Modular Line-Focused Space Solar Power Satellite

The Space Solar Power Satellite is an ultra-large space structure, which collects sunlight directly in space and then transmits it into the ground. Since the idea was invented in 1968, scientists around the world have proposed several typical conceptual design models. Nevertheless, the conceptual models have not been implemented for technological, manufacturing, and cost reasons. This paper presents a novel Space Solar Power Satellite scheme with modular line-focused concentrators and low concentration photovoltaic modules. First, the line-focused mode is analyzed and the optical performance of the circular trough concentrator is evaluated via ray-trace technique. Then, shape optimization for the cell array based on the Bézier curve is carried out to improve the optical property. Numerical examples indicate that the optimized cell array could obtain high power collection efficiency and suitable energy distribution. Moreover, the area of the photovoltaic cell array is reduced, which is conducive to cost reduction. Furthermore, modular design is conducted on the circular trough concentrator. Finally, the primary scheme of the novel Space Solar Power Satellite is designed with the previous modular concentrator and optimized cell array.

Active vibration suppression for large space structure assembly: A distributed adaptive model predictive control approach

Subject to the limited envelope size and carrying capacity of a rocket, it could be one of the most promising solutions to construct a large space structure through multilaunching and on-orbit assembly. Taking the antenna of the solar power satellite as the research objective, a novel vibration suppression strategy is developed in this article to guarantee high structural stability of the large space structure during on-orbit assembly. The concept of distributed control unit, together with the varying location relationship matrices, reflects the structural characteristics of the large space structure during on-orbit assembly. The explicit expression form of the control unit’s dynamic model is first derived based on the Newmark-β method. Then, the distributed adaptive model predictive controller is proposed to suppress the vibration of the large space structure aroused by weak impact among assembling modules. Through recalculating the control matrices efficiently at each assembly, the proposed controller achieves adaptive updating along with the varying large space structure. The feasibility of the proposed distributed adaptive model predictive controller is investigated in the numerical simulations, and the centralized fast model predictive controller is adopted for better comparison. The results demonstrate that the distributed adaptive model predictive controller can effectively suppress vibration of the large space structure during on-orbit assembly, with good adaptability, robustness, and computation efficiency.

Performance-Based Analysis of Older-Type Large-Space Hall in Fire

The paper presents the example of performance-based analysis for the existing large-space steel structure raised in 1980s. Hall is used as a paper products warehouse. Advanced mechanical simulations are performed using Safir software. Factors that impact the final fire resistance of the structure are discussed. Local and global imperfections and possible ways of structure modelling are taken into account. For selected cases advanced fire scenario that considers both localised fire and possibility of further ignition of stored goods is prepared using Fire Dynamics Simulation software. The results obtained indicate that added imperfections have little impact on the fire resistance of the structure and older-type steel hall roof without any fire protection could survive 30 minutes of fire. Main failure modes and values of structure’s deflections are also presented. Finally, performed simulations show that even for large-space structure the flashover is possible in some special cases.

Mathematical modeling of transformable space structure dynamics

Today large space structures are in focus of attention of engineers and designers of rocket and space equipment. In ground-based experiments, it is not always possible to carry out complex tests of large space structure functionality. Therefore, the development of mathematical models describing properly the transformable structure dynamics when they opened from the densely packed transport state to the operating position in the orbit becomes very important. To determine the stress-strain state of the frame elements when it is unfolding the shape of the framework is taken at the moments when relative velocities of the adjacent sections are maximal. Supposed, that at these moments the frame elements are getting on the stops limiting their relative angular displacements, and the structure behaves as an elastic rod with specified characteristics. Numerical analysis of the stress-strain state in the framework is carried out by means of a finite element model. Therefore, the represented mathematical model can be effectively used to predict the functional suitability of such transformable space structures already on the early stages of their development.