The Cassini-Huygens spacecraft comprises two components, the Cassini orbiter and the Huygens descent probe. In end June 2004, Cassini-Huygens arrived at the Saturnian system. The spacecraft will orbit Saturn for four years, sending scientific data and images of the planet and its moons back to Earth. In January 2005, nearly three weeks after separation from the Cassini orbiter, the Huygens probe entered the atmosphere of Titan and descended via parachute onto its surface. Huygens sent its measurement and image data to Cassini, which in turn relayed them to Earth.