Due to a design oversight, the combined booster and lifter Δv comes out to 3.756km/s, which is 306m/s more than is needed for insertion into 75km LKO. Because we want the lift stage to de-orbit the decision was made to manually stage just prior to positive perikee during the orbital insertion burn. When staged, the engines are supposed to cut but that mechanism failed for some reason and the 3 main engines continued to push against the craft. The loss of firm connection between the stages caused a shift in mass balance that began to torque the craft around radially until the engines flamed out and the stage could finally be left behind under power of the transfer engine. It now resides in a stable orbit and will not be returning without a mission to go up and knock it down
