On June 28, 2011, Pluto’s moon Kerberos was discovered by a team using the Hubble Space Telescope, led by senior research scientist Mark Showalter. While the primary goal of the observing program was to identify both potential targets and potential hazards for the then-upcoming New Horizons mission, Kerberos and its fellow moon Styx were also spotted during the investigation. Kerberos – originally referred to as S/2011 (134340) 1 and later named after the three-headed dog of Greek mythology – had been overlooked in earlier photos due to shorter exposure times. Scientists theorized Kerberos was large and dark, based on its faintness and gravitational influence. However, New Horizons images taken July 14, 2015, revealed a reflective moon, more diminuitive than expected, that was likely coated with water ice. The data also showed Kerberos has a double-lobed shape, suggesting it formed when two smaller objects merged.
