It was developed by Scaled Composites from 2007 to 2010 as the first stage of Tier 1b, a two-stage to suborbital-space manned launch system.
Razvila ga je tvrtka Scaled Composites u projektu koji je trajao od 2007. do 2010. kao prva faza Tiera 1b, dvofaznog suorbitalnog lansirnog sustava s ljudskom posadom.