Displaying items by tag: SOHO spacecraft

SOHO is an ESA/NASA collaborative mission within ESA's `Solar Terrestrial Science Program' (STSP), and it is also part of ISTP (International Solar Terrestrial Physics Program). So far, SOHO represents the most comprehensive space mission devoted to the study of the sun and of the heliosphere. Within the collaborative mission, the functions are divided in the following way: ESA is responsible for S/C procurement, integration and testing; NASA provided the spacecraft launch and mission operations from GSFC. The following overall mission objectives are pursued: ^{1) 2) 3) 4) 5) 6)}

• Solar spectroscopy at soft X-ray and EUV wavelengths (study of the composition of the solar corona, of the structure and dynamics of the magnetic structures making up the corona, and of coronal holes, etc.)

• Study of the structure and dynamics of the solar interior through the observation of minute oscillations on the sun's surface (helio-seismology).

• Study of the solar wind and solar energetic particles, interaction with the Earth, plasma processes in both the solar and magnetospheric context.

The Solar and Heliospheric Observatory (SOHO) mission purpose is to study the Sun from a point of gravitational balance.

The SOHO spacecraft has been built by a European industrial consortium led by Matra Marconi Space (now Astrium) that was launched on a Lockheed MartinAtlas IIAS launch vehicle on December 2, 1995 to study the Sun, and has discovered over 2100 comets. It began normal operations in May 1996.

It is a joint project of international cooperation between the European Space Agency (ESA) and NASA. Originally planned as a two-year mission,SOHO currently continues to operate after over fifteen years in space. In October 2009, a mission extension lasting until December 2012 was approved.

In addition to its scientific mission, it is currently the main source of near-real time solar data for space weather prediction. Along with the GGS Wind and Advanced Composition Explorer (ACE),SOHO is one of three spacecraft currently in the vicinity of the Earth-Sun L1 point, a point of gravitational balance located approximately 0.99 astronomical unit (AU)s from the Sun and 0.01 AU from the Earth. In addition to its scientific contributions, SOHO is distinguished by being the first three-axis-stabilized spacecraft to use its reaction wheels as a kind of virtual gyroscope; the technique was adopted after an on-board emergency in 1998 that nearly resulted in the loss of the spacecraft.