For the future planetary exploration of the world ---What "NOZOMI" left with us---

"NOZOMI" carried out its observation of plasma environment surrounding the moon, taking the opportunity of its lunar swingby operation. The moon absorbs solar wind which is the plasma flow from the sun. Ion Energy Analyzer (ISA), for the first time in the world, succeeded in detecting plasma which was part of solar wind reflected by the moon. As the result of detailed investigation on the velocity of ions, the position of the moon and the flow direction of solar wind, this plasma is surely related to the moon, and is thought to be solar wind reflected by the moon rather than plasma newly generated on the moon. In the Apollo project, some rocks on the surface of the moon were said to be weakly magnetized.

Above observation by ISA onboard "NOZOMI" suggests that the shock wave on the impact of solar wind to these magnetized rocks would reflect the ions of the solar wind. In addition, as the flow of the solar wind is dammed on the near side of lunar surface, highly vacuum region with quite low plasma density is generated on the far side. Elecronic Energy Analyzer (ESA) detected electrons which came flying from the highly vacuum direction.

High Energy Particle Instrument (EIS), together with Ion Mass Imager (IMI), worked as a long term valuable monitor of observing solar wind functioned as a far distant observation station, and continued to observe solar fl

Magnetic Flux Instrument (MGF), which had been to observe the magnetic field of Mars, observed the magnetic field of solar wind in interplanetary space. Solar wind carries with it the magnetic field of the surface of the sun. The observation is very important because it was performed on the orbit far from the earth. It revealed how the magnetic field of solar wind changes with the distance from the sun and the earth.

Generally speaking, the velocity of solar wind near the sun is difficult to know. When specially dense coronal materials come out of the sun in lateral direction when viewed from the earth, however, we can observe the speed of solar wind correctly. "NOZOMI" observed such coronal materials directly in space, and could have invaluable information on the initial velocity of solar wind and on how the velocity changes as it moves in interplanetary space.

Detailed observation of the structure of solar corona was done by Radio Wave Science (OLC) using X band (8 MHz).

We are so heartbreakingly sorry to think of scientists and engineers responsible for the observation instruments, including those from overseas, never actually used in spite of the probe approaching so close to Mars. "NOZOMI" was installed with globally highest-level observation instruments for magnetic field and plasma. "NOZOMI" was supposed to supplement observation works with American and European satellites aimed at observing Mars as a solid planet. We are so deeply regretful for what destined to happen to "NOZOMI" this time.

We received continuous e-mails and telephones at the end of rescue operation of "NOZOMI" to say, "Come on! Hold on! NOZOMI". We would like to apologize from the bottom of my heart for our inability of responding to expectations of those people. We will never, never forget, for all the rest of my life, all those warm hearted supports given to us with precious 270,000 participations from every corner of this country and from all over the world as well as the death struggling efforts by "NOZOMI" mission team at the last desperate moment of December, 2003. Taking this opportunity, let us express our apology for not joining Mars rush this time. We hope that European and American missions will make wonderful coordinated success to leave great footprints on the exploration of the red planet.

(Yasunori Matogawa, Director, Office of Public Outreach and Space Education of ISAS, takes full responsibility for the wording and content of this article.)