German contribution to the X-38 CRV demonstrator in the field of guidance, navigation and control (GNC)

In the frame of the ESA/NASA cooperation on the X-38 project, different GNC-related contributions have been made by German industry and universities. First, the primary flight control software for the autonomous guidance and control of the X-38 parafoil descent and landing phase has been developed, integrated and successfully flown during the aerial drop test campaign conducted by NASA. In addition, a fault-tolerant computer similar to the one used onboard the ISS has been delivered to JSC. Together with an alternate re-entry GNC software using onboard flight path optimization for the guidance task and dynamic inversion methods for attitude control, this computer shall be flown as a flight experiment onboard the V201 space flight test vehicle. Finally, the German project team provided a real-time X-38 vehicle simulator, which was supposed to be used as an independent validation tool for the X-38 re-entry simulation and onboard software. This paper will focus on the European parafoil guidance and control software across the different phases of the X-38 mission. Flight test results from the X-38 aerial drop test campaigns will be presented and discussed. In addition, the flight experiment of the fault tolerant computer will be described briefly.