, including by private companies such as Japan’s ispace with its HAKUTO-R mission. However, landing on a celestial body without an atmosphere requires sophisticated thrust control, and success rates remain relatively low. India’s ISRO succeeded in landing in 2023, and as mentioned, Japan's SLIM achieved a successful landing in 2024.
Looking ahead, we are entering a new era—shifting from unmanned lunar exploration to manned lunar development. Under the Artemis Program, led by the United States and joined by Europe and Japan, a crewed lunar orbit mission is planned for 2026, followed by a human landing in 2027. However, space policy has been somewhat fluid since the Trump administration, so these schedules may be subject to change. Meanwhile, China—alongside Russia—is planning to establish a lunar base in the 2030s, under the ILRS (International Lunar Research Station) framework. While the realization of such bases will still take time, the establishment of a manned lunar station will mark the beginning of full-scale lunar development, contributing to the long-term sustainable development of human society.
Now, the frequently cited catchphrase in lunar science—“Unraveling the origin and evolution of the Moon”—has accompanied nearly every lunar exploration mission. But how much progress has actually been made? While a vast amount of scientific data has been collected and many aspects of the Moon’s evolutionary processes have been revealed, a definitive model for its origin has yet to be established. It may only be through extended fieldwork by scientists staying at a crewed lunar base that a conclusive understanding will finally be achieved.