Post Deployment Analysis MAGIC Tether Post Deployment Analysis

Deployed Tether Geometry Tip Mass (5kg) Velocity 20m Libration Angle Nadir Zenith Oscillating Frequencies: Roll Oscillating Frequency = 0.000368 Hz Pitch Oscillating Frequency = 0.000316 Hz Yaw Oscillating Frequency = 0.000177 Hz Main Structure (25kg)

Current Issues Tension and Libration Pendulum Motion Requires Accurate Deployment Tether Tape Material Properties

Tension Analysis For a 20m tether, Tension will be approximately 0.3mN. Tension this low could fail to provide adequate control in the pitch and roll axes of DINO. At low tension, tip mass and main structure would rotate freely until tension builds up.

Pendulum Motion Pendulum motion of DINO in the pitch and roll axes might not damp out over time. Accuracy of the deployment would define the pointing accuracy of DINO. ±10º off of nadir would be possible.

Material Properties Thermal Expansion (20x10-6mm/mm/K) 13.7cm expansion in sun Thermal Snap-Contraction (100x10-6/mm/mm/K) 68.6cm contraction in shade Stress vs. Strain of Tether Effective Modulus could differ from specs.

Conclusion Issues/Risks Recommendation Lack of Tension Pendulum Motion will not damp out Tether expands and contracts in and out of sunlight Recommendation A boom would be more rigid and could provide more predictable control. Build a emergency release mechanism for the tether if it is used and provide a backup such as a reaction wheel.

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