Complex sentence: The KH-12, commonly known as "Advanced Key Hole", also known by the codenames Ikon and Improved Crystal, is a successor to the KH-11 reconnaissance satellite and also used digital imaging.
Split into simpler sentences: The KH-12 is a class of satellites, commonly known as "Advanced Key Hole", also known by the codenames Ikon and Improved Crystal. It is a successor to the KH-11 reconnaissance satellite and also used digital imaging.