1. SPA Hardware Architecture

2. ReSpace 2011 SPA Network Stack Comparison of SPA to the OSI model

3. ReSpace 2011 Detailed SPA Network Stack Lower two layers are split across subnets SPA Messaging I2CI2C I2CI2C USB SpW Optical Socket SPA-1 Manager SPA-1 Manager SPA-U Manager SPA-U Manager SPA-S Manager SPA-S Manager SPA-O Manager SPA-O Manager SPA-L Manager SPA-L Manager xTEDS Application

4. ReSpace 2011 Each subnet has different power needs and bandwidth capability System engineer would select the most appropriate subnet for each device

5. ReSpace 2011 SPA Component Lifecycle Devices only have to send and receive messages No needed knowledge of the network topology

6. ReSpace 2011 SPA Methodology Data Centricity Traditionally getting data was all about location Read from COM4, 38400 Baud, no parity, XYZ sync characters... Changing a device from CAN to SPI meant modifying a significant portion of your FSW Publish/Subscribe Paradigm SPA allows data to be received regardless of physical locality or underlying physical transport mediums For example: A SPA application requiring IMU data asks the system who provides the needed data and a subscription is established SPA Network Interconnections Publish Subscribe IMU Application

7. ReSpace 2011 SPA Methodology Black Boxes Everything in SPA is treated as a “Black Box” Standardization occurs at the interface to each black box Black boxes may exist at different levels Processor Reaction Wheel Network A Power System Network B Payload ADCS App Radio Telem App Thermal App Orbit Prop Solar Array Batteries GSE Encrypted CCSDS Packets