Yinghuo-1

Yinghuo-1 was a Chinese Mars-exploration space probe, intended to be the first Chinese spacecraft to explore Mars. It was launched from Baikonur Cosmodrome, Kazakhstan, on 8 November 2011, along with the Russian Fobos-Grunt sample return spacecraft, which was intended to visit Mars' moon Phobos.^[1][5] The 115-kg (250-lb) Yinghuo-1 probe was intended to orbit Mars for around two years,^[4] studying the planet's surface, atmosphere, ionosphere and magnetic field.^[6] Shortly after launch, Fobos-Grunt was expected to perform two burns to depart Earth orbit bound for Mars. However, these burns did not take place, leaving the probe stranded in orbit.^[7] On 17 November 2011, Chinese state media reported that the probe had been declared lost by the CNSA.^[8] Yinghuo-1 and Fobos-Grunt are likely to undergo destructive re-entry in January 2012.^[9]

Name

Yinghuo-1's name (simplified Chinese: 萤火; traditional Chinese: 螢火; pinyin: yínghuǒ – firefly, literally "luminous fire") was a tribute to the near-homophone yinghuo (simplified Chinese: 荧惑; traditional Chinese: 熒惑; pinyin: yínghuò). This word, a short form of "shimmering planet" (熒惑星), is an ancient Chinese name for Mars.

Background

On 26 March 2007, the director of the China National Space Administration, Sun Laiyan, and the head of the Russian Space Agency, Anatoly Perminov, signed a landmark space co-operation accord, entitled the "Cooperative Agreement between the China National Space Administration and the Russian Space Agency on joint Chinese-Russian exploration of Mars". One stipulation of the agreement was the construction and launch of the Yinghuo probe and its Russian counterpart, Fobos-Grunt.^[3]

Instruments and objectives

Yinghuo-1's primary scientific objectives were:

1. To conduct detailed investigation of the plasma environment and magnetic field;
2. To study Martian ion escape processes and their possible mechanisms;
3. To conduct ionosphere occultation measurements between Yinghuo-1 and Fobos-Grunt, focusing on the sub-solar and midnight regions;
4. To observe sandstorms on the Martian surface.

The probe's scientific payload consisted of a four primary instrument packages:^[10][11]

1. A plasma package, consisting of an electron analyzer, ion analyzer and mass spectrometer;
2. A fluxgate magnetometer;
3. A radio-occultation sounder;
4. An optical imaging system, consisting of two cameras with 200m resolution, allowing high-quality images of the Martian surface to be captured from orbit.

Mission profile

Following its transit to Mars, Yinghuo-1 was planned to separate from Fobos-Grunt in October 2012^[12] and enter a 72.8-hour equatorial Martian orbit,^[4] with an orbital inclination of approximately 5 degrees. Fobos-Grunt and Yinghuo-1 would have conducted Mars ionosphere occultation experiments together,^[13] although Fobos-Grunt's primary objective was to obtain surface samples from the Martian moon Phobos. Yinghuo-1 would have experienced periods of up to 8.8 hours in darkness when its orbit carried it over Mars' nightside; it would have run on reserve power during these periods, as its solar panels would have been unusable without direct sunlight.^[4]

Launch processing

On 17 October 2011, the completed Yinghuo-1 satellite arrived at Baikonur Cosmodrome with Fobos-Grunt, beginning payload processing operations in preparation for its November launch.^[14]

Launch and orbital burn failure

China's Yinghuo-1 and the Russian Fobos-Grunt spacecraft were launched together aboard a Ukrainian Zenit rocket with a Fregat upper stage from Baikonur Cosmodrome, Kazakhstan, on 8 November 2011.^[1][12] Shortly after launch, Fobos-Grunt was expected to perform two burns to depart Earth orbit and begin its journey to Mars. However, these burns did not take place, stranding the two spacecraft in their parking orbit.^[7] Despite repeated efforts to contact Fobos-Grunt and rectify the problem, the spacecraft continued to lose altitude, risking deorbit if the malfunctioning engines could not be restarted.^[15] On 17 November, Chinese state media formally declared the probe lost.^[8]

Specifications

• Length: 0.75 metres (2.5 ft) (excluding solar panels).^[16]
• Width: 0.75 metres (2.5 ft).^[16]
• Height: 0.6 metres (2.0 ft).^[16]
• Mass: 115 kilograms (250 lb).^[13]
• Power: 3-axis stabilised, 2×3 section solar array with a full-extended length of 5.6 metres (18 ft), providing average power of 90 W, and peak power of 180 W.^[13]
• HGA: 950 mm antenna dish (S-band) with a 12 W transmitter in two frequencies (8.4 and 7.17 GHz) and a data rate between 8 bps and 16 kbps.^[13]
• LGA: 80 bit/s data rate.^[13]

See also

• China National Space Agency
• Chinese Lunar Exploration Program
• Exploration of Mars
• Robotic spacecraft
• Roscosmos

References

External links

• Fobos-Grunt at Spacefiles.com. Includes an image of Yinghuo-1.