Orbit / Navigation
After a four-month journey the spacecraft reached its vantage point in orbit 1.5 million km nearer to the Sun than the Earth's own orbit. There at the Lagrange point L1, the gravitational pull of the Sun is balanced by the pull of the Earth and the centrifugal force acting on a spacecraft obiting in step with the Earth. SOHO can therefore remain hovering around that relative position, in a "halo orbit", while it accompanies the Earth in its annual march around the Sun. The spacecraft completes one revolution in its halo orbit around L1 roughly every 6 months.