Precision Alignment Determination and Control System for a Precision Formation Flying Distributed Spacecraft Mission (DSM-PFF)

Many proposed science missions use separated optics and detectors on free-flying platforms, maintained in very precise alignment to form a new type of science instrument using precision formation flying (PFF).  We plan to develop and validate a guidance, navigation, and control (GN&C) system for the precise inertial alignment control needed for this type of dual-platform distributed spacecraft mission. This project will develop a highly precise, scalable GN&C system architecture to achieve the challenging inertial alignment goals for this unique type of PFF. A complete GN&C system for demonstration of the acquisition and precision inertial alignment will be developed using previously developed IRAD GN&C analysis tools.

The objective of this project is to develop and validate a complete scalable GN&C system for a precision formation flying (PFF) distributed spacecraft mission (DSM) design reference Mission (DRM). We will develop Guidance, Navigation, and Control (GN&C) system component requirements, algorithms, and software for the precise determination and control of an actively controlled spacecraft to meet the formation alignment
specifications. Our project will specifically address the technology gap of the systems needed to achieve these DRM-PFF formation alignment specifications.

The navigation system development will incorporate various proposed relative and inertial alignment measurement components into a complete system architecture for overall platform position and attitude state estimation to meet alignment knowledge requirements. Our team will work closely with other IRAD teams developing component technologies to refine system design and component requirements to meet our objectives. This analysis will lead to a complete system navigation filter design and analysis.

We will develop an end-to-end alignment control and disturbance isolation system based on DRM-PFF specifications. System component architectures and component specifications will be developed considering performance that can be obtained from technologies under development and available in the near term for utilization on proposed missions. A complete GN&C system will be analyzed, verified, and validated in a Matlab/Simulink high fidelity simulation. This effort will focus of verifying system performance and operational strategies needed to demonstrate end-to-end GN&C performance and robustness. Our work will focus on development, verification, and validation of an end-to-end GN&C system to a high level of maturity that can be included in future proposals for technology demonstration and/or science missions.

A secondary objective will be to develop specifications and prototype demonstration hardware for an ultra-precise stellar camera system for inertial alignment measurements to achieve high precision inertial alignment goals of the DRM-PFF. There are many options for inertial alignment using commercial-off-the-shelf (COTS) star trackers. But, these are limited to arc-sec level inertial performance. This effort will focus development of an alignment camera system with the goal of milli-arc-sec level performance with size, weight and power (SWaP) that are typical for spacecraft bus components.