Journal of Technology in Aerospace Engineering
Year:2020 | Volume:2 | Issue:4 (11)|Papers Count:7

Spacecrafts, such as artificial satellites and space probes have small rockets called thrusters for orbital maneuvering, and satellite attitude control. These thrusters produce thrust by exhausting gases from their nozzles. On the other hand, reduction of propellant consumption, operability improvement/safer handling, and cost reduction are required for thrusters used. For this reason, reactive control systems use new propellants (green propellants) rather than toxic propellants. Various types of green propellants have been produced, which have not been used for various reasons, such as: low storability, low ISP, and low density. However, operational characteristics of some types of green propellants are suitable to use. Hydrogen Peroxide, Nitrous Oxide, Hydroxyl Ammonium Nitrate, Hydrazine Nitroformate, and Ammonium Dinitramide are green propellants that are approved by many organizations and are beeing used in space thrusters. With a brief overview of types of thrusters, this article compares different green propellants and suggests the best option.

The purpose of this paper is to investigate the magnetohydrodynamics technology in creating artificial earthquakes. For this purpose, the possibility of expressing the electronegative mechanism for artificial earthquakes is first discussed. Then, the mechanism of such earthquakes and their impact, using this technology has been investigated. Also, application of these artificial earthquakes is described. As follows, using field and laboratory experiments, the results of tectonic tensions with high power pulses to reduce earthquake hazards have been addressed. Subsequently, the description of this technology and its mechanism and further the measurement of the tectonic stresses of the earth's crust and its evacuation, using a magnetohydrodynamic high power generator, have been made. Finally, an example of the creation of an artificial earthquake is mentioned and examined.

This article study how to implement FRTO Module of ASBU Master Plan (the latest and most recent ICAO aviation document) to help meet the future needs of aeronautical industry and to increase operational capacity with the aim of increasing safety, cost-effectiveness, and airways capacity. The purpose of this module is to optimally use the airspace of the Islamic Republic of Iran and the Middle East region. Therefore, in the second part of this study, the navigational infrastructure required is described and the steps for the implementation of this module from the perspective of PBN in Tehran's TMA have been investigated.

consideration of its dynamics and modeling of an air-breathing propulsion system, using its velocity feedback. To this end, the dynamic equations of the vehicle and mathematical model of the air-breathing propulsion system are derived. Then, the non-linear dynamic equations of the vehicle and the equations of the propulsion system are combined. By presenting dynamic equations in state space, the linear optimal control formulation with dynamic constraint equations and minimum energy cost function is developed. By solving this optimal control problem, variant simulations are performed. Note, considering different initial conditions and ancertainity, the system's optimal control has been implemented fairly well. Moreover, the weighting coefficients of the optimal control problem considerably affect the optimal path and energy consumption. The obtained results indicate the applicability of the proposed method for modeling and control of the aerial vehicle with an air-breathing propulsion system.

In recent years, use of non-metric imaging sensors is becoming increasingly common in unmanned vehicles. This can be considered as an alternative to terrestrial mapping. Due to the limitations such as dimension, system weight, and the nature of UAV platform, it is not possible to use high volume and heavy metric sensors. Consequently, most sensors used in UAV platforms are light weight non-metric cameras. Determining the values of the internal parameters of the sensor is important in monitoring the variations of these sensors and improving the triangulation results of these images. Therefore, laboratory geometric calibration for these sensors under similar operating conditions produces better results in later stages. Our station is capable of performing calibration observations and also the calculations of a wide range of non-metric cameras and is currently serving in related organizations with ability to evaluate the accuracy of calibration results.

Plant study in space under microgravity condition is a very important goal in sending alive animals and human beings to space. Gravity modulates plant growth and its development and these processes are influenced by the balance between cell proliferation and differentiation in meristems. Regulation of cell cycle progression causes cell proliferation and growth and finally produces optimum biomass. Microgravity affects cellular processes and compounds. Plant growth and development changes under such condition, leading to alterations in the cytoplasmic membrane, transcriptome, proteome, cell wall, and Ca2+-signaling in specialized and not specialized cells of gravity perception. Cellular and molecular studies can help to visualize response mechanisms to microgravity and the solution of problems in plant culture in space.