Mission Type: Flyby, Orbiter

Launch Vehicle: Mu-3SII-5 (No. 5)

Launch Site: Kagoshima, Japan, Launch Complex M1

Spacecraft Mass: 197 kg fully fueled (143 kg Hiten + 12 kg Hagoromo + 42 kg hydrazine fuel)

Spacecraft Instruments: Hiten: Cosmic dust detector

Hagoromo: None

Spacecraft Dimensions: Hiten: cylinder 1.4 m in diameter and 0.8 m high. Hagoromo: 26-faced polyhedron, 36 cm between opposite faces

Spacecraft Power: solar cells

Maximum Power: 110 W

Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, Monographs in Aerospace History No. 24, by Asif A. Siddiqi

National Space Science Data Center, http://nssdc.gsfc.nasa.gov/

This two-module Japanese spacecraft was designed to fly past the Moon and release an orbiter. It was the first Japanese lunar mission and also the first robotic lunar probe since the flight of the Soviet Luna 24 in 1976.

Muses-A (for Mu-launched Space Engineering Satellite) was launched into a highly elliptical Earth orbit that intersected the Moon's orbit. After launch, the spacecraft, which was renamed Hiten, returned technical data on trajectory and optical navigation from an onboard computer. The cosmic dust experiment was jointly designed with Germany.

On 18 March 1990, the spacecraft approached the Moon to a range of 16,472 kilometers and then released a small 12-kilogram satellite named Hagoromo into lunar orbit. Initial orbital parameters were 22,000 x 9,000 kilometers. Although the maneuver successfully demonstrated the use of the swingby technique to enter lunar orbit, communication with Hagoromo was lost shortly after release.

Hiten, on the other hand, continued on its trajectory, simulating the orbital path of the proposed Geotail spacecraft that was to study Earth's magnetic tail. On 19 March 1991, Hiten flew by Earth at a range of 126 kilometers and conducted the first aerobraking maneuver by a deep-space probe, which slowed it by 1.7 meters per second. On 2 October 1991 Hiten was temporarily captured by the Moon and then put into a looping orbit which passed through the L4 and L5 stable libration points to look for trapped dust particles. No obvious increase was found.

During its eleventh flyby of the Moon on 15 February 1992, Hiten swung into lunar orbit. On 10 April 1993, it was deliberately crashed into the lunar surface.


Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.

Related News