It was frequently emphasized by the U.S. Air Force that, unlike the NASA programs, Dyna-Soar allowed for controlled re-entry, and this was where the main effort in the X-20 program was placed.
但是，美国空军时常强调，与NASA不同的是，Dyna-Soar可以在有人控制的情况下重返大气层，这也是X-20计划的主要研究方向。