Overview

Nozomi (PLANET-B) was developed by the Institute of Space and Astronautical Science (ISAS) as Japan’s first Mars probe.
Its main missions are to study the interaction between the Martian upper atmosphere and the solar wind, to observe the Martian magnetic field, and to perform remote sensing with a satellite on the Martian surface.

The probe is a rectangular prism weighing 540 kg and measuring 1.6 m long, 1.6 m wide and 0.58 m high, with its solar panels unfolded it will be about 6 m in size.
After arriving on Mars, four 25 m long wires would be extended to form a huge antenna measuring 52 m from tip to tip.

It was launched by the M-V Rocket No. 3 from the Kagoshima Space Center (currently the Uchinoura Space Center) on July 4, 1998, and was scheduled to arrive at Mars in October 1999. However, trouble occurred during the journey to Mars, which led to a major change in its orbit, and it finally approached Mars in December 2003, four years later than originally planned.
However, frequent problems caused the system required for insertion into Mars orbit to not function, and on December 9, 2003, the attempt to enter Mars orbit was abandoned. Nozomi is now an artificial planet that flies forever near the orbit of Mars.

DARTS archives raw telemetry data from Nozomi. However, data processing and analysis software are not archived, which may limit the ability to support scientific data analysis.

Observation Instruments

Mars Imaging Camera (MIC)

MIC is a visible light camera for taking high-resolution images of the lower atmosphere and surface of Mars. It will acquire color images with a resolution of up to 1024 x 1024 pixels.
It will be able to observe global meteorological activities in the lower atmosphere, such as cloud distribution, polar haze, dust storms, and the growth and decline of polar ice.
When it is closest to Mars, it will also be able to image the surface with a resolution of 100 m, allowing us to learn about the materials on the surface.

Magnetic Field Measurement (MGF)

MGF is a device for measuring the Martian magnetic field in three axes with a measurement precision of less than 0.1 nT, allowing it to detect minute fluctuations in the Martian magnetic field.

Probe for Electron Temperature (PET)

PET is an instrument to measure the electron temperature in the Martian atmosphere, with a measurement range from 500 K to 10,000 K, which will contribute to understanding the Martian plasma environment.

Electron Spectrum Analyzer (ESA)

ESA will measure the energy spectrum of electrons in the Martian atmosphere, from 12 eV to 15 keV, acquiring three-dimensional data at intervals of up to 8 seconds.

Ion Spectrum Analyzer (ISA)

ISA will measure the energy spectrum of ions in the Martian atmosphere, ranging from 6 eV/q to 16 keV/q, acquiring three-dimensional data at intervals of up to 8 seconds.

Electron and Ion Spectrometer (EIS)

EIS is an instrument that measures the energy spectrum of particles (electrons, protons, helium ions, and oxygen ions) with even higher energy than ESA and ISA. The measurement range for electrons is 30 keV to 350 keV, and for protons is 30 keV to 1000 keV.

Extra Ultraviolet Scanner (XUV)

XUV is an instrument to measure extreme ultraviolet light scattered by helium atoms (58.4 nm) and helium ions (30.4 nm) in the Martian atmosphere. By measuring from outside the ionosphere, the total amount and altitude distribution of helium ions/atoms in the Martian ionosphere can be obtained.

Ultraviolet Imaging Spectrometer (UVS)

UVS is an instrument for measuring ultraviolet light (115 - 310 nm) and the ratio of scattered light from deuterium to hydrogen (D/H ratio).
This will enable us to observe the hydrogen and oxygen corona around Mars and investigate the interaction between the upper Martian atmosphere and the solar wind, and by measuring the D/H ratio, we will be able to investigate the evolution and escape process of the Martian atmosphere.

Plasma Wave and Sounder (PWS)

PWS is a device that uses a 52-m-long antenna together with the LFA to observe plasma waves.
It observes plasma waves in the high-frequency range (20 kHz - 5 MHz) to investigate plasma wave phenomena around Mars that occur as a result of interactions with the solar wind, and to study the mechanisms of these interactions.
It also transmits pulsed radio waves with frequencies of 30 kHz - 6.8 MHz from the Nozomi spacecraft’s orbit above the Martian ionosphere, and captures the radio waves (echoes) that are reflected by the ionosphere and return. By examining the delay time of the echoes, it is possible to explore the plasma density distribution and dynamics in the Martian ionosphere.

Low Frequency Plasma Wave Analyzer (LFA)

LFA, together with PWS, is an instrument that uses a 52-m-long antenna to observe plasma waves.
It measures plasma waves in the low-frequency band (10 Hz - 32 kHz, VLF/ELF) to investigate the Martian magnetosphere and upper ionosphere.
This will help us understand the interaction between the Martian magnetic field and plasma.

Ion Mass Imager (IMI)

IMI is an instrument that images the mass of ions in the Martian atmosphere.
The mass range of ions measured is 1 - 10¹² a.m.u., and the energy range is from 10 eV/q to 35 keV/q, and three-dimensional data can be acquired at intervals of up to 4 seconds.
Data from IMI, ESA, ISA, and EIS provide information on the composition, energy, and velocity distribution of ions at a given point.

Mars Dust Counter (MDC)

MDC is a device that measures the mass and velocity of dust particles around Mars. It can observe the range of 10^-10 to 10^-5 g for dust particles moving at 1 km/s, and 10^-18 to 10^-13 g for dust particles moving at 100 km/s.
It is predicted that there is a ring-shaped region around the orbit of Phobos, a moon of Mars, and a torus-shaped region around Deimos, a moon of Mars, where dust particles are distributed. MDC will measure the dust particles and clarify their distribution.

While NOZOMI is traveling from Earth to Mars, it will also observe dust supplied by asteroids and comets, and dust coming from outside the solar system.

Neutral Mass Spectrometer (NMS)

NMS is an instrument that measures the mass of neutral gases in the Martian atmosphere with a measurement range of 1 to 60 Daltons and a mass resolution of 8.

Thermal Plasma Analyzer (TPA)

TPA is an instrument that measures the drift velocity of thermal plasma in the Martian atmosphere in the range of 0.1 eV to 100 eV, contributing to a detailed understanding of the Martian plasma environment.

Achievements

Although Nozomi failed to enter Mars orbit, the data obtained during the process provided valuable lessons regarding the technical challenges of Mars exploration and the operation of space probes.