Static and dynamic evaluations for large square solar sail concept based on scalable prototype validation

Highlights

• The simulation and analysis method for solar sail is validated by scalable prototype.

• Wrinkles of sail are simulated based on buckling theory and validated by experiment.

• Static deformation, stress and wrinkles are analyzed to evaluate 160 m sail concept.

• Transient dynamic responses of 160 m sail with different parameters are provided.

Abstract

This study aims to propose a static and dynamic evaluation for 160 m solar sail by comparing the results obtained using an 8 m scalable principle prototype. Based on the model updating and parameter modification theories, the finite element analysis (FEA) model of the 8 m prototype is constructed, and results are obtained to validate the effectiveness of the proposed numerical simulation method. The static deformation is compared with experimental data with errors in acceptable limits. Moreover, the numerical simulation and analysis method for wrinkle patterns are also applied based on the structural buckling theory and linear combination technology. The calculated indices of peak-valley value, half-wavelength, and wrinkle number are compared with the prototype experiment. By validating the numerical simulation approach in the 8 m prototype, the same analysis method can be directly extended in the application of the 160 m solar sail. The deformation response of the overall system and wrinkle patterns of the 160 m sail are provided. The transient dynamic responses of acceleration, displacement, and vibration amplitudes are also simulated and compared using different parameters. All the results obtained herein provide valuable suggestions and reference to large solar sail design in the future.

Introduction

The solar sail is an advanced propulsion spacecraft driven by solar radiation pressure, which offers a long operating lifetime without any fuel consumption [1,2]. Unlike conventional propulsion spacecrafts, the solar sail can operate in many orbits, such as the Mercury sun-synchronous polar orbit [3], displaced geostationary orbit [4], and displaced heliocentric orbit [5]. Therefore, the deep space exploration, Earth measurement and other missions can be realized using solar sails. Moreover, as the basis of other advanced spacecrafts such as the space solar power satellite [[6], [7], [8], [9]] and deployable membrane antenna [10,11], the dynamics of the sail membrane is a key factor that directly influences the characteristics of the vibration, attitude, and orbit etc, among others, of the spacecraft.

Solar sails have been investigated for many decades in mission, concept, material and dynamics. A limited number of sail-crafts have been tested in the attitude and orbit control system [[12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22]]. It is well known that structural static and dynamic characteristics represent the most important factors determining the performance of a solar sail, which can directly influence the attitude and orbit in the space. Moreover, the design, analysis, and optimization of solar sails are all based on the static and vibration response. Recently, several studies have been conducted based on sail dynamics [[23], [24], [25], [26], [27], [28]]. By comparing the various design conditions and parameters in five kinds of square sails, Greschik et al. [23] proposed the achievable performance and provided some key structural characteristics for the 100-m square solar sails with simple and useful theories and calculated expressions. Meanwhile, as is well known, solar pressure exerts a force on the sails and increases the temperature synchronously. Therefore, Kezerashvili [24] suggested that a required minimal thickness of the sail should be determined using the relation between the solar pressure and elastic deformation of the material, which should be taken into consideration in the solar sail design. Based on the assumed deformation of the sail film in response to the support beam, Liu et al. [25] investigated the exact thrust parameters using the Von-Karman's nonlinear strain-displacement relationships and Newton iteration method. By attaching each blade tip to a formation-flying tip satellite, Woo et al. [26] proposed the near-elimination of sail supporting structures. To reflect on the feasibility of the folding and unfolding processes and to investigate the modal properties, Wei et al. [27] presented a deployable sail with four triangular membranes supported by inflated booms, whose stiffness was supported by four self-supporting thin shells on the inside and a Velcro outside.

Numerical simulation is an important tool for analysis of dynamic responses without huge costs. As one of the most widely used numerical simulation approaches, FEA has been successfully applied to simulate and analyze the solar sail system. To address the numerical convergence issues in simulation of the sails, Boni et al. [29] proposed an approach by means of suitable strategies. By referring to von Beck's problem, Stanciulescu et al. [30] investigated the numerical difficulties of the solar sail associated with the cases of buckling under non-conservative loading, and suggested prediction of the post-buckling behavior. According to the parametric studies using FEA, Sleight et al. [31] studied a series of effects generated by sail size, sail membrane, and boom parameter. Using simulation technology and parametric discussion, Jenkins et al. [32] investigated measurement needs, related aspects of measurement technologies, and dynamic parameter challenges for solar sails. To investigate the key matters of solar sail technology, Sleight et al. [33] studied a comprehensive test program for solar sail design that is validated by FEA parameters. As is well known, the membrane wrinkle is a classical characteristic in solar sail, and some numerical simulation methods [34,35] have been applied in solar sail analysis. Tessler et al. [36] demonstrated mesh refinement, stress-concentration alleviation and effects of these parameter strategies to membrane wrinkles. Some of their results on wrinkles can yield useful suggestions regarding the solar sail shape analysis. Considering the measurement uncertainties and errors that exist in large high-precision spacecraft, Yang et al. [8] proposed an interval surface accuracy evaluation method for membrane-spacecraft based on a non-probabilistic approach. Recently, an 8 m scalable solar sail prototype was constructed by Qian Xuesen Laboratory of Space Technology, China Academy of Space Technology (CAST), and its statics and wrinkle experiments have been tested [37,38]. However, the simulation and analysis have not been obtained and compared. In addition, they have not extended and suggested to the large solar sail concept yet.

According to the literature mentioned above, many valuable studies have investigated the dynamic and static performances and characteristics of the solar sail. However, some details have not been reflected previously. Some valuable studies mainly focused on the larger sail concept while others considered the performance of the scalable sail. However, the relation and discussion between the larger concept and the scalable prototype has not been systematically investigated. Additionally, independent of whether the study concerns the larger sail concept or small sail scalable prototype, the wrinkle patterns in the sail membrane were not investigated to date. The wrinkle shapes are very important in the initial design process of the solar sail and can directly determine the thrust efficiency and influence the orbit and attitude in space. Moreover, the transient characteristics were previously not considered using simulation technology that is validated by the experiments. In our opinion, the initial design of the solar sail without the abovementioned considerations in the analysis process and results may cause errors and inaccuracies.

Therefore, the shortcomings of the former studies of static and dynamic analysis in solar sails are all listed clearly. This study aims to bridge the gap between these studies. In this study, static and dynamic evaluations for the 160 m solar sail concept are generated by comparing with the 8 m scalable prototype testing results. Then, to validate the effectiveness of the numerical simulation method, the FEA parameter and analysis method of the 8 m prototype is constituted based on parameter modification and model updating. Furthermore, the numerical simulation and analysis method for wrinkle patterns is also applied by the means of structural buckling theory. The detailed indices of the peak-valley value, half-wavelength, and wrinkle number are compared with the prototype experiment. Therefore, the same analysis method can be directly extended to application of the 160 m solar sail concept by validating the numerical simulation approach in the 8 m prototype. The deformation responses of the overall system and wrinkle patterns of the 160 m sail are all provided. The transient dynamic responses of acceleration, displacement, and vibration amplitude are also simulated and compared at different parameters.

The paper is organized as follows. Research route is introduced in Section 2 to demonstrate research motivation of this study, the r. The experiment of the 8 m solar sail scalable principle prototype by the Qian Xuesen Laboratory of Space Technology CAST is shortly reviewed in Section 3. The simulation analysis validated by the 8 m prototype including model updating, statics, and the membrane wrinkles are provided in Section 4. The simulation method is extended and applied to the 160 m solar sail concept including statics, wrinkle, and dynamics in Section 5 to provide valuable suggestions and references of the proposed works with the large solar sail design. Finally, a few words of summarization and conclusion on this study were given in Section 6.