Configuration Analysis And Design Optimization Of An Origami Meta-structure Solar Sail

Remote sensing satellites in Very Low Earth Orbits(VLEOs)benefit from obvious advantages including high spatial resolution and frequent revisit.However,the drag from the thin atmosphere causes significant orbital decay,which seriously influence the operation life.Utilization of solar radiation thrust to overcome air resistance provides a new way of orbital keeping.In this paper,a origami meta-structure solar sail based on reflective materials is proposed,which generates orbital-keeping propulsion force without causing additional atmospheric drag.This thesis documents the study on the meta-structure solar sail including configuration design,optical simulation,parameter optimization and model verification.Based on zigzag folding method,an origami configuration similar to optical gratings is proposed,which realizes unfolding,self-rigidization and in-plane optical propulsion.A parametric geometric model with 3 design constants and 7 design variables is established.The self-rigidization principle and folding characteristics of the solar sail are analyzed,and the overall configuration is determined.Numerical model is then developed according to the law of reflection to simulate the path of sun beam in the solar sail with multiple reflections.Solar radiation pressure generated from solar sails with arbitrary design parameters and incidence angles is simulated based on the quantum theory of light pressure,and the result is analyzed to comprehend the in-plane thrusting behavior.According to the typical lighting conditions in the 0°and-30°sun-synchronous orbit(SSO),the design parameters of the solar sails are optimized using exhaustion and inheritance method.Effect of the number of origami layers as well as material absorption rate on the optical thrust is analyzed.The maximum optical thrust of the six-layer solar sail is 3.8μN/m~2,which is even higher than that of the conventional flat-solar sails,which is 3.3μN/m~2,and is close to the theoretical upper limit of 4.3μN/m~2.This result for the first time verifies the concept of using zigzag-grating meta-structure for optical propulsion,which lays a foundation for further research.The maximum optical thrust of the seven-layer solar sail at-30°orbit is 1.1μN/m~2,which is lower than that of the traditional sail,which is 1.3μN/m~2,indicating that the in-plane thrust from meta-structure solar sail is more sensitive to the incident angle than conventional flat sails,though the latter is not a viable option for orbital keeping.In order to assess the practicability of this type of meat-structure solar sails in VLEO,case studies based on the geometric profile of Starlink satellites are carried out.The results show that a meta-structure solar sail with 5.22 m~2area can overcome the aerodynamic drag and achieve long-term orbit keeping in 500 km dawn-dusk orbit,while the-30°orbit requires 30.75 m~2.Considering that these solar sails are smaller than the 38.40 m~2of the Starlink solar panels,the concept is believed to be structurally feasible with current technology.If the solar sail area can reach 320 m~2,a long-term orbit keeping at 300 km altitude will be viable.To verify the optimization results,a test platform is built to test the reflecting lobe of a meta-structure solar sail model.The platform is designed,calibrated and the test program is written based on the required test precision.A test model with6-layer configuration and the optimal design parameters for dawn-dusk orbit is used in the tests.From the direction and relative intensity of the reflected beams,the direction of the optical thrust is evaluated,and the calculation is verified.