So why exactly did the crew International Space Station need those HoloLens headsets? For a holographic instruction manual and VoIP calls, of course. Prior to entering orbit, the headset was certified for use on the Weightless Wonder C9 a number of times to ensure it'd work in a zero-G environment in addition to the NEEMO underwater space station analog, according to Victor Luo, the technical lead of NASA's Jet Propulsion Lab. Astronaut Scott Kelly used it to make the first Skype call from outer space to mission control and says he fiddled around with it for about two hours, too.