*2.3.1 Standard 1553 data bus*

Existing commercial, civilian and military satellite data Busses have been using Military Standard 1553B (MIL-STD-1553B) data Bus for communications among satellite Bus and mission PL components. **Figure 5** describes a typical MIL-STD-1553B System [17, 27, 28]. This figure uses MIL-STD-1553B terminologies: (i) the Bus Controller (BC) is considered as an Intelligent Terminal (IT) that is located in the satellite mission computer, which is usually referred to as a Satellite Bus C&DH component, and (ii) Remote Terminal (RT) is considered as a slave terminal that is located in satellite platform components, which can be located in any satellite Bus or mission PL components.

**Figure 5** shows a typical commercial satellite system with RTs located in both satellite Bus and mission PL components. As an Example, the RTs located in satellite components are BAS, BADCS, BTCS and BTT&CS; and RTs located in the mission PL components are PAS, PTCS, PDPS, PTRANSEC, and PFTS. For military applications, the Mission Computer (MC) can be located in both satellite Bus and mission PL, where the MC in the satellite Bus is responsible for all control functions associated with the satellite operations and MC in the mission PL is responsible for all control functions related to the mission PL operations.

**Figure 5.** *Typical civilian and commercial MIL-STD-1553B satellite Systems.*

**Figure 6.**

*Typical civilian and commercial SpaceWire satellite Systems.*
