SOHO orbits around the L1 point, 1,500,000 km from the Earth.
The Spacecraft
The SOHO spacecraft is approximately 4.3 x 2.7 x 3.7 m3, it has a mass of 1861 kg of which 655 kg are instruments and 250 kg is fuel.
The fuel is used to move SOHO when adjustments to it's position are required. The power for day to day running of SOHO is provided by batteries which are recharged by the solar panels. The solar panels can provide a maximum of 1400 watts of power, though the instruments only use around 400-600 watts of electricity. This is about the same amount of power needed to use a regular microwave oven!!
SOHO is in orbit about the L1 point, which is about 1,500,000 km away from the Earth towards the Sun. This is the point where the pull of the Earths gravity and the pull of the Suns gravity cancel each other out, like the centre of a rope in a tug of war.
SOHO orbits this point to stabilise it's position. If it did not orbit, and was pushed slightly closer to the Sun, then the Suns gravitational pull would be stronger and the satallite would crash into the Sun, if it were pushed slightly closer to the Earth then it would crash into the Earth. The orbit around this point allows SOHO to balance between the Earth and the Sun as a tightrope walker balances on a rope.
SOHO was designed with a modular concept with two main modules, the Service Module (SVM) and the Payload Module (PLM). The PLM is the upper section on which all the instruments are mounted, the SVM is the lower part, which the solar panals are attached to, it contains the following systems: