Launch Date July 3, 1998
Launch Site Tanegashima Space Center, Tanegashima, Japan
Destination Mars
Type Orbiter
Status Unsuccessful
Nation Japan
Alternate Names 1998-041A, Planet-B, 25383


Japan's Nozomi was designed to study Mars' upper atmosphere and its interaction with the solar wind from orbit and study the planet's magnetic field. It carried cameras to photograph the Martian surface and the planet's two moons. Japanese engineers also planned the mission as a technology test for future deep space missions.


During five years in space Nozomi did send back data on interplanetary space, but it could not complete its mission. A series of mishaps and malfunctions made it impossible for the spacecraft to enter Mars orbit. The spacecraft eventually ran out of fuel and was sent into orbit around our Sun to avoid a collision with Mars.

Key Dates

July 3, 1998: Launch

Oct. 11, 1999: Mars Orbit Insertion (Unsuccessful)

Dec. 14, 2003: Second Attempt, Mars Orbit Insertion (Unsuccessful)

In Depth

Nozomi, Japan's fourth deep space probe, was also its first planetary spacecraft. The spacecraft was originally slated to enter a highly elliptical orbit around Mars on Oct. 11, 1999.

Its mission was to conduct long-term investigations of the planet's upper atmosphere and its interactions with the solar wind and to track the escape trajectories of oxygen molecules from Mars' thin atmosphere. The spacecraft also was to take pictures of the planet and its moons from its operational orbit of 300 x 47,500 kilometers. During perigee, Nozomi was to perform remote sensing of the atmosphere and surface; while close to apogee, the spacecraft would have studied ions and neutral gas escaping from the planet.

Although designed and built by Japan, the spacecraft carried a set of fourteen instruments from Japan, Canada, Germany, Sweden and the United States.

After entering an elliptical parking orbit around Earth, Nozomi was sent on an interplanetary trajectory that involved two gravity-assist flybys of the Moon on Sept. 24 and Dec. 18, 1998 (at 2,809 kilometers), and one of Earth on 20 Dec. 20, 1998 at 1,003 kilometers.

Due to insufficient velocity imparted during the Earth flyby and two trajectory correction burns on Dec. 21, 1998 that used more propellant than intended, Nozomi's originally planned mission had to be completely reconfigured.

A redesigned mission plan called for Nozomi to arrive in Mars orbit in December 2003, four years after its original schedule. But the spacecraft—damaged by solar flares and out of fuel - was ultimately diverted to avoid a possible collision with Mars. The Japanese Aerospace Exploration Agency declared the mission lost on Dec. 9, 2003.


Launch Vehicle: M-5 (No. 3)

Spacecraft Mass: 540 kg at launch (orbiter was 258 kg)

Spacecraft Instruments:

  1. MIC visible camera

  2. MGF magnetometer

  3. ESA energetic electrons experiment

  4. ISA energetic ions experiment

  5. IMI energetic ion mass experiment

  6. EIS high-energy particles experiment

  7. TPA thermal ion drift experiment

  8. PET electro, UVS ultraviolet spectrometer

  9. PWS sounder/HF waves experiment

  10. LFA plasma waves experiment

  11. NMS neutral gas mass spectrometer

  12. MDC dust counter

  13. XUV EUV spectrometer

  14. USO ultra-stable oscillator/radio science experiment

Additional Resources

Japan Institute of Space and Astronautical Science: Nozomi

National Space Science Data Center Master Catalog: Nozomi

Selected References

Siddiqi, Asif A. Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, NASA, 2002.

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