Complex sentence: On July 31,2013 the SLS passed the Preliminary Design Review (PDR), the review encompassed all aspects of the SLS' design, not only the rocket and boosters but also ground support and logistical arrangements.
Split into simpler sentences: On July 31,2013 the SLS passed the Preliminary Design Review (PDR). The review encompassed all aspects of the SLS' design, not only the rocket and boosters but also ground support and logistical arrangements.