See also: Soho

SoHO ( Solar and Heliospheric Observatory , is solar and heliospheric observatory) is a Space probe placed orbits about it around the Sun. Its main aim is to study the Sun. It is the fruit of a collaboration between the European space agency (ESA) and NASA.

History

It is launched since the Earth on December 2nd, 1995 since the base of Cap Canaveral, in Florida, by a rocket of the type Atlas II.

Serious problem

SoHO underwent in 1998 a serious problem, it left in rotation on itself (spin) in doubtful circumstances on June 24th, 1998.

Knowing that in the space, the room temperature is of -150 °C when one is in the shade of the Sun, and of +200°C when one is exposed there, the means of thermal regulation of a satellite are always very precise and this kind of disordered movement causes either an overheating or a very important fall of temperature according to the exposed part of the satellite. It is only one month after having lost the contact which the agencies American and European give the finger on SoHO. July 23rd, a first localization of the satellite is made thanks to the Radiotélescope of Arecibo to Puerto Rico, being used as transmitter and an antenna 70 meters in diameter of NASA like receiver radar.

August 3rd, first answer of SoHO. A first Télémétrie is received the 8 of the same month, giving a first estimate of the state of the instruments on board and means of propulsion. The tanks of Hydrazine being used for the chemical propulsion of the satellite are extremely cooled, and hydrazine is cold. It was thus necessary to thaw out it after a fashion to be able, the September 16th, to always start a phase of stabilization of the satellite moving of spin.

It is only on October 16th that NASA announced a re-starting normal of the project, the instruments too not having suffered.

End of the mission

The completion date of mission of SoHO is scheduled for December 2009. After this date, only instruments VIRGO, GOLF and LASCO will remain operational. Instrument MDI will be stopped to let the HMI of the Solar Dynamics Observatory function.

Constitution

It contains twelve instruments of observation of the Sun, for a total payload of 610 kg. Its mass with launching was of 1.850 kg. The satellite was built by the company Matra, the instruments by scientific laboratories European and the United States.

Instruments

Several scientific instruments are on board probe:

Position

The satellite is located between the Ground and the Sun, positioned in the neighborhoods of the Point of Lagrange L1, place where the terrestrial attractions and solar balance. As the point of Lagrange L1 is unstable, SoHO is forced to carry out revolutions around this one according to a curve in form of Haricot. It is roughly to 1,5 million kilometers of the Earth, in the direction of the Sun.

Current results

SoHO is famous to have revolutionized our knowledge of the Sun. Million stereotypes and measurements, scientific hundreds of publications are due to the data which it transmitted to the Earth.

A fabulous revealing comet

In addition, its position enables him to detect a great number of Comet S. It had listed 500 of them in August 2002 and 3 years later, the August 5th 2005, Toni Scarmato discovers the 1.000ème comet.

The images taken by SoHO show comets very approaching close to the Sun and the Solar wind to blow with force on them, making them undulate one of the two tails in a spectacular way. Approximately 85% of comets discovered with the assistance of the stereotypes of SoHO belong to the group of Kreutz (in the homage of Heinrich Kreutz, the first to have identified this particular group of comets). For a great part, these comets evaporate in the vicinity of the Sun.

See too

• CLUSTER

External bonds

• Official site of the SoHO probe, on the site of NASA
• last images, vidéos and given of SoHO, on the site of NASA

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