The Cassini-Huygens spacecraft, a joint project of the US space administration (NASA), the European Space Agency (ESA) and the Italian space agency (ASI), has discovered two more small moons orbiting the planet Saturn, bringing the total to 33. The moons, which have provisionally been dubbed S/2004 S1 and S/2004 S2, are approximately three and four kilometres across and are orbiting at distances of 194,000 and 211,000 kilometres from Saturn's core respectively. They were first spotted by Dr Sebastien Charnoz, a planetary dynamicist working with the mission's imaging team at the University of Paris. Until now, the smallest moons known to be orbiting Saturn were around 20 kilometres across, but scientists suspected they might find moons the size of S/2004 S1 and S2 in the gaps between the planet's giant rings. Interestingly though, the new moons are located outside the rings between the orbits of two other Saturnian moons, Mimas and Enceladus. It had been expected that small comets in the outer Solar System would long since have collided with moons of such diminutive size and broken them up, so the very existence of S/2004 S1 and S2 may suggest a limit to the actual number of small comets in the region beyond Neptune known as the 'Kuiper Belt'. Despite this discovery of two tiny moons in an unexpected location, Cassini-Huygens will be producing more imaging sequences of the gaps between Saturn's rings to look for other small satellites which scientists still believe they will find there.