Masten Space Systems Xombie

Vertical takeoff/vertical landing (VTVL) spacecraft made an important advance in May, when a demonstration spacecraft called Xombie, built by the Mojave, California–based firm Masten Space Systems, became the first of its kind to shut down its engine mid-flight, restart, and then land. The eventual goal is for unmanned VTVL rockets to rise to space and return several times a day, carrying zero-gravity experiments with each pass. The challenge is to carefully consume fuel throughout the trip so that the rocket has enough to land—hence the importance of Xombie’s success.  
masten-space.com