Sharif Digital Repository

In the recent years, many universities invest on cubesats to prepare an appropriate environment for their students to get their hands on real experiments including design, fabrication, test, launch, operation and analysis of a real satellite project. Now after 5 years of experimentation, it is time for leaders to define more practical goals beside training students. Orienting the budget that is annually being invested on such satellites in every country to a specific goal could be a driving force in opening a new chapter in the utilization of pico-satellites and the advantages they offer. As these tiny satellites are utilized based on low cost COTS and also are light weight enough to reduce... 

This research is dedicated to show the possibility of using solar radiation pressure by solar sails for interplanetary flights. In this paper, in addition to the Introduction of solar sailing and physics of solar radiation pressure, the solar sail orbital dynamics for optimal trajectory of an ideal solar sail spacecraft has been studied. It considers the problem of optimal controlling the sail angle so as to execute a minimum-time coplanar orbit transfer from the circular initial orbit to the circular target orbit. The direct collocation optimal control technique is used to transform the state equations to a set of nonlinear algebraic constraint equations. The results of state and control... 

The vision of future space exploration includes missions to deep space that require communication among ground stations on ground and another planets such as mars, moons, satellites in different orbiters, asteroids, robotic spacecrafts, and specially for crewed vehicles for delivering information. These communications requires high bit rate for autonomous operations and also have several different limitations. These type of communications set as a network that is called Interplanetary Network (IPN). There are difference challenges in space communication that TCP and UDP are not able to address them such as Long propagation delay, asymmetric bandwidth, etc. In this work, a congestion method... 

Priodic orbits have been studied more extensively by space mission designers in recent years. These orbits are usually described as planar in three-body-problems. In this article, in addition to introducing a new orbit that turns around a secondary mass, applications in Moon-based, Earth-based, and interplanetary missions are also described. Floquet exponents as chaos indicators and normal potential levels for orbits are also calculated. The advantages of their use as space station orbits are studied at the end of the article