Robie Samanta Roy

• Doctor of Philosophy
• COO at Electra.aero

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1991. Includes bibliographical references (p. 194-196). by Robie I. Samanta Roy. M.S.

This Congressional Budget Office (CBO) study - prepared at the request of the Subcommittee on Emerging Threats and Capabilities of the Senate Armed Services Committee - looks at technical, operational, and cost issues related to using a boost-phase intercept (BPI) system to defend the United States against intercontinental ballistic missiles. The s...

A conceptual framework of the nature, structure, and dynamics of technological innovation is developed and applied to the small satellite industry. Important components of this framework include: the speed and acceleration of technological innovation; and the linear and nonlinear interactions between technology producers and users. The technology d...

In this paper, the authors develop a conceptual outline of the nature, structure and dynamics of technological innovation and in particular, its speed and acceleration, and then try to identify links between their conceptual outline and empirical corroborating evidence in the small satellite manufacturing sector in both the US and international mar...

In this paper, the authors study the nature, structure and dynamics of technological innovation and in particular, its speed and acceleration, in the small satellite manufacturing sector in both US and international markets. They focus on the technological, financial and regulatory factors that affect the process of technology development and comme...

The authors and 50 other students from around the world participated in the International Space University's (ISU) 1996 Summer Session Solar Probe Design Project. The main product of this was a 349-page text on the future of solar exploration and applications entitled Ra: The Sun for Science and Humanity. This article condenses and highlights the p...

A fully three-dimensional hybrid plasma particle-in-cell model for multi-computer environments was developed to assess the spacecraft backflow contamination of an ion thruster. Results of plume backflow are presented for a 13-cm xenon ion thruster operating with a current level of 0.4 A on a model spacecraft. The computational domain was over 40 m3...

The plume structure and the backflow of both propellant and sputtered grid material from two 8-cm xenon ion thrusters operating simultaneously were investigated with a three-dimensional model of an ion-thruster plume based on the plasma particle-in-cell technique. Thruster center to center separation distances of 10 and 17 cm were examined. The sep...

An axisymmetric model of the plume and backflow contamination from an ion-thruster plume is presented. Components included are primary beam ions, neutral propellent efflux, thermal propellant ions created mainly by charge-exchange collisions between primary beam ions and neutral propellant, nonpropellant efflux sputtered from thruster components, a...

A two-dimensional axisymmetric model was developed to investigate the plasma environment induced by an ion thruster and to assess plume backflow contamination. Predictions of the propellant charge-exchange plasma and sputtered molybdenum-grid metal effluents from the NASA 30-cm xenon ion thruster over a wide range of operating conditions during spa...

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1995. Includes bibliographical references (p. 237-246). by Robie I. Samanta Roy. Ph.D.

While the potential problems of spacecraft contamination by the effluents of electric propulsion thrusters have been known for some time, the limitations of ground experiments, and until recently, computational power, have prevented accurate assessments and predictions of spacecraft contamination. We are developing a hybrid plasma particle-in-cell...

form only given. The authors have developed a 2-D electrostatic hybrid plasma particle-in-cell code with a Monte Carlo collision operator to simulate the transport of ions in the plume of an ion thruster. The electron density, velocity, and temperature are computed by solving the electron continuity, momentum, and energy equations. All ions move un...

Tethers in space can be used for a wide variety of applications such as power generation, propulsion, remote atmospheric sensing, momentum transfer for orbital maneuvers, micro-gravity experimentation, and artificial gravity generation. These are only a few of the host of uses that have been envisioned and proposed for many years. In general, a tet...

An existing anisotropic anodic plasma contactor model is extended to include neutral gas emissions. Within the framework of the contactor model, the inclusion of external ionization leads to an integro-differential equation. By choosing the ratio of the contactor radius (a0) to the neutral gas-electron ionization mean free path at the contactor exi...

The potential problems of spacecraft contamination by the effluents of electric propulsion thrusters have been known for some time. Today, advanced plasma thrusters are being developed utilizing novel propellants such as C60 for ion thrusters, and alkali metals for magnetoplasmadynamic thrusters. In order to realize the full potential of these thru...

An existing anisotropic anodic plasma contactor model is extended to include neutral gas emissions. Within the framework of the contactor model, the inclusion of external ionization leads to an integrodifferential equation. By choosing the ratio of the contactor radius to the neutral gas-electron ionization mean free path at the contactor exit as a...