Fact Sheet
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SOHO (SOlar Heliospheric Observatory) is a space-based observatory, viewing and investigating the Sun from its deep core, through its outer atmosphere - the corona - and the domain of the solar wind, out to a distance ten times beyond the Earth's orbit.
Mission Objectives
SOHO is designed 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 that blows continuously outward through the Solar System.
SOHO is helping us understand the interactions between the Sun and the Earth's environment better than has been possible to date. Its legacy may enable scientists to solve some of the most perplexing riddles about the Sun, including the heating of the solar corona, the acceleration of the solar wind, and the physical conditions of the solar interior. It gives solar physicists their first long term and uninterrupted view of the Sun. This opposed to all previous solar observatories that were placed in an orbit around Earth from where their observations were periodically interrupted as our planet 'eclipsed' the Sun.
Mission Name
SOHO stands for SOlar Heliospheric Observatory.
Spacecraft
SOHO is a three-axis stabilised spacecraft. It is made up of two modules: the Service Module that provides power, control, pointing and telecommunications for the whole spacecraft and support for the solar panels, and the Payload Module that houses all the scientific instruments.
- Mass: total at launch 1850 kg payload 610 kg
- Dimensions: breadth and width: 3.65 × 3.65 m, span with solar array deployed 9.5 m
- Launcher: Atlas-IIAS
- Mission lifetime: SOHO was launched from Cape Canaveral Air Station on 2 December 1995, 08:08 UT, and was designed to observe the Sun continuously for at least two years, but is still observing!
Instruments
| CDS | Coronal Diagnostics Spectrometer Rutherford Appleton Laboratory, United Kingdom |
| CELIAS | Charge, ELement, andIsotope Analysis System Universität Bern, Switzerland |
| COSTEP | COmprehensive Supra Thermal and Energetic Particle Analyzer University of Kiel, Germany |
| EIT | Extreme ultraviolet Imaging Telescope NASA/Goddard Space Flight Center, USA |
| ERNE | Energetic and Relativistic Nuclei and Electron experiment University of Turku, Finland |
| GOLF | Global Oscillations at Low Frequencies Institut d'Astrophysique Spatiale, France |
| LASCO | Large Angle and Spectrometric COronagraph Naval Research Laboratory, USA |
| MDI/SOI | Michelson Doppler Imager/Solar Oscillations Investigation Stanford University, USA |
| SUMER | Solar Ultraviolet Measurements of Emitted Radiation Max-Planck-Institut für Aeronomie, Germany |
| SWAN | Solar Wind ANisotropies FMI, Finland; Service d'Aeronomie, France |
| UVCS | Ultra Violet Coronagraph Spectrometer Harvard-Smithsonian Center for Astrophysics, US |
| VIRGO | Variability of Solar IRradiance and Gravity Oscillations from ESTEC, The Netherlands |
Orbit
SOHO is operated from a permanent vantage point 1.5 million kilometres sunward of the Earth in a halo orbit around the Lagrangian point L1.
Operations Centre
SOHO is commanded from NASA's Goddard Space Flight Center (GSFC) in Greenbelt, Maryland (USA). Its data are retrieved via the NASA Deep Space Network (DSN).