Low-Thrust Spacecraft Attitude Path for Snap-Roll Power Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for controlling the attitude profile of low-thrust propulsion vehicles in space result in inefficient solar power generation during orbital transfers, as they either temporarily misalign solar panels to avoid snap-rolls or extend transfer time, leading to reduced energy supply or increased transfer duration.
Innovation Solution
A multi-step process involving generating a nominal attitude profile, identifying snap-roll events, defining time bounds, creating discrete control points, formulating a cost function to minimize solar power losses, and interpolating angular rates to optimize the attitude path, ensuring efficient solar power generation without extending transfer time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the attitude profile is adjusted to avoid snap-roll events, then angular rate constraints are satisfied, but solar power generation efficiency deteriorates
Solution Approach 1:
The system performs preliminary identification of snap-roll events in the nominal attitude profile before execution. By detecting potential snap-roll conditions in advance (when thrust vector and solar vector alignment would cause angular rate violations), the system can pre-calculate modified attitude profiles that avoid these events while minimizing impact on solar power generation. This preliminary analysis allows optimization of the attitude trajectory to maintain solar panel orientation as much as possible during orbit transfer.
Solution Approach 2:
The system dynamically adjusts the attitude profile by modifying angular velocity commands at identified snap-roll time bounds. Rather than using a fixed attitude profile, the system calculates time bounds around snap-roll events and generates dynamic control instructions that adjust angular velocity within these bounds. This dynamic adjustment allows the vehicle to navigate through potentially problematic attitude transitions while maintaining optimal solar orientation outside these bounds.
2Reliability
If transfer time is extended to avoid snap-roll events, then angular rate constraints are satisfied, but orbital transfer duration increases
Solution Approach 1:
The system performs preliminary identification of snap-roll events and calculates precise time bounds for each event before executing the orbital transfer. By knowing in advance when snap-roll events would occur, the system can plan attitude adjustments that are confined to specific time intervals rather than extending the overall transfer duration. This allows the vehicle to maintain nominal attitude and thrust direction outside these bounded intervals, preserving transfer efficiency.
Solution Approach 2:
The system identifies discrete time bounds around snap-roll events and concentrates attitude adjustments within these limited time windows. Rather than slowing down the entire transfer process, the system rapidly transitions through the problematic attitude regions during the identified time bounds and returns to the nominal attitude profile immediately after. This approach skips through the problematic regions efficiently without extending the overall orbital transfer duration.
3Reliability
If solar panels are misaligned to avoid snap-roll events, then angular rate constraints are satisfied, but solar power generation is reduced
Solution Approach 1:
The system applies local modifications to the attitude profile only in the specific regions where snap-roll events occur, rather than misaligning solar panels globally throughout the transfer. By identifying precise time bounds for each snap-roll event and calculating modified angular velocity commands only within these localized intervals, the system maintains optimal solar panel orientation during the majority of the orbital transfer. This localized approach minimizes the duration and magnitude of solar misalignment.
Solution Approach 2:
The system changes the angular velocity parameter dynamically within identified time bounds to avoid snap-roll events while minimizing solar misalignment. Rather than maintaining a constant offset between solar panels and sun direction, the system adjusts angular velocity commands temporarily within the calculated time bounds around snap-roll events. This parameter change approach allows the vehicle to satisfy angular rate constraints during critical transitions while returning to optimal solar orientation as quickly as possible.
Data Source
AI summary
A vehicle capable of computing an optimal attitude path that provides increased solar power generation through snap-roll events during orbital transfer maneuvers. A vehicle may include a memory and processor, including instructions, when executed can perform the steps of generate an attitude profile of the vehicle during an orbital transfer; identify, from the attitude profile, a snap-roll event; and generate instructions to adjust an angular velocity of the vehicle during a time period corresponding to the snap-roll event to satisfy a target angular velocity.