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Planet-B is Nozomi is Hope:
Hope Went Astray On The Way To Mars
Japan's Hope was its first interplanetary probe. Japan, the fourth nation ever to send a satellite to Earth orbit, became the third nation ever to send a spacecraft to Mars when it blasted off a probe then called Planet-B from Japan's Kagoshima Space Center on the southern island of Kyushu on July 4, 1998.
Japan's Nozomi orbiting over the Red Planet
ISAS artist conception
While on its way to Mars, Planet-B was renamed Nozomi which means Hope. It did arrive in the vicinity of Mars in December 2003, but ground controllers back on Earth were unable to direct it into orbit around the Red Planet. It flew on by and was lost in a useless orbit around the Sun.
Here's what went wrong along the way to Mars:
A bumpy road. Unfortunately, an out-of-control thruster necessitated an heroic rescue effort, which lead Nozomi around the Sun on its way to the Red Planet. That meant arrival at Mars would be four years later than originally planned.
In addition, Nozomi suffered a further setback in 2002 when one of its communication systems was knocked out by a massive outburst of energy from the Sun on April 21.
Then, as it approached Mars five years behind schedule and low on fuel, the spacecraft's heating system broke down and had to be brought back to life to prevent its fuel from freezing up. As Nozomi moved away from the Sun, it cooled to a point where its fuel could freeze. That left the probe unable to fire its thrusters to slow down and drop into orbit around Mars.
At that point, spaceflight experts gave the robot probe only a 50 percent chance of entering Mars orbit successfully and carrying out its assignment.
The flight plan. The $88 million (11 billion yen) Nozomi was launched from a pad in the southwestern prefecture (state) of Kagoshima on July 4, 1998, to probe the atmospheric movements and topography of Mars, as well as measure solar winds.
After launch in 1998, the robot science explorer went into a looping orbit around Earth, which took it out and around the Moon. Nozomi completed two swings by the Moon to establish its final trajectory to Mars. The swing-by technique helped the probe gather speed for the trip to Mars.
Nozomi originally was to have arrived at the Red Planet at the end of 1999.
Once the spacecraft reached Mars, it was to have been placed in a highly elliptical or "egg-shaped" orbit stretching from a low of 93-186 miles out to about 17,000 miles above the planet's surface.
What went wrong? Nozomi made a first gravity-assist flyby of the planet Earth on September 24, 1998. Following a second Earth flyby on December 18, 1998, a thruster on the spacecraft stuck open and much fuel was wasted. Nozomi did not receive sufficient acceleration boost to reach orbit around Mars.
Controllers at Japan's Institute of Space and Astronautical Sciences (ISAS) ordered the thrusters to burn in a correctional manuever on Dec. 21, 1998. However, that did not leave enough fuel for Nozomi to be able to slow itself down later as it entered Mars orbit.
The situation looked bleak and called for an extraordinary effort to save Nozomi.
How they fixed it. Ground controllers in Japan radioed orders to the spacecraft, assigning it a new flight plan.
Now it would make three trips around the Sun and two additional Earth flybys. They hoped those gravity assists from the Sun and Earth would give Nozomi just the right speed for entering Mars orbit by 2004, without requiring much thruster fuel.
If it had worked, Nozomi's new orbital path around Mars would have been elliptical, ranging from a low of 93 miles out to a high of 31,620 miles.
ISAS researchers said they believed the spacecraft's science instruments would work properly after the four year delay. A benefit of the longer flight, they said, would be extra time to collect and send back data on the solar wind in interplanetary space.
Then the radio went down. Nozomi suffered a setback in 2002 when one of its communication systems was knocked out by a massive outburst of energy from the Sun on April 21.
Such powerful solar flares are well known on Earth where they sometimes cause radio and electrical disruptions.
Japan's Education Ministry, which oversaw the program, expected it would take six months to fix the communication problem. Fortunately, the probe's computer controls were not damaged so engineers on Earth were able to repair the spacecraft by remote control. The probe was able to continue on a course that would take it to Mars by 2004.
The probe completed speed-boosting flybys of Earth in December 2002 and June 2003.
Unfortunately, there was insufficient fuel left when the spacecraft reached Mars. Controllers in Japan could not direct it into an orbit around Mars. Nozomi flew on by into a useless orbit around the Sun.
Nozomi was designed to perform long-term studies of the upper Martian atmosphere and ionosphere, and its interaction with the solar wind.
Nozomi's Martian Studies
The low-altitude portion of the orbit would have been used for remote sensing of the lower atmosphere and surface, and for direct measurements of upper atmosphere and ionosphere.
The more distant parts of the orbit around Mars would have allowed instruments to probe the ions and neutral gas escaping from the Red Planet, which interact with the charged-particle "wind" blowing outward from the Sun. Ionization of the upper atmospheric gas by solar radiation produces the charged-particle atmosphere (ionosphere) that acts as an obstacle to the solar wind.
This radiation produces species of gas not seen in Mars' lower atmosphere, such as nitric oxide, or dissociates the atmosphere into single atomic species, such as atomic oxygen. If these neutral or ionized species possess enough energy, they can escape the gravitational pull of Mars, resulting in a net atmospheric loss. Measurements of lighter species such as atomic hydrogen and deuterium also can provide clues about the evolution of the Martian atmosphere.
More like Venus. Mars has little or no intrinsic magnetic field to interact with this process, making it more like Venus in this respect than Earth.
The upper atmosphere of Venus and its solar wind environment had been studied for almost fourteen years by the U. S. Pioneer Venus Orbiter spacecraft from a similar, highly elliptical orbit. Nozomi carried an insturment, known as NMS, which was a state-of-the-art enhancement of the Pioneer Venus mass spectrometer. It weighed only six pounds. To conserve space and weight, electronic items such as transistors and integrated circuits were removed from their outer casings and placed in larger packages called hybrid circuits.
Dust storms. Data from previous Mars exploration spacecraft such as Mariner 9 indicate that dust storms near the surface can heat the lower atmosphere and increase the gas density in the upper atmosphere where Nozomi would have made its measurements. Meanwhile, the U.S. Mars Climate Orbiter carries an instrument called the Pressure Modulated Infrared Radiometer, which will provide complementary information on the lower atmosphere and its response to dust storms.
The main objective was to investigate the motion and structure of the upper atmosphere of the planet Mars. To do that, 14 instruments were on board the spacecraft. The observations by Nozomi would have included:
None of these instruments now will benefit Mars scientists.
- Magnetic field of Mars
Scientists are not sure if Mars has a magnetic field or not. Nozomi would have measured precisely the Martian magnetic field.
- Atmosphere of Mars
Nozomi would have investigated the composition and structure of the atmosphere with ultraviolet remote-sensing detectors. A small mass-analyzer would have been used to study the composition of the the ionosphere.
- Plasma in the Ionosphere of Mars
Nozomi would have studied the components, structure, temperature and plasma waves within the ionosphere with detectors.
- Pictures of Mars and its Moons
A small camera would have snapped pictures of Martian weather and its two moons -- Phobos and Deimos. Those images would have helped scientists understand how sandstorms and clouds are generated on Mars and the planet's polar icecaps grow and decay.
- Dust Rings around Mars
Scientists suggest there may be a dust-ring along the orbit of Phobos. By using the dust counter aboard Nozomi, they may have been able to discover if it exists.
Nozomi carried 14 instruments for scientific research at Mars. Those science packages of equipment were supplied by:
Spectrometer. One of the instruments from the United States was the Neutral Mass Spectrometer and Ultra Stable Oscillator (NMS) provided by NASA to measure the gas composition of the upper atmosphere of Mars.
- United States, NASA and Johns Hopkins University
- Canada, Calgary University
- Germany, Munich Technical University
- France, space agency CNES
The Neutral Mass Spectrometer would have enabled researchers to measure the chemical composition of the upper atmosphere of Mars on a global scale, which had not been done before.
Previous upper atmospheric composition measurements were done in only two locations as NASA's Viking landers entered the Martian atmosphere on July 20 and Sept. 3, 1976.
Precise clock. Another U.S. instrument package was a radio science experiment. That hardware was built for NASA by the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. The ultra-precise signals generated by the oscillator would have served as a very accurate clock to enable analysis of the Martian atmosphere and might have helped guide the spacecraft in its orbit around the Red Planet.
The spacecraft was built by the Nippon Electric Corporation and was launched on one of Japan's M-5 rockets – a launcher that had been designed to expand Japan's launch capability to the inner planets and beyond.
The Nozomi project was managed by ISAS and the Japanese Ministry of Education. ISAS personnel operated the spacecraft and its instruments. Flight operations were conducted from Sagamihara Spacecraft Operations Center.
Information on NMS and the NASA portion of the Nozomi mission is at the Laboratory for Atmospheres at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Japan launched its Planet-B interplanetary probe on July 3, 1998 UTC to look for signs of water on Mars and measure the Red Planet's magnetic field.
In space, it was renamed Nozomi, which is Japanese for Hope.
The spacecraft was Japan's first interplanetary mission. Previously, only the United States and Russia had sent spacecraft to Mars.
While orbiting Earth for four months, Nozomi made two trips around the Moon to establish its trajectory to Mars. The probe made its first lunar swing-by on September 24, 1998. Then it made a second lunar swing-by on December 18, 1998.
After that, it executed an Earth swing-by two days later to send Nozomi on to Mars.
Unfortunately, a thruster valve malfunctioned during the Earth swing-by and the flight control team on Earth had to send a command to get it back on the road to Mars. That left Nozomi without enough fuel to get to Mars on schedule.
The ground controllers had to find an alternative trajectory that could be accomplished with low fuel. It required two additional Earth swing-bys in December 2002 and June 2003.
Nozomi originally was to have arrived at Mars on October 11, 1999. The new arrival time became January 2004. ANOTHER STORY ABOUT JAPAN'S NOZOMI
At Mars. Nozomi will drop into an elliptical or egg-shaped orbit ranging from a low of 93-186 miles above the planet to a high of 17,000 miles above the surface. From there, it will study the upper atmosphere and its interaction with the solar wind.
Science Instruments. The probe carried fourteen instruments designed by specialists in Japan, Germany, Canada, Sweden and the United States to study the Martian interior, surface and atmosphere. The plan is for the probe to spend one Martian year -- the equivalent of two Earth years -- studying Mars and its two moons. It will collect evidence about whether life could have have existed on Mars -- particularly if water is hidden under the planet surface. Planet-B will perform long-term studies of the upper Martian atmosphere and ionosphere, and its interaction with the solar wind.
Planet-B will arrive in orbit around Mars in October 1999. Its science instruments will begin sending back information on the Red Planet's magnetic field while looking for so-called water signature signs of water on or below the surface. Features seen on the planet surface suggest to scientists that water existed on Mars in the past. The question is what happened to the water? Did it evaporate into space? Is still on the planet, but not in liquid form? Could it be under the surface?
NASA is the U.S. space agency. Among the fourteen the instruments aboard Planet-B was the Neutral Mass Spectrometer (NMS), a NASA tool designed to measure the gas composition of the upper atmosphere of Mars. NASA also supplied the Ultra Stable Oscillator, a radio science experiment.
Spectrometer. The Neutral Mass Spectrometer enables researchers to measure the chemical composition of the upper atmosphere of Mars on a global scale. That has not been done before. Previous upper atmosphere composition measurements were done in only two locations -- as NASA's Viking landers entered the Martian atmosphere on July 20, 1976, and September 3, 1976.
The radio science hardware generates ultra-precise signals. The oscillator serves as a very accurate clock to enable analysis of the Martian atmosphere and to help guide the spacecraft as it orbits the Red Planet.
When Planet-B is in the low-altitude portion of its orbit, the spectrometer will be used for remote sensing of the lower atmosphere and surface, and for direct measurements of upper atmosphere and ionosphere.
When Planet-B is in the more distant parts of the orbit, the spectrometer will probe the ions and neutral gas escaping from Mars, which interact with the charged-particle "wind" blowing outward from the Sun.
Ionosphere. Ionization of the planet's upper atmospheric gas by solar radiation produces the charged-particle atmosphere -- the ionosphere -- that acts as an obstacle to the solar wind. This radiation produces gas not seen in Mars' lower atmosphere, such as nitric oxide, or dissociates the atmosphere into single atomic species, such as atomic oxygen. If these neutral or ionized species possess enough energy, they can escape the gravitational pull of Mars, resulting in loss of atmosphere. Measurements of lighter species, such as atomic hydrogen and deuterium, also can provide clues about the evolution of the Martian atmosphere.
Mars has little or no intrinsic magnetic field to interact with this process, making it more like Venus in this respect than Earth. The upper atmosphere of Venus and its solar windenvironment were studied for fourteen years by the U. S. spacecraft Pioneer Venus Orbiter from a similar, highly elliptical orbit. The Planet-B Neutral Mass Spectrometer is a state-of-the-art enhancement of the Pioneer Venus mass spectrometer, weighing only six pounds. To conserve space and weight, electronic items such as transistors and integrated circuits were removed from their outer casings and placed in larger packages called hybridcircuits.
Data from previous Mars exploration spacecraft, such as Mariner 9, indicate that dust storms near the surface can heat the lower atmosphere and increase the gas density in the upperatmosphere where Planet-B will make its measurements. The U.S. Mars Surveyor 1998 mission -- known as the Mars Climate Orbiter to be launched in December 1998 -- carries an instrument called the Pressure Modulated Infrared Radiometer, which will providecomplementary information on the lower atmosphere and its response to dust storms.
ISAS. Planet-B was built by the Nippon Electric Corporation. The Planet-B project is managed by the Institute of Space and Astronautical Science (ISAS) within the Japanese Ministry of Education. ISAS personnel operate the spacecraft and its instruments. The M-5 rocket is designed to give Japan the ability to launch probes to the inner planets of the Solar System and beyond.
The radio science hardware was built by the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. The Neutral Mass Spectrometer was supplied by NASA's Goddard Space Flight Center Laboratory for Atmospheres at Greenbelt, Maryland.
- Another story about Japan's Nozomi
- NASA's part of Planet-B with graphics
- National Space Development Agency of Japan
- Exploring Mars
- Mars, the Red Planet National Air and Space Museum
- Mars Watch
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