Kaguya (SELENE)
Kaguya was a comprehensive Japanese lunar orbiter carrying a large suite of instruments and two small relay satellites.
The mission in three questions
- What does a globally consistent high-resolution topographic dataset reveal about lunar basins and crust?
- How does far-side gravity differ when tracking geometry is improved by relay satellites?
- What subsurface and compositional structures can orbital radar and spectroscopy detect?
Mission purpose and context
Kaguya, also known as SELENE, was one of the most comprehensive lunar orbital missions since Apollo. It combined a main orbiter with two smaller satellites to study global topography, composition, gravity and the lunar environment.
Spacecraft and mission architecture
The main spacecraft carried a broad instrument suite including terrain and multispectral cameras, laser altimetry, radar sounding, spectrometers and plasma instruments. The relay and VRAD satellites improved gravity-field measurements, especially on the far side where direct Earth tracking is impossible.
Payload and measurement highlights
- Terrain Camera, Multiband Imager and Spectral Profiler mapped morphology and composition.
- The Lunar Radar Sounder investigated subsurface structure.
- Laser altimetry produced detailed global elevation data.
- Gravity and radio-science experiments used the main orbiter and subsatellites to improve far-side gravity knowledge.
- Plasma, magnetic and particle instruments measured the environment around the Moon.
Flight and surface operations
Kaguya entered lunar orbit in October 2007 and conducted global observations until its controlled impact in June 2009. The mission returned high-definition video as well as extensive scientific datasets.
Mission sequence
- 14 September 2007: launched as SELENE, later widely known as Kaguya.
- Entered lunar orbit in October and deployed two small subsatellites supporting relay and radio-science measurements.
- Completed global mapping through 2009 before the main spacecraft was deliberately impacted.
Science and measurements
Its laser altimeter produced detailed global topography, radar sounding investigated subsurface structures, and gravity observations improved understanding of farside mass distribution. Imaging and spectroscopy strengthened global geological and compositional maps.
What changed because of this mission
Kaguya supplied reference datasets used in lunar geology, geodesy and landing-site studies and demonstrated the value of coordinated main-spacecraft and relay-satellite measurements.
Mission outcome
It returned detailed topography, gravity, composition and high-definition imagery that improved understanding of lunar origin and evolution.
The outcome should be read against the mission's actual objectives and architecture. Multi-element missions can have different results for an orbiter, lander, rover or sample-return stage, while a shortened mission can still return important science or demonstrate a critical technology.
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Primary reference
JAXA - Kaguya SELENE. Kaguya mission architecture and lunar observations.