Illustration of the ESAs (European Space Agency) Huygens probe descending toward the surface of Titan, the largest moon of Saturn. The probe, measuring 1.3 metres in width, was brought to Titan by NASAs (National Aeronautics and Space Administration) Cassini spacecraft (launched in 1997, not shown). On 14 January 2005, the probe penetrated Titans atmosphere and collected data during its 2 hour, 27 minute, 13 second descent to the surface. Huygens is seen here under its 8.3-metre diameter main parachute, which limits the descent speed to 580 kilometres/hour. The probe discovered that Titans atmosphere is primarily made up of nitrogen, with the existence of methane and ethane clouds.