... With enough velocity, a spacecraft can break loose from the Earth's gravity and enter an orbit around the Sun, like that of a planet. If it then orbits the Sun with the same period as the Earth--one year--it may keep a fixed position relative to Earth. ... If the distance is just right--about 4 times the distance to the Moon or 1/100 the distance to the Sun--the spacecraft, too, will need just one year to go around the Sun, and will keep its position between the Sun and the Earth. ...

... une distance de 6. 6 rayons de la terre (42,000 km soit 26,000 milles), ces satellites accomplissent une orbite par jour , donc tournent avec la terre, et restent toujours au-dessus du m?me point de celle ci. ... terre. ... Encore une autre application est le r?seau de 24 satellites du " Syst?me de Position Global(mondial) " (GPS), sur des orbites circulaires distantes d'environ 4.1 rayons de la terre (26,000 km soit 16,000 milles). ... La derni?re d'entre elle par une bombe t?l?guid?e par GPS. ...

Phoebe . Saturn IX . Phoebe [FEE-bee] is the last of the known satellites of Saturn, at a distance of 12.952 million kilometers (8 million miles). Phoebe orbits Saturn in a retrograde direction (opposite to the direction of the other satellites' orbits) in a plane much closer to the ecliptic than to Saturn's equatorial plane. ... Scientists believe that Phoebe may be a captured asteroid with a composition unmodified since the time it was formed in the outer Solar System . ...