Japan launched the Kaguya spacecraft toward the moon on September 13, 2007, beginning a mission to map the lunar surface in high definition and study the moon's origin and evolution. The Japan Aerospace Exploration Agency (JAXA) built Kaguya, also known as SELENE (Selenological and Engineering Explorer), as the country's first large-scale lunar mission and the most ambitious moon orbiter since the Apollo era.
Kaguya carried a suite of scientific instruments, including a high-definition television camera that returned stunning images and video of the lunar surface. The spacecraft also used a laser altimeter to measure the moon's topography, a radar sounder to probe beneath the surface, and a magnetometer to study the lunar magnetic field. Its observations were designed to improve understanding of the moon's geological history and internal structure.
The mission was notable for its use of two small sub-satellites, Okina and Ouna, which were released into polar orbits around the moon. These relay satellites allowed Kaguya to maintain continuous communication with Earth while mapping the far side of the moon, a region that had been less thoroughly studied. The dual-satellite system also enabled precise measurements of the moon's gravity field, which scientists used to refine models of the lunar interior.
Kaguya entered lunar orbit in October 2007 and operated for about 20 months, until it was intentionally crashed into the moon's surface in June 2009. During its mission, the spacecraft returned a wealth of data and thousands of high-resolution images, including the first high-definition video of the moon from orbit. The mission helped identify potential resources and landing sites for future exploration.
The launch of Kaguya marked a significant step in Japan's space program and contributed to a renewed international interest in lunar exploration. Its success demonstrated the capability of JAXA to conduct complex planetary missions and paved the way for subsequent lunar orbiters, including NASA's Lunar Reconnaissance Orbiter and India's Chandrayaan-1, which launched in the following years.
Kaguya's high-definition imagery and scientific data remain valuable to researchers today, offering a detailed record of the lunar surface and its environment. The mission also inspired public engagement with space science through its breathtaking views of Earthrise and the lunar landscape, reinforcing the moon's enduring role as a target for scientific discovery and human exploration.