Suisei (PLANET-A)
Suisei (PLANET-A) — ISAS's probe to Halley's Comet, launched on 18 August 1985 (UTC). From November 1985 its ultraviolet camera photographed the comet's cloud of hydrogen, about 20 million km across, and on 8 March 1986 it passed 151,000 km from the nucleus (152,400 km in NASA's history). Its images gave the comet's rotation period and showed its release of water rising and falling. It was struck by at least two dust particles. Its propellant ran out in 1991, and a last Earth swing-by in August 1992 completed its mission. (Its position here is representative.)
Key facts
Mission & specifications
Mission
- Operator
- ISAS (Japan)
- Launched
- August 18, 1985
- Status
- Completed
Trajectory
- Distance from the Sun
- 0.997 AU
- Computed from the cached position
- Distance from Earth
- 5,224,457 km
- Computed from cached positions
- Distance from Venus
- 0.296 AU
- Computed from cached positions
Mission
Suisei, "Comet", known before launch as PLANET-A, was ISAS's probe to Halley's Comet: a 139.5 kg craft launched on an M-3SII rocket from Uchinoura on 18 August 1985 at 23:33 UTC (19 August in Japan), seven months after its twin Sakigake. From November 1985 its ultraviolet camera took up to six images a day of the comet's cloud of hydrogen, about 20 million km across. On 8 March 1986 it passed 151,000 km from the nucleus (152,400 km in NASA's history Beyond Earth). Its images gave the comet's rotation period and showed its release of water rising and falling, and it was struck by at least two dust particles. In April 1987 it was steered to return to Earth. Its hydrazine ran out on 22 February 1991, and on 20 August 1992 it passed Earth, completing its mission; planned encounters with comets Giacobini–Zinner and Tempel–Tuttle in 1998 were cancelled. No date of its last contact has been published.
- 1985Suisei launches toward Halley's Comet on an M-3SII rocketLaunch
From the nucleus: NSSDCA's figure and that in NASA's history Beyond Earth.
Images
No openly licensed image of Suisei has been found.