SOHO
Temperature map of the Sun's corona. Credit: SOHO/EIT (ESA & NASA)
Addressing these questions:
Project Status:
UK Involvement
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The Solar and Heliospheric Observatory (SOHO) is an ESA/NASA mission launched
in 1995. The objective of SOHO is improve our understanding of the processes
involved in heating the corona, creating coronal mass ejections and
accelerating particles in the solar wind.
Scientific Impact
SOHO carries three sets of instruments designed to explore the solar interior
using a method known as helioseismology which involves monitoring small
vibrations of the Suns surface by exploiting the Doppler Effect (a shift in
wavelength of emitted light due to motion) or variations in intensity. The
application of a consistent synoptic programme for SOHO has resulted in a
dataset which is ideal for solar cycle and long-term variation studies.
Strategic Priority
The mission addresses the two themes of energy flow in the solar system
and how the interior of the Sun couples with the solar surface and atmosphere.
Timeliness
The extended ESA/NASA mission runs to December 2009.
Track Record
The UK has unique hardware capabilities as demonstrated by PI participation in
all major solar missions, as well as requests from US teams for UK
collaborators.
Momentum
The SOHO mission has been extended several times, the nominal end date is
2009 and the mission has been operating for over 10 years. the current end
date allows significant overlap between SOHO and Solar-B and STEREO
(both with launch dates in 2006) and Solar Dynamic Observatory (SDO)
(launch 2008). This provides UK scientists with an outstanding complement
of instrumentation for solar research.
UK Involvement
The UK involvement is as PI on the Coronal Diagnostic Spectrometer (CDS)
through the CCLRC's Rutherford Appleton Laboratory with the assistance of UCL's
Mullard Space Science Laboratory. The CDS is one of the main
instruments on SOHO. UK theoreticians played an important role in the design of
the Global Oscillations at Low Frequencies (GOLF), Solar Oscillations
Investigation (SOI) and the Variability of Irradiance and Gravity Oscillations
(VIRGO). The UK Post Launch Support concentrates on CDS operations.
Cost
The UK Post Launch Support cost £5M from launch to April 2005
