Floquet modes and stability analysis of periodic orbit-attitude solutions along Earth–Moon halo orbits

Future space programmes pose some interesting research problems in the field of non-Keplerian dynamics, being the Moon and the cislunar space central in the proposed roadmap for the future space exploration. In these regards, the deployment of a cislunar space station on a non-Keplerian orbit in the lunar vicinity is a fundamental milestone to be achieved. The paper investigates the natural orbit-attitude dynamics and the attitude stabilisation of coupled motions for extended bodies in the Earth–Moon system. The discussion is carried out analysing the phase space of natural dynamics, constituted by both the orbital and the rotational periodic motions of a spacecraft in cislunar orbits. Floquet theory is applied to periodic orbit-attitude solutions in lunar proximity, to characterise their attitude stability properties and their attitude manifolds, which are discussed and analysed focusing on their dynamical features applicable to cislunar environment. Attitude stabilisation methods are proposed and developed, with particular attention to spin-stabilised solutions. Periodic orbit-attitude dynamics are studied to highlight possible favourable conditions that may be exploited to host a cislunar space station with a simplified control action. The focus of the analysis is dedicated to halo orbits and near-rectilinear halo orbit in the circular restricted three-body problem Earth–Moon system.

The Geomorphological Factors and Its Implications for The Tidal Energy Installations in Java, Indonesia

This study aims to place the tidal energy installation effectively in Indonesia based on geomorphological factors. The survey method was used to analyze the characteristics of beaches in Indonesia. Mathematical physics model was implemented to find the new formulas based on geomorphological factors. Tides are the result of gravitational attraction and the centrifugal effect, which is the drive In the earth-moon system, tidal generating forces are the resultant forces that cause tides, namely: the earth-moon system (FS) centrifugal force and the moon's gravitational force (FB). FS works in the center of the mass of the earth-moon system whose mass point is located on the 3/4 radius of the earth. The style of tidal generator caused by the moon can be calculated by combining Newton's universal gravitational law .The results of this study consist of F = m ac, where the style of the tidal generator caused by the moon can be calculated by combining newton's universal gravitational law in equation and newton's second law of motion in Equation. The another results is tan = , where the formula takes into account constants (K) based on slopes. The last result is the constants (K) for each land form starting on 0,00 untill 1,00. The north coast of Java is more suitable for tidal energy installations because the land form is dominated by alluvium plains of the quaternary age with a lower risk than the southern region of Java. The effectiveness of tidal energy installation depends on the characteristics of the land form. In alluvial plains, the quaternary age of the alluvial plains is more suitable than the hill form volcanic quaternary, tertiary volcanic, and tertiary holokarst.