During its high-altitude phase, its flight control system would have been linked to ground stations and to space-based global navigation system navigation, while radar would have been used during the take-off and landing phases. In addition to the placing of satellites into geosynchronous orbit or LOE, HOTOL was also projected as being able to also perform the retrieval of satellites and hardware from LOE. BAe promotional material depicts HOTOL docking with the International Space Station (ISS), a feat that the company claimed would have required manned operation as automated systems were not capable of performing such docking manoeuvres at that time. HOTOL was designed to conduct fully automated unmanned flights; however, it had been intended at a later stage to potentially re-introduce a pilot. Manned operations would have required the installation of a dedicated pressurised module within the payload bay.