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Sakigake (さきがけ, lit. 'pioneer', 'pathfinder'), known before launch as MS-T5, was Japan's first interplanetary spacecraft, and the first deep space probe to be launched by any country other than the USA or the Soviet Union. It aimed to demonstrate the performance of the new launch vehicle, test its ability to escape from Earth gravity, and observe the interplanetary medium and magnetic field. Sakigake was also supposed to act as a frame of reference for data received from probes that flew closer to Halley's Comet. Early measurements would be used to improve the mission of the Suisei probe launched several months later.
 Artist's rendering of the Sakigake spacecraft | |
| Mission type | Halley flyby |
|---|---|
| Operator | ISAS |
| COSPAR ID | 1985-001A |
| SATCAT no. | 15464 |
| Mission duration | 14 years and 1 day |
| Spacecraft properties | |
| Launch mass | 138.1 kilograms (304 lb)[1] |
| Start of mission | |
| Launch date | January 7, 1985, 19:27 UTC |
| Rocket | Mu-3SII |
| Launch site | Kagoshima |
| End of mission | |
| Last contact | Data: November 15, 1995 Beacon: January 8, 1999 |
| Orbital parameters | |
| Reference system | Heliocentric |
| Perihelion altitude | 0.92 AU |
| Aphelion altitude | 1.15 AU |
| Inclination | 0.07 degrees |
| Period | 382.8 days |
| Flyby of 1P/Halley | |
| Closest approach | March 11, 1986, 04:18 UTC |
| Distance | 6,990,000 kilometres (4,340,000 mi) |
Sakigake was developed by the Institute of Space and Astronautical Science for the National Space Development Agency (both of which are now part of the Japanese Aerospace Exploration Agency, or JAXA). It became a part of the Halley Armada together with Suisei, the Soviet Vega probes, the ESA Giotto and the NASA International Cometary Explorer, to explore Halley's Comet during its 1986 sojourn through the inner Solar System.
Design
editUnlike its twin Suisei, it carried no imaging instruments in its instrument payload.
Launch
editSakigake was launched January 7, 1985, from Kagoshima Space Center by M-3SII launch vehicle on M-3SII-1 mission.
Halley encounter
editIt carried out a flyby of Halley's Comet on March 11, 1986 at a distance of 6.99 million km.
Giacobini-Zinner encounter
editThere were plans for the spacecraft to go on to an encounter with 21P/Giacobini-Zinner in 1998 but the flyby had to be abandoned due to lack of propellant.
End of mission
editTelemetry contact was lost on November 15, 1995, though a beacon signal continued to be received until January 7, 1999.[2][3]
References
edit- ^ "Sakigake" (PDF). NASA. Retrieved December 2, 2022.
- ^ "Sakigake - Japan ISAS Halley's Comet Mission Sakigake". Space.about.com. Archived from the original on March 3, 2016. Retrieved February 1, 2010.
- ^ "Sakigake – NASA Master Catalog". Nssdc.gsfc.nasa.gov. Retrieved February 1, 2010.
External links
edit- Sakigake
- Sakigake Mission Profile by NASA's Solar System Exploration
- Halley's Comet Flyby
- Sakigake Mission Comet Halley Data Archive at the NASA Planetary Data System, Small Bodies Node