Complex sentence: On Apollo 17, Cernan became the eleventh person to walk on the Moon and, as the last man to re-enter the Lunar Module, he is as of 2017 the last man to have walked on its surface.
Split into simpler sentences: On Apollo 17, Cernan became the eleventh person to walk on the Moon and, as the last man to re-enter the Lunar Module. He is, as of 2017, the last man to have walked on its surface.