Missions in Space - Soho
Launch - 2 December 1995
The Solar and Heliospheric Observatory or SOHO is a joint NASA and ESA project to study the internal structure of the Sun, its extensive outer atmosphere and the origin of the solar wind - the stream of highly ionized gas or plasma that blows continuously outward through the Solar System.
Artist's impression of the SOHO telescope
© SOHO (ESA/NASA)
SOHO is helping us understand the interactions between the Sun and the Earth's environment better than has been possible to date. It can also warn us when solar flares or storms may pose a danger to Earth or its orbiting satellites, which can be affected or even damaged by the solar wind.
SOHO images showing how solar activity changes in an 11 year cycle
© SOHO (ESA/NASA)
SOHO was designed to observe the Sun continuously for at least two years, although it has now passed its tenth anniversary. All previous solar observatories have orbited the Earth, from where their observations were periodically interrupted as our planet got in the way of the Sun. To overcome this, SOHO observes from a point between the Earth and the Sun.
