ZAP! Spacecraft discovers Saturn’s moon Hyperion is charged

Cassini spacecraft received the equivalent of a 200 volt electric shock from the electrostatically charged surface of Saturn's moon, Hyperion, confirming that objects in the outer Solar System can have charged surfaces, according to UCL research. The study, published in Geophysical Research Letters , reports that Cassini was briefly magnetically connected to the surface of Hyperion, allowing it to be caught by a beam of electrons coming from the moon's surface. Static electricity is known to play an important role on Earth's airless, dusty Moon, but evidence of surface charging on other objects in the Solar System has been elusive until now. The finding supports predictions that many different bodies including asteroids, moons and the surface of comets may be charged, which has wide-ranging implications, say the team. For example, astronauts may be at risk from strong electrostatic discharges when exploring planetary objects without atmospheres, like Earth's Moon. Hyperion is an irregularly shaped outer moon of Saturn, about 133 km wide, with a bizarre, sponge-like appearance owing to its unusually porous interior. The team believe it becomes charged when exposed to UV light from the Sun and plasma, which contains charged particles, in Saturn's magnetosphere - the invisible, movable bubble generated by the planet's internal magnetic field.