SOHO, the spacecraft

The upper section contains all the solar and other instruments. It's called the payload module. The SOHO instruments are used to:

• take images of the Sun in visible and UV radiation

• find out about the invisible material flowing from the Sun (the solar wind)

• measure the total amount of radiation coming from the Sun

• measure the Sun's vibrations

SOHO is about the same size as a large van.

The lower section of the spacecraft is known as the service module and it does a whole host of different jobs. It contains:

• a computer which collects all the observations from the instruments and an antenna which is used to send the information back to Earth.

• a special system which controls the temperature of SOHO to stop it getting too hot or too cold

• a guidance system which calculates SOHO's orientation in space and keeps it pointed directly at the Sun.