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M-3SII

Targeting Halley's comet which made an appearance in 1985 after 76 years, ISAS started the development of the fifth generation Mu-launch system, M-3SII in 1981. The booster is a descendant of the M-4S first flown in 1970. It used the first stage of M-3S. however, the rest of the stages were replaced by new ones to enhance its payload capability. M-3SII-1 and -2, with a fourth kick stage, sent the first and second Japanese interplanetary probes, SAKIGAKE and SUISEI in 1985 toward encountering orbit with Halley's comet. Seven launches of M-3SII Iaunch system out of eight have been successful up to now.

The only flight during 1993-1994 occurred on 20 February 1993 when the 420-kg Astro-D (aka Asuka) X- ray observatory was inserted into an orbit of 534 km by 647 km with an inclination of 31.1 degrees. The maximum lift capacity for the M-3SII is approximately 800 kg into a 250 km circular, a 31 degree orbit (References 116 and 117).

The M-3SII is a 3-stage, all solid-propellant launch vehicle with two strap-on boosters and a family of optional fourth stages which are tailor made for specific mission profiles. All four stages as well as the strap-on boosters are manufactured by the Nissan Motor Company. In addition to LEO missions, the M-3SII has placed spacecraft on Earth escape trajectories (Sakigake and Suisei in 1985) and into extremely high altitude orbits with apogees beyond lunar distances (Muses-A in 1990). The final flight of the M-3SII took place in 1995 in support of the German Japanese-Russian microgravity recoverable satellite program, EXPRESS.

M-3S-II (Japan)

Background Information First Launch: January 1985 Flight Rate: Typically one every other year Launch Site: Uchinoura (Kagoshima), Japan Capability: 1,720 lb to LEO; 440 lb to GEO History Japanese rocket program started in late 1950s Developed and launched by the Institute of Space and Astronautical Science (ISAS) M-3S-II is latest version of the M-family of vehicles Description Three-stage solid vehicle with two strap-on boosters Stage 1 burns CTPB solid propellant, generating 286,500 lb of thrust Stage 2 burns HTPB composite grain fuel, generating 117,800 lb of thrust Stage 3 burns HTPB composite grain fuel, generating 29,700 lb of thrust Two strap-on boosters burn CTPB composite grain fuel in a SB-735 motor, generating 73,500 lb of thrust each Profile Length: 91.1 ft Launch Weight: 135,700 lb Diameter: 4.6 ft Liftoff Thrust: 360,100 lb Payload Fairing: 22.5 ft x 5.4 ft

The vehicle M-3SII-1 is described as follows