NOZOMI (PLANET-B)
NOZOMI (PLANET-B) was Japan's first Mars explorer, intended to study the interaction of the Martian upper atmosphere with the solar wind, measure magnetic fields, and remotely observe Mars and its satellites. A defective valve during its December 1998 powered Earth swing-by led to insufficient thrust and excessive propellant use, forcing a redesigned journey with further Earth encounters in 2002 and 2003. Communications and thermal-control failures prevented Mars-orbit insertion. The team diverted the spacecraft away from Mars on December 9, 2003; it returned interplanetary observations rather than the planned orbital Mars survey.
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Identity
- Aliases
- NOZOMIPLANET-BNozomi MissionPlanet-B
- Name
- NOZOMI (PLANET-B)
- Status
- completed
Details
- Astronauts
- -
- Description
- NOZOMI (PLANET-B) was Japan's first Mars explorer, intended to study the interaction of the Martian upper atmosphere with the solar wind, measure magnetic fields, and remotely observe Mars and its satellites. A defective valve during its December 1998 powered Earth swing-by led to insufficient thrust and excessive propellant use, forcing a redesigned journey with further Earth encounters in 2002 and 2003. Communications and thermal-control failures prevented Mars-orbit insertion. The team diverted the spacecraft away from Mars on December 9, 2003; it returned interplanetary observations rather than the planned orbital Mars survey.
- Destination
- Heliocentric orbit
- End Date
- 2003-12-09
- Outcome
- NOZOMI did not achieve its planned Mars orbit. Multiple problems forced major trajectory changes and delayed the Mars approach; a defective thrust valve caused insufficient thrust and excessive fuel use, while later communication and thermal-control failures made orbit insertion impossible. The team abandoned Mars insertion on December 9, 2003 to avoid an impact, but NOZOMI still returned valuable interplanetary observations, including hydrogen Lyman-alpha measurements, and remains in a heliocentric orbit around the Sun near that of Mars.
- Programs
- -
- Start Date
- 1998-07-04
- Vehicle Families
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Assets & Meta
- Creation Time
- August 15, 2026 at 22:22:09 UTC
- Updated Time
- October 29, 2026 at 15:15:56 UTC
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- Affiliations
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- Space Stations
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