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Model-Based Off-Nominal State Identification and Detection


SBIR Phase II 2021 Model-Based Architecture for Responsive Spacecraft Autonomy

June 26, 2021

Okean Solutions culminated a 2-year SBIR Phase II project with the Air Force Research Laboratory for a high-fidelity prototype demonstration of a system that clearly shows how the MONSID® model-based fault management system can be used effectively on Space Superiority missions.

Why the Innovation is Important to the Air Force

Okean Solutions was awarded the Phase II contract, following a successful Phase I contract, under Topic AF131-092 On-Board Autonomy for Decreased Satellite Response Time.

The Air Force is interested in improving the capability of space assets to respond to real-time events, including faults. This topic seeks to develop and demonstrate technologies for embedded satellite autonomy. The topic cited model-based and constraint-based detection systems as examples of the types of technologies that were of interest to the Air Force. Since MONSID is a model-based system designed for on-board use, it directly supports Air Force needs. MONSID is dual-use as it has commercial applications, which is also aligned with stated Air Force and DoD goals to increase adoption of dual-use technologies.

Our Approach

We infused our MONSID system with Air Force Research Laboratory’s (AFRL’s) test and demonstration environment for a progressive, scalable architecture for evaluating onboard spacecraft autonomy.

The testbed is a 3 degree-of-freedom platform with spacecraft attitude control hardware and processors. During this effort we developed diagnostic models of testbed hardware, integrated MONSID with the testbed processors using NASA’s Core Flight System (cFS) framework and evaluated system performance via a test campaign.

Project Objectives

Phase II focused on providing onboard off-nominal state detection and isolation capabilities that are key components to assessing spacecraft state awareness.

Objectives intended to expand the application domain and improve MONSID fault management technology include:

  • Demonstrate the MONSID system in an AFRL test environment designed to integrate and evaluate spacecraft autonomy enabling technologies.
  • Provide the ability of the system to be built and tested standalone, potentially reducing FM developmental and testing costs.
  • Autonomously isolate spacecraft failures to component levels, thus enabling faster recovery and reducing down time.
  • Provide the capability to detect off-nominal behavior, including un-anticipated faults.
  • Produce detailed health status information that can then be used to make resource allocation and planning and scheduling decisions by ground operations or by other on-board autonomy agents.
  • Deliver a compact software package capable of running on resource-constrained computers similar to those used in flight.


The Phase II program successfully achieved objectives by completing the following:

  • Developed a MONSID model of the testbed hardware and available sensor suite capable of isolating faults to individual hardware units.
  • Integrated MONSID with testbed processors in the cFS framework, which is suitable for flight.
  • Designed and executed a test campaign with over 40 test bed runs created from variations of realistic mission scenarios including nominal and injected fault cases.
  • MONSID was able to verify nominal healthy operations as well successfully detect and accurately identify faults.

Test campaign highlights:

  • MONSID detected actual, unanticipated faults in the test bed hardware.
  • MONSID was able to effectively detect double faults, which is beyond the capabilities of most fault management systems.
  • MONSID was able to detect faults quickly and correctly and with low false positive rates, even with noisy data.

Potential Mission Infusion

MONSID FM software has the potential to satisfy the military’s requirements for space system robustness, specifically operational resilience of spacecraft to unexpected sensor and bus hardware faults and anomalous conditions. It can be implemented on the ground as a test aid during spacecraft Integration and Test (I&T) as well in an operations center for enhanced 'lights-out' automated telemetry monitoring. It can be migrated on-board reusing the same underlying models to provide cost-effective FM. Potential Department of Defense, NASA, and commercial uses include:

  • DoD technology demonstration missions and NASA CubeSat programs
  • DoD Space Situational Awareness missions such as future Geosynchronous Space Situational Awareness Program (GSSAP) satellites
  • Companies building and operating satellite constellations and other robotic assets for in-space manufacturing and surface mining
  • Space agencies such as NASA, ESA, and JAXA who operate orbiting deep space observatories and lunar and Martian rovers
  • The ARTEMIS campaigns will need MONSID capabilities for on-orbit assembly, lunar (and eventually) Martian surface mining and processing operations and maintaining safe habitat environments and power regeneration systems.

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