Global Launcher Trajectory Optimization for Lunar Base Settlement

In the past few years, a new spirit for the exploration of the Solar System spread among the space community and reaching the Moon has been set as the first step of this new program. In this frame, going back to the Moon is needed to familiarize with a new way of living in a different environment, adapting to it and testing new technology. It is also true that, at the rate we are consuming the terrestrial resources, we will soon run out of them. This will put us in front of a dramatic change in our life style. Moreover, it is not unlikely that an asteroid could impact the Earth, causing extinction of many species and difficulties for survival. Then, these unpredictable reasons increase the importance of exploring and adapting to new extraterrestrial environments. Therefore, a feasibility study of a mission to the Moon to set up a permanent base has been carried on. The first part is concerning the delivery of the lunar payload into a LEO parking orbit. For this, the analysis of the capabilities of existing launchers is performed. The ascent trajectory problem is tackled by formulating it as an initial value problem (IVP), in which, given the launcher’s initial conditions, the state vector is propagated following a control law optimized to give the largest payload mass. Moreover, the launcher is subject to constraints dictated by the mechanical and thermal properties of the launcher itself. The optimal control law is sought by means of a Particle Swam Optimization method, which simulates the behavior of a flock of birds searching for food. Single and multi-objective optimization is performed. Single-objective optimization aims at maximizing the payload mass satisfying path constraints and the boundary constraints dictated by the orbital elements of the final orbit. Multi-objective optimization aims at maximizing the payload mass and minimizing the error on the final orbit simultaneously. Other experiments include the optimization of the two aforementioned objectives and the minimization of the violations of the path constraints. It has been found that, to fulfill the requirements of the lunar campaign, a very tight schedule and international cooperation is needed. Yet, existing launchers can be used for this mission for cargo expeditions. However, it is strongly suggested to commence development of a manned launcher and a spacecraft capable to land and host astronauts for multiple days on the Moon.Astrodynamics & Space MissionsSpace EngineeringAerospace Engineerin

Superior–subordinate dyads: Dependence of leader effectiveness on mutual reinforcement contingencies

Task contingencies were modeled from bureaucratic organizations in which vague job descriptions provide incomplete contingency specifications. Response rates within dyads were examined using two nonsocial, two social, and two control contingencies. In the first social contingency, responses by the superior produced monetary reinforcement for a subordinate while the superior received no reinforcement from his subordinate. A second social contingency was identical to the first except that the subordinate's rate of responding determined the rate of reinforcement delivered to his superior. Within this contingency, mutual reinforcement occurred whenever rates of superior and subordinate responding were correlated. Two control contingencies were identical to the second social contingency except that either the superior or the subordinate received a rate of response-independent reinforcement virtually identical to the rate received during the second social contingency. Leadership, in this context, was the difference between rates of subordinate responding produced by a nonsocial contingency and rates produced by each of the two social contingencies. The two nonsocial contingencies supported almost no responding among subjects. The first social contingency produced minimal levels of leadership within every dyad. The second social contingency produced high levels of leadership. Response-independent reinforcement generally reduced or eliminated responding