posted 04-15-2015 08:07 PM               

Space Cover 312: If At First You Don't Succeed: The Remarkable Journey Of Japan's First Attempted Mars Mission

NOZOMI (Japanese for "Wish"), known before launch as Planet-B, was launched on July 4, 1998 with a plan to orbit Mars on October 11, 1999. It had a very aggressive list of plans to accomplish after first attaining orbit of Mars. Instruments on the spacecraft were to measure the structure, composition and dynamics of the ionosphere, and study the effects of the solar wind, the escape of atmospheric constituents, the intrinsic magnetic field, the penetration of the solar-wind magnetic field, the structure of the magnetosphere, and dust in the upper atmosphere while in orbit around Mars. The mission would have also returned images of Mars' surface.

NOZOMI performed a lunar swing-by twice on August 24, 1998 and December 18, 1998 to increase the apogee of its orbit. On December 20, 1998, it performed a powered swing-by of Earth but due to a defective thrust valve, it had insufficient thrust. Fuel consumption was excessive as a consequence of the change in flight course, and it became impossible to insert the spacecraft into orbit around Mars on the revised date of January 5, 2004.

On April 21, 2002 as Nozomi was approaching Earth for its first gravity assist maneuver, powerful solar flares damaged the spacecraft's onboard communications and power systems. An electrical short occurred in a power cell used to control the attitude control heating system, allowing the hydrazine to freeze. The fuel thawed out as the craft approached Earth and maneuvers to put the craft on the correct trajectory for its Earth flyby were successful.

NOZOMI performed the Earth swing-by twice more in December 2002 and June 19, 2003 to enter the orbit toward Mars. However, on December 9, 2003, efforts to orient the craft to prepare it for a December 14, 2003 orbital insertion burn failed, and efforts to save the mission were abandoned. The small thrusters were fired on December 9, moving the closest approach distance to 600 miles so that the probe would not inadvertently impact on Mars and possibly contaminate the planet with Earth bacteria, since the orbiter had not been intended to land and was therefore not properly sterilized.

The spacecraft flew by Mars on December 14, 2003 and went into a roughly 2-year heliocentric orbit 5 years, 5 months and 10 days after launch. It is now going to fly forever in orbit around the Sun near the orbit of Mars. However, NOZOMI did provide some valuable data by conducting a variety of observations such as measurement of hydrogen Lyman-alpha light in interplanetary space.

This launch cover was difficult to come by, but after several attempts I found a Japanese collector who agreed to obtain this cover for me. If anyone else has one, I'd be interested in seeing another as I have no idea as to how many were created. The cachet pictures the planned mission course.

(The bird on the stamp is a Japanese White Eye which can also be found in Hawaii.)