First Launch: 1966-10-31. Last Launch: 1995-01-15. Number: 25 . Longitude: 131.08 deg. Latitude: 31.25 deg.
Examined solar radiation, thermospheric structure. SRATS (Solar and Thermospheric Radiation Satellite) is the third Japanese scientific satellite, to study the intereffects of solar radiation and the thermosphere of the earth. National name: Taiyo. Launch time 0525 GMT.
Tentative name before launching: MS-T3. Launching organization: Institute of Space and Aeronautical Science, University of Tokyo. Radio frequencies: 136.725 MHz, tracking; 400.500 MHz, telemetry. Active life: two weeks. Function: (1) Test of the overall p erformance of the newly developed launch vehicle, M-3H-1. (2) Experiment of magnetic stabilization. (3) Observation of ultraviolet radiation.
Auroral studies. Active life - two years. Function: 1) Observation of wide angle global auroral pictures using UV television camera. 2) Spectrophotometry of ultraviolet air glow. 3) Observation of the energy spectrum of photoelectrons and auroral electrons. 4) Mass spect rometry of the ionized atmospheric species in the thermosphere. 5) Measurements of density and temperature of ambient electrons in the thermosphere. 6) Observation of electromagnetic and plasma waves and the emission associated with auroral phenomena.
Launching organization: Institute of Space and Aeronautical Science, University of Tokyo. Stimulated plasma wave experiment, natural plasma wave measurement, plasma parameter measurement by VLF Doppler technique, electric field probe and plasma density me asurement, energetic particle analysis, and controlled electron beam emission experiment. Characteristics: weight 90.5 kg, configuration - polyhedron with 38 faces, height 0.6m , diameter 0.75m, attitude control spin stabilization, life two years.
Soft X-ray telescope. Launching organization: Institute of Space and Aeronautical Science, University of Tokyo. Function: Observation of X-ray radiation of celestial bodies with good time resolution over a wide spectrum range. Characterstics: weight 96 kg, configuration regula r octagonal prism, height 0.66 m, diameter 0.76m, spin stabilized. Expected life 2 years.
X-ray experiments. Astro-B (Tenma). Launch 0510 GMT. Launching organization: ISAS (Institute of Space and Astronautical Science). X-ray observation of X-ray stars in our galaxy as well as X-ray galaxies using a scintillating proportional counter, a transient X-ray source mo nitor, an X-ray foucsing collector, a radiation belt monitor, a gamma ray burst detector and a star sensor.
Optical investigations of ionosphere. EXOS-C (OHZORA). Optical study of the stratosphere and middle atmosphere. Study of the specific phenomena of the ionospheric plasma over the southern Atlantic geomagnetic anomaly zone which was discovered by the third scientific satellite 'TAIYO'. Launch vehicle Mu-3S-4, launching organization ISAS (Institute of Space and Astronautical Science). Launch time 0800 GMT.
Sakigake ('Pioneer') was a test spacecraft similar to Suisei (Planet-A). Objectives were :verification of fundamental technology related to interplanetary missions, including deep-space communication, attitude control, attitude determination; study and observation of solar wind and plasma waves and interplanetary magnetic field. It carried three instruments to measure plasma wave spectra, solar wind ions, and interplanetary magnetic fields. The spacecraft was spin-stabilized at two different rates (5 and 0.2 rpm). It was equipped with hydrazine thrusters for attitude and velocity control, star and sun sensors for attitude determination, and a mechanically despun off-set parabolic dish for long-range communication. Launched into an initial heliocentric orbit with a period of 318.8 days, at 151.4 x 121.9 million km (0.815 x 1.012 AU), 1.439 degree inclination. Flew by Comet Halley on its sunward side at a distance of about 7 million kilometers on March 11, 1986. It later made an Earth swingby on January 8, 1992 with a closest approach of 88,997 km. This was the first planet-swingby for a Japanese spacecraft. During the approach, Sakigake observed the geotail, with passage occurring at 290 Re on 14 June 1993 before ISTP's multi-spacecraft investigation of that region. The second Earth swingby was on June 14, 1993 at 40 Re, and the third on October 28, 1994 at 86 Re. Almost no hydrazine remained so no further maneuvers were accomplished. Telemetry contact was lost on 15 November 1995 at a distance of 106 million km. Future mission planning had included a 23.6 km/s, 10,000 km flyby of Comet Honda-Mrkos-Pajdusakova on Feb 3, 1996 (approaching the nucleus along the tail) some 0.17 AU from the Sun, and a 14 million km passage of Comet Giacobini-Zinner on Nov 29, 1998.
Rendezvoused with comet Halley 3/8/86. Solar Orbit (Heliocentric). PLANET-A (SUISEI). Launch time 2333 GMT. Imaging of the hydrogen coma of Halley's comet by the hydrogen Lyman alpha line. Measurement of the solar wind in the cruising phase and in the vicinity of the comet. Launching organiza tion ISAS. Heliocentric orbit parameters 282 days, inclination 0.888 deg, 151.42 x 100.5 million km (1.0122 x 0.6718 AU).
MUSES-A was renamed Hiten after launch. It developed of lunar swingby techniques for future missions and ejected a lunar orbiter. Launching organization ISAS. On 1990 Jan 25: Period 6.665 days, inclination 30.63 deg, 262.49 x 286182.72 km. On 1992 Feb 17: Period 4.53 days, inclination 38.90 deg, perilune 2289.67 km, apolune 49013.93 km.
At first thought not to have reached orbit. Later the re-entry vehicle was discovered in Ghana having reentered and deployed its parachute on January 15. At T+103 sec, during the second stage burn, the vehicle veered off course. The payload service module entered a 110 x 250 km x 33 degree orbit, instead of the intended 270 x 380 km and re-entered on its second orbit. The re-entry capsule was found later in Ghana. A failure of the second stage attitude control system was blamed, although it was considered likely that the payload was too heavy for the vehicle, being twice the mass of earlier MU-3S payloads.