Mingying Huo, Giovanni Mengali and Alessandro A. Quarta
The aim of this paper is to discuss E-sail-based missions (E-sail – electric solar wind sail) towards Venus and Mars. The analysis takes into account the real three-dimensional…
Abstract
Purpose
The aim of this paper is to discuss E-sail-based missions (E-sail – electric solar wind sail) towards Venus and Mars. The analysis takes into account the real three-dimensional shape of the starting and arrival orbits and the planetary ephemeris constraints by using the Jet Propulsion Laboratory (JPL) planetary ephemerides model DE405/LE405.
Design/methodology/approach
Each mission scenario is parameterized with different values of departure date and spacecraft characteristic acceleration, the latter representing the maximum propulsive acceleration when the Sun–spacecraft distance is 1 au. The transfer trajectories are studied in an optimal framework, using a Gauss pseudospectral method in which the initial guesses for the state and control histories are obtained with a genetic algorithm-based approach.
Findings
The paper illustrates the numerical simulations obtained with a spacecraft characteristic acceleration of 1 mm/s2, and the results cover a range of launch dates of 17 years for both Earth–Mars and Earth–Venus interplanetary missions. In particular, the numerical results confirm the competitiveness of such a propellantless propulsion system.
Practical implications
A parametric study of the transfer’s flight time corresponding to the optimal departure dates is discussed for different values of the spacecraft characteristic acceleration. The results motivate a further in-depth analysis of the E-sail concept.
Originality/value
This paper extends previous work on optimal trajectories with an E-sail in that the best launch opportunities are investigated. A refined thrust model is also used in all numerical simulations.
Details
Keywords
Linbo Yang, Joo Seng Tan and Chenjing Gan
Rapidly changing technological and marketing environments challenge the survival of business organizations. Developing dynamic capability is critical in helping companies respond…
Abstract
Purpose
Rapidly changing technological and marketing environments challenge the survival of business organizations. Developing dynamic capability is critical in helping companies respond to today's turbulent environments. Thus, fruitful studies on the antecedents of dynamic capability have been conducted. However, in the context of the supply chain, little is known about the factors that can be harmful to dynamic capability. Drawing on the theory of cooperation and competition, the first purpose of this study is to examine the relationship between independent goal interdependence with suppliers and dynamic capability by focusing on the mediating role of supplier integration. Combining the information processing theory and transaction cost economics with the theory of cooperation and competition, the second purpose of this study is to discuss and test the moderating role of internal integration.
Design/methodology/approach
Using a carefully designed questionnaire, a large-scale survey was employed to collect data in China. The senior manager (e.g. president, vice president, chief executive officer [CEO], executive or purchasing manager) of each company was asked to participate in our survey. The final valid sample in our survey consisted of 233 companies. Hierarchical multiple regression statistical analysis and bias-corrected bootstrapping methods were applied to test the correlation, mediation, moderation and moderated mediation relationships between variables.
Findings
The authors found that independent goal interdependence negatively influences dynamic capability through frustrating supplier integration. In addition, the moderated mediation model analysis shows that internal integration weakens the positive direct effect of supplier integration on dynamic capability while neutralizing the negative indirect effect of independent goal interdependence on dynamic capability. The theoretical and managerial implications of these results are discussed.
Originality/value
First, starting from the goal interdependence and supply chain management perspectives, this research not only is consistent with remote theoretical research that explains why interdependence among organizations influences the capability to enhance competitive advantage but also incorporates relevant internal and external factors that influence dynamic capability. Second, by proposing an innovative boundary factor – internal integration – this study also contributes to adjusting the predictions of the theory of cooperation and competition. Third, focusing specifically on the negative antecedent of dynamic capability can provide a better understanding of the antecedents that cause companies to have weakened dynamic capability.