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LUNAR-A was the first Japanese lunar exploration mission planned to be launched in 2004. Its mission plan was to explore the internal structure of the Moon by two penetrators (spear-type instruments) to form an observation network of seismometers and thermal flowmeters. The development of the penetrators, however, took a great deal of time, even though the technology was almost complete. The fact that the electronic components used on the mothership to carry the penetrators were obsolete and adhesives hardened were also problems. Thus, regrettably, we had to cancel the LUNAR-A project in early 2007.

Mission Profile

Objectives Study internal structure, composition and origin of the Moon by the following observations.
  • Observe moonquakes and heat flow by inserting penetrators into two locations on the lunar surface
  • Observe the lunar surface by imaging camera, etc.
Configuration Weight 540 kg (including fuel)
Shape Approx. 1.2 × approx. 1.2 × approx. 1.3 m
Approx. 3.8m long from end to end of solar array paddle
Equipped with two of penetrators with approx. 80 cm high and 16 cm diameter

[Click image for enlargement]
Orbit Type of Orbit Orbit around Moon
Scientific Instruments Two-axis lunar seismometers, heat-flow probe, etc. (installed on the penetrators) Lunar-imaging camera (installed on the spacecraft)