Kapp’s initial adrenaline rush wore off just as Starling II reached escape velocity. The crew breathed a collective sigh of relief. They had freed themselves from the gravitational pull of Earth to enter an orbit around the sun. The third and final rocket of the launch vehicle gave them the change in velocity needed to push them into an elliptical orbit, the path of least resistance between Earth and Mars. 

“Detaching stage three of the launch vehicle,” Jesse said, tapping away at...