“Promethius and Pandora, two tiny moons of Saturn, have been straying. Chaotic interaction between them could be responsible for the perturbation of their orbits. The moons flank the F ring, which lies beyond Saturn’s main ring system, and is itself dynamically complex. The two moons are among the smaller of Saturn’s 18 satellites, and were discovered by the voyager space probe in 1980. Between 1994 and 2000, Richard French and colleagues detected gradual changes in the pairs orbits using the Hubble space telescope.”
p.907, Nature vol 421/