Complex sentence: Eisele required surgery for a dislocated shoulder, which he sustained aboard the KC-135 weightlessness training aircraft, and was subsequently reassigned to a second Apollo crew, to be commanded by Wally Schirra.
Split into simpler sentences: Eisele required surgery for a dislocated shoulder, which he sustained aboard the KC-135 weightlessness training aircraft. He was reassigned to a second Apollo crew, to be commanded by Wally Schirra.