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 Artist's concept ofNozomi orbiter at Mars | |
| Names | PLANET-B |
|---|---|
| Mission type | Mars orbiter |
| Operator | JAXA |
| COSPAR ID | 1998-041A |
| SATCATno. | 25383 |
| Website | isas.jaxa.jp |
| Mission duration | 5 years, 5 months and 6 days |
| Spacecraft properties | |
| Manufacturer | ISAS |
| Launch mass | 540 kg (1,190 lb)[1] |
| Dry mass | 225 kg (496 lb) |
| Payload mass | 33 kg (73 lb)[1] |
| Dimensions | 1.6 × 1.6 × 0.58 m (5.2 × 5.2 × 1.9 ft)[1] |
| Start of mission | |
| Launch date | July 3, 1998, 18:12:00 UTC |
| Rocket | M-V |
| Launch site | Uchinoura Space Center |
| End of mission | |
| Disposal | Decommissioned |
| Deactivated | December 31, 2003 |
| Last contact | December 9, 2003 |
| Orbital parameters | |
| Reference system | Heliocentric |
| Transponders | |
| Frequency | X-band: 8410.93MHz S-band: 2293.89 MHz |
PLANET series | |
Nozomi (Japanese:のぞみ; lit. "Wish" or "Hope", and known before launch asPlanet-B) was a JapaneseMars orbiter that failed to reach Mars due to electrical failure. It was constructed by theInstitute of Space and Astronautical Science,University of Tokyo and launched on July 4, 1998, at 03:12JST (July 3, 1998, at 18:12UTC) with an on-orbit dry mass of 258kg and 282 kg of propellant.[citation needed] The Nozomi mission was terminated on December 31, 2003.[citation needed]
Nozomi was designed to study the upperMartian atmosphere and its interaction with thesolar wind and to develop technologies for use in future planetary missions. Specifically, instruments on the spacecraft were to measure the structure, composition and dynamics of theionosphere, aeronomy effects of the solar wind, the escape of atmospheric constituents, the intrinsicmagnetic field, the penetration of the solar-wind magnetic field, the structure of themagnetosphere, and dust in the upper atmosphere and in orbit around Mars. The mission would have also returned images of Mars's surface.[citation needed]
After launch on the thirdM-V launch vehicle,Nozomi was put into an elliptical geocentricparking orbit with aperigee of 340 km and anapogee of 400,000 km.[citation needed]
The spacecraft used alunar swingby on September 24, 1998, and another on December 18, 1998, to increase the apogee of its orbit.[2]
It flew by Earth on December 20, 1998, at a perigee of about 1000 km. Thegravitational assist from the flyby coupled with a 7minute burn of thebipropellant rocket putNozomi into an escape trajectory towards Mars. It was scheduled to arrive at Mars on October 11, 1999, at 7:45:14 UT, but a malfunctioning valve during the Earth swingby resulted in a loss of fuel and left the spacecraft with insufficient acceleration to reach its planned trajectory. Two course correction burns on December 21 used more propellant than planned, leaving the spacecraft short of fuel.[2]
The new plan was forNozomi to remain in heliocentric orbit for an additional four years, including two Earth flybys in December 2002 and June 2003, and encounter Mars at a slower relative velocity in December 2003, or January 1, 2004.[2]
On April 21, 2002, asNozomi was approaching Earth for the gravity assist maneuver, powerfulsolar 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 thehydrazine fuel 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.[citation needed]
Another Earth flyby within 11,000 km occurred on June 19, 2003. The fuel had completely thawed out for this maneuver because of the spacecraft's proximity to theSun. However, on December 9, 2003, efforts to orient the craft to prepare it for a December 14, 2003, main thruster orbital insertion burn failed[clarification needed], and efforts to save the mission were abandoned. The small thrusters were fired on December 9, moving the closest approach distance to 1,000 km 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.[citation needed]
The spacecraft flew by Mars on December 14, 2003, and went into a roughly 2-year heliocentric orbit.[citation needed]
Nozomi was to be inserted into a highly eccentric Mars orbit with aperiareion 300 km above the surface, an apoareion of 15 Mars radii, and aninclination of 170degrees with respect to theecliptic plane. Shortly after insertion, the mast and antennas were to be deployed. The periareion would have been lowered to 150 km, the orbital period to about 38.5 hours. The spacecraft was to be spin stabilized at 7.5rpm with its spin axis (and the dish antenna) pointed towards Earth. The periapsis portion of the orbit would have allowed in-situ measurements of thethermosphere and lowerexosphere andremote sensing of the lower atmosphere and surface. The more distant parts of the orbit would be for study of theions and neutralgas escaping from Mars and their interactions with the solar wind. The nominal mission was planned for one Martian year (approximately two Earth years). An extended mission might have allowed operation of the mission for three to five years. The spacecraft was also to point its cameras at the MartianmoonsPhobos andDeimos.[citation needed]
TheNozomi orbiter was a 0.58 meter high, 1.6 meter squareprism with truncated corners. Extending out from two opposite sides were solar panel wings containingsiliconsolar cells which provide power to the spacecraft directly or viaNiMH (nickel metal hydride) batteries. On the top surface was a dish antenna, and a propulsion unit protrudes from the bottom. A 5 m deployable mast and a 1 m boom extended from the sides, along with two pairs of thin wire antennas which measure 50 m tip to tip. Other instruments were also arranged along the sides of the spacecraft. Spacecraft communications were via X-band at 8410.93MHz and S-band at 2293.89 MHz.
The 14 instruments carried onNozomi were an imaging camera, neutral mass spectrometer, dust counter, thermal plasma analyzer,magnetometer, electron and ion spectrum analyzers, ion mass spectrograph, high energy particles experiment, VUV imaging spectrometer, sounder and plasma wave detector, LF wave analyzer, electron temperature probe, and a UV scanner. The total mass budgeted for the science instruments was 33 kg. Radio science experiments were also possible using the existing radio equipment and an ultrastable oscillator.[citation needed]
The total mass ofNozomi at launch, including 282 kg of propellant, was 540 kg.[2]
Canada provided a $5 million thermal plasma analyzer.[3] This was theCanadian Space Agency's first participation in an interplanetary mission.[4] (Previously, theNational Research Council of Canada provided the High Flux Telescope (HFT) for theUlysses interplanetary mission.[5])
The spacecraft carried 14 scientific instruments to conduct scientific observations of Mars. They were[6][7][8]
Nozomi transmitted useful data on measurement ofLyman-alpha light during the course of conducting various scientific observations ininterplanetary space.[6]
The failure of Nozomi represents a $5-million loss for Canada.
The Herzberg Institute of Astrophysics (HIA) of the National Research Council of Canada provided instrumentation and test equipment for the COsmic ray and Solar Particle INvestigation (COSPIN) on the Ulysses spacecraft. The COSPIN instrument consists of five sensors which measure energetic nucleons and electrons over a wide range of energies. This was the first participation by Canada in a deep-space interplanetary mission.
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