Cassini spacecraft. Computer artwork of the Cassini spacecraft (upper right) after deploying the Huygens probe (lower centre) into Titan's atmosphere. Titan (right) is the largest moon of the ringed planet Saturn (left). Cassini was launched in October 1997 and will reach Saturn in July 2004. It will orbit Saturn for four years, studying the planet, its rings and its moons. The disc-shaped Huygens probe will enter Titan's atmosphere in January 2005. Front and rear heat shields will protect and deflect heat from the probe during atmospheric entry. The probe is expected to transmit data from Titan's surface for up to 30 minutes.