The following assumptions were made to constrain the SD-stage modifications. First, only the minimum number of changes would be allowed to the stage to get the job done. The system would not be needed for range extension since the missiles which would most likely use this system, the Mod CSS-4 and the DF-41, would have sufficient range already. The system would deploy three 470-kg Dong Feng 31 (DF-31) RVs. The system would not contain penetration aids (penaids). In addition, all 12 pitch/yaw thrusters would be used for axial thrust. Furthermore, it was assumed that these 70 N thrusters could withstand the full 128 second continuous burn. Additionally, the modified SD stage would have 20 degree/second rotation and turn rate. Lastly, the payload shroud would have a mass of about 200 kg and would be jettisoned early during second stage burn.