Session
Technical Poster Session 1
Location
Utah State University, Logan, UT
Abstract
As spacecraft geometries become more complex, particularly for In-Space Servicing, Assembly, and Manufacturing (ISAM) missions, higher fidelity models of shadowing are often necessary for more accurate planning and performance modeling in the mission operations center. For geometries where a vehicle may shadow a large portion of itself, these models must consider self-shadowing events, in addition to planetary eclipses, to provide an accurate estimate of forces and torques from Solar Radiation Pressure (SRP) and more realistic power generation estimates. SRP plays a pivotal role in determining spacecraft fuel usage and momentum accumulation. Many existing models simplify spacecraft geometries to either a spere or a simple box-and-array. These models do not consider self-shadowing and therefore may neglect important variations in SRP which affect resultant forces and torques on the body.
To provide the required fidelity, a ray tracing algorithm to compute self-shadowed elements of a spacecraft is presented. The algorithm is implemented in a faster-than-real-time simulation framework in MATLAB. The output from the ray-tracing algorithm is used to update ground-based estimates for un-shadowed cross-sectional area and solar array area to provide higher-fidelity estimates of SRP and spacecraft power generation. The enhanced estimates feed into ground planning tools to provide power-optimized thruster firings and improved operational insight. Results of this algorithm are also presented and compared to results from open-source space mission analysis software, such General Mission Analysis Tool (GMAT). Future improvements to the algorithm's implementation are discussed, along with recommendations for its integration with existing astrodynamics frameworks and ground segment software systems.
A Ray-Tracing Algorithm for Computing Self-Shadowing of Complex Spacecraft Geometries
Utah State University, Logan, UT
As spacecraft geometries become more complex, particularly for In-Space Servicing, Assembly, and Manufacturing (ISAM) missions, higher fidelity models of shadowing are often necessary for more accurate planning and performance modeling in the mission operations center. For geometries where a vehicle may shadow a large portion of itself, these models must consider self-shadowing events, in addition to planetary eclipses, to provide an accurate estimate of forces and torques from Solar Radiation Pressure (SRP) and more realistic power generation estimates. SRP plays a pivotal role in determining spacecraft fuel usage and momentum accumulation. Many existing models simplify spacecraft geometries to either a spere or a simple box-and-array. These models do not consider self-shadowing and therefore may neglect important variations in SRP which affect resultant forces and torques on the body.
To provide the required fidelity, a ray tracing algorithm to compute self-shadowed elements of a spacecraft is presented. The algorithm is implemented in a faster-than-real-time simulation framework in MATLAB. The output from the ray-tracing algorithm is used to update ground-based estimates for un-shadowed cross-sectional area and solar array area to provide higher-fidelity estimates of SRP and spacecraft power generation. The enhanced estimates feed into ground planning tools to provide power-optimized thruster firings and improved operational insight. Results of this algorithm are also presented and compared to results from open-source space mission analysis software, such General Mission Analysis Tool (GMAT). Future improvements to the algorithm's implementation are discussed, along with recommendations for its integration with existing astrodynamics frameworks and ground segment software systems.
