The U.S. Air Force is pursuing a reusable booster system (RBS) to meet future responsive launch needs. An RBS consists of a reusable booster with and expendable upper stage. To meet operability and life cycle cost (LCC) goals, the current approach is for the RBS to return to the launch site (RTLS) after releasing the upper stage to avoid the need of operating a downrange base and avoiding the cost & time required to transport the vehicle back to the launch for the next mission. The RLTS approach discussed in this document is rocketback (sometimes referred to as boostback). This document is the first attempt to quantify the operational RBS rocketback flight envelope. Also discussed are trades on the RBS's vehicle design, specific mission scenario, and trajectory parameters that can affect the flight envelope.