Complex sentence: Styx is a small natural satellite of Pluto whose discovery was announced on 11 July 2012, and is to be imaged along with Pluto and Charon (Pluto's largest moon) by "New Horizons" in July 2015.
Split into simpler sentences: Styx is a small natural satellite of Pluto whose discovery was announced on 11 July 2012. It was imaged along with Pluto and Charon (Pluto's largest moon) by "New Horizons" in July 2015.