SwRI Flight Software Controls CYGNSS Components

SwRI's microsat Flight Software (FSW) was developed in the C Language, executing on the Centaur computer in the RTEMS real-time operating system environment. The modular architecture and components enabled efficient development and verification to directly supportg on-orbit modification. The FSW is table-driven and includes provisions for memory, table, and program image uploads. Application components interface through a software bus implementation (part of the Flight Core) to exchange CCSDS packets. Standard CCSDS protocols simplified the integration of application components and provided a reliable mechanism to install component stubs and simulations during software testing. During FSW development, the software bus was bridged to an Ethernet network via TCP/IP to permit the use of external simulators such as the Dynamics Simulator to test the Attitude Determination and Control Subsystem (ADCS).

RTEMS provides a small memory footprint and deterministic timing. Software development tools included the GCC compiler, the Aeroflex grmon debug monitor, and the SpaceBel Software Verification Environment (SVE).

The CYGNSS nanosat FSW team inherited code, as well as software development processes and practices, from MMS, WISE and other development programs at SwRI.


Related Papers

Software Engineering Process for Class D Missions

Simulators, Software and Small Satellites


Related Links

Southwest Research Institute: Avionics

 Latest Status
 Fact Sheet
 Systems Engineering
 Structural, Thermal & Mechanical
 Communication & Data System
 Electrical Power Subsystem
 Attitude Determination & Control
 Flight Software
 Deployment Module
 Assembly, Integration & Test
 Airborne & Ground Support  Equipment
 Launch Vehicle
 Mission Operations
 Contact Information

Website maintained by SwRI® Space Science & Engineering Division