Mission Overview

After launch, the sixth Japanese satellite, CORSA-B, was officially renamed Hakucho, the Japanese word for swan. The spacecraft had the shape of an octagonal rightprism, with maximum width 80 cm and height 65 cm, and was spin-stabilized at a rate of 5 to 8 rpm. The spin axis was maneuvered by means of magnetic torquing. Eleven X-ray detectors of various specifications were devoted to the observation of cosmic X rays. Four detectors had fields of view perpendicular to the spin axis and scanned over a wide region of the sky in search of X-ray novae and transients. The other seven detectors had FOVs along the spin axis and were used to study selected celestial objects. Observational data could either be telemetered back in real-time or stored in an onboard data-recorder. Telemetry frequencies were 136.725 MHz at 500 mW and 400.450 MHz at 100 mW. The scientific objectives of Hakucho were (1) a systematic survey and watch of short-lived X-ray phenomena, (2) observations of selected X-ray sources with a wide spectral coverage (0.1 to 100 keV), (3) study of short-term variabilities and pulsations of X-ray sources, and (4) study of the X-ray sky in the sub-keV range.

Launch Date: 1979-02-21 at 05:00:00 UTC
Launch Vehicle: M-3C
Launch Site: Uchinoura Space Center, Japan
Decay Date: 1985-04-15
Trajectory Details
Type: Orbiter
Central Body: Earth
Epoch start: 1979-02-21 05:00:00 UTC
Orbital Parameters
Periapsis 421.0 km
Apoapsis 433.0 km
Period 93.0999984741211 minutes
Inclination 29.899999618530273°
Eccentricity 8.81000014487654E


Monitor of X-Ray Sources

This experiment located and monitored X-ray burst sources and other variable X-ray sources, over the energy range 1 to 100 keV, using rotating modulation collimators and other collimators.

Diffuse Soft X-Rays and Soft X-Ray Sources

This experiment surveyed the sky and monitored transient soft X-ray sources, in the energy range 0.1 to 2 keV, by means of gas-flow proportional counters with thin polypropylene windows.