**5. Future resilient and robust satellite system architectures**

This section demonstrates how to use Steps II-A and II-B of the proposed MOSA implementation approach presented in Section 4.4 for the design and build of future resilient and robust satellite systems. Subsections 5.1 and 5.2 present potential modular-and-open satellite Bus and mission PL architectures, respectively.

#### **5.1 A potential modular open satellite bus architecture solution**

To demonstrate how to transition the notional modular satellite Bus system architecture presented in **Figure 3** to a modular-and-open satellite Bus architecture, this subsection provides an example for the transition of three modular Bus subsystems, namely, BC&DH (Bus Subsystem 3), BTT&C (Bus Subsystem 4) and BEPS (Bus Subsystem 5). These modular Bus subsystems are decomposed to subsystem component-level and analyzed for consideration as potential KOSS's for open interface standardization. **Table 1** summarizes the decomposition and analysis results for these three satellite Bus subsystems.

In practice, the preliminary KOSS analysis results shown in **Table 1** should be finalized by the system designer using DOD KOSS tool discussed in Section 4.4. As shown in **Table 1**, standardizing the BC&DH data interfaces will probably provide the biggest return on investment since the BC&DH subsystem interfaces with each onboard system. Incorporation of the timing interface along with the data interface will minimize the amount of connections, thus reducing overall system mass. Any

<sup>4</sup> OAAT from: https://www.dau.mil/cop/mosa/Lists/Tools/DispForm.aspx?ID=1&ContentTypeId= 0x01002 BC08FCA204040449CF11CB472BEEE1800AA6D1BC9926604469A02DDB936F94D1F

<sup>5</sup> KOSS from: https://acc.dau.mil/adl/enUS/317012/file/46502/KOSS%20Overview\_FINAL\_5Aug09.pdf.



**Table 1.**

*Satellite bus subsystems decomposition and potential KOSS.*

interfaces that require a significant amount of analysis or Non-Recurring Engineering (NRE) hours is not a good candidate for standardization. The fault management processing interface is in this category, and it is not recommended for standardization.

#### **5.2 A potential modular open Mission payload architecture solution**

This subsection provides an example for the transition of the notional modular mission PL architecture presented in **Figure 4** to a modular-and-open mission PL architecture. **Table 2** summarizes the decomposition and KOSS analysis results for four mission PL subsystems, including PAS (PL Subsystem 1), CPCom-RFS (PL Subsystem 2), PDPS (PL Subsystem 3) and PFTS (PL Subsystem 11).

The mission PL digital processing system is not recommended for interface standardization due to many variations between systems and subsystems. Multi-RF Wideband RX Up/Down Converters and Tunable IF Down Converters require a significant amount of analysis or NRE hours and are also not a good candidate for standardization. Again, DOD KOSS tool should be used to finalize the KOSS analysis results presented here for actual design and build of the satellite systems.

#### **6. Conclusion**

The chapter provides an overview of existing modular satellite Bus and mission PL architectures and associated standards for communication data Busses. The chapter defines open and close interfaces along with industry approved popular standards and discusses the interface design challenges. Moreover, the chapter provides an overview of MOSA and related DOD guidance and assessment tools to address the interface design challenges. Examples for the design and build of modular-and-open satellite Bus and mission PL architectures are also presented. The intent of this chapter is to provide an innovative approach for the satellite system designer to design and build of the next generation satellite achieving a balance between business and technical objectives that make a business sense for both the satellite manufacturers and buyers in terms of lower system acquisition and sustainment costs over its life cycle. The MOSA implementation approach presented here allows the satellite manufacturers to build the satellite Bus and mission PL separately for more production, flexibility, and market competition. Concurrently, the approach also allows the satellite buyers to buy satellite Bus at high volume with reduced unit costs and less schedule risk. Another benefit for the


*Future Satellite System Architectures and Practical Design Issues: An Overview DOI: http://dx.doi.org/10.5772/intechopen.92308*

**Table 2.**

*Mission payload subsystems decomposition and potential KOSS.*

satellite buyer is the adaptability of changing the requirements on the mission PL without impacting the satellite Bus.

### **Acknowledgements**

Although the preparation of this work was not funded by The Aerospace Corporation, but the author acknowledges the work presented in this chapter was based on his knowledges accumulated over the years from many space programs at The Aerospace Corporation, Raytheon and Jet Propulsion Laboratory. In addition, the author would like to express his appreciation to Aerospace's manager, Ms. Navneet Mezcciani, for her professional support.
