Astrodynamics Commons^™

Autonomous Mission Planning For Spacecraft Rendezvous And Proximity Operations, Julia C. Bell

Theses and Dissertations

The evolving space environment has created a demand for autonomous spacecraft that can maneuver in complex and sometimes contentious environments. Constraint enforcement, such as an avoidance zone to prevent collision with a target, is a key component of autonomous control to ensure safety and performance requirements are met. Finite-horizon Model Predictive Control (MPC) is a popular control method due to its improved computation time while optimizing performance. Two areas of MPC in need of expansion are time-varying constraints and phase transitions in multi-phase applications. In this work, MPC is employed to track the reference trajectory of a multi-phase satellite inspection …

Adaptive-Optimal Control Of Spacecraft Near Asteroids, Madhur Tiwari

Doctoral Dissertations and Master's Theses

Spacecraft dynamics and control in the vicinity of an asteroid is a challenging and exciting problem. Currently, trajectory tracking near asteroid requires extensive knowledge about the asteroid and constant human intervention to successfully plan and execute proximity operation. This work aims to reduce human dependency of these missions from a guidance and controls perspective. In this work, adaptive control and model predictive control are implemented to generating and tracking obstacle avoidance trajectories in asteroid’s vicinity.

Specifically, direct adaptive control derived from simple adaptive control is designed with e modification to track user-generated trajectories in the presence of unknown system and …

Passive Disposal Of Launch Vehicle Stages In Geostationary Transfer Orbits Leveraging Small Satellite Technologies, Marc Alexander Galles

Master's Theses

Once a satellite has completed its operational period, it must be removed responsibly in order to reduce the risk of impacting other missions. Geostationary Transfer Orbits (GTOs) offer unique challenges when considering disposal of spacecraft, as high eccentricity and orbital energy give rise to unique challenges for spacecraft designers. By leveraging small satellite research and integration techniques, a deployable drag sail module was analyzed that can shorten the expected orbit time of launch vehicle stages in GTO. A tool was developed to efficiently model spacecraft trajectories over long periods of time, which allowed for analysis of an object’s expected lifetime …

Issue 4: Contributors, W.M. (Mac) Evans

Online Journal of Space Communication

The material in this issue has been developed and supplied by Telesat, the Communications Research Centre, and the Canadian Space Agency - the major players in Satellite Communications in Canada.

The Role Of Partnerships Government/Industry/International, W.M. (Mac) Evans

Online Journal of Space Communication

Much of Canada's involvement in space activities, particularly in the earlier years, related to its interest in satellite communications as a means to provide equitable access by all Canadians to telecommunications services. It also provided the impetus for Canada signing a cooperative agreement with ESA. There are a number of firsts in satellite communications to which Canada can lay claim. However the environment for space communications systems and services has changed dramatically and continues to change due to factors such as global deregulation, rapid advance of telecommunications technology, industrial consolidation and intense competition.

Market Analysis, W.M. (Mac) Evans

Online Journal of Space Communication

Canadian space companies have developed impressive and globally competitive competencies in some niche areas of satellite communications. This has allowed them to be very successful in domestic and export markets. In fact, 63% of total 2000 revenues of $1.4 billion were from Telecommunications. Satellite communications can be considered the cornerstone of the Canadian space industry at large.

Industry Capabilities And Services, W.M. (Mac) Evans

Online Journal of Space Communication

Space Communication technologies have provided the world with satellite communications and global satellite navigation infrastructures that have become strategic assets for the economic, political, and military sectors of countries around the world. Their omnipresence in our everyday lives and their significant role in world commerce, security and humanitarian operations such as Search and Rescue have made telecommunications and global navigation satellites indispensable.

Canada: Innovation And Inclusion In The Network Age, Michael Binder

Online Journal of Space Communication

Michael Binder, Assistant Deputy Minister Spectrum Information Technologies and Telecommunications Industry Canada

Paper based on a presentation given to the Canadian Satellite Users Association October 31, 2002

Ecanada = Equality Of Life; Fast Forward To Canadian Prosperity, Laurier J. Boisvert

Online Journal of Space Communication

Speaking notes for an address at the 17th Annual CATAAlliance Innovation and Leadership Awards Reception and Gala Smart City Summit April 23, 2002, Ottawa, Canada

Crc Perspective, Gerry Turcotte

Online Journal of Space Communication

Gerry Turcotte, President Communications Research Centre Canada

Internationacommunications Satellite Systems Conference Speaking Notes, Marc Garneau

Online Journal of Space Communication

Speaking notes at the plenary session of the International Communications Satellite Systems Conference Montreal, Canada

The Future Of Satcom In Canada: R & D Labs, Paul Bush

Online Journal of Space Communication

Recognizing the need to evaluate and test emerging technologies and applications, Telesat has recently made a significant additional investment to its existing R&D lab. The upgraded facility is a 4000 square-foot area dedicated to satellite-based broadband trials and demonstrations. The R&D Lab hosts active computing platforms that are networked over satellite and linked by a common theme of connecting Canada and Canadians. On-going trials are managed from a hub area and a network control centre within the Lab. The lab is designed to provide both a development environment and an educational and demonstration area.

The Future Of Satcom In Canada: New Technologies Needed, Virendra Jha

Online Journal of Space Communication

The Government of Canada has a clear goal of making Canada the most connected country in the world. The vast geographic topology and wide population distribution - some in remote communities - raise distinct technical and economic challenges in achieving this goal. In addition, communications are already used in virtually all space projects - either for the command of the Spacecraft, or as the raison d'être of the mission. Undoubtedly, to support the very nature of space projects and to achieve the goal of connecting all Canadians, ever-improved technologies are being sought.

The Future Of Satcom In Canada: Smart Communities, Paul Bush

Online Journal of Space Communication

Telesat has been a pioneer in the development of satellite-based smart communities

The Future Of Satcom In Canada: Schoolnet, Paul Bush

Online Journal of Space Communication

Telesat became involved in the Schoolnet I initiative by providing a satellite solution to facilitate Internet connectivity to approximately 1600 schools located in remote parts of Canada. Approximately 10% of the schools were connected under the Schoolnet I initiative.

The Future Of Satcom In Canada: New Applications/Services, Paul Bush

Online Journal of Space Communication

Telesat is the world's most experienced commercial fixed satellite operator, and a highly respected consultant and partner in satellite ventures around the globe. The Company competes with other top international satellite fleets in providing telecommunications and broadcasting services to more than 275 customers throughout the Americas. With over thirty years of engineering and technical experience, Telesat is a diversified, end-to-end satellite services company with some 500 employees stationed throughout the Americas and on international assignment.

Satcom Today In Canada: Significant Research: Broadband Satellite Communications List Of Citr Related Publications (1998-2003), W.M. (Mac) Evans

Online Journal of Space Communication

Journal Papers

Conference Papers

Contributions to Standards

Canadian Space Agency Recent Publications

Satcom Today In Canada: Significant Research: Overview Of The Cospas-Sarsat Satellite System For Search And Rescue, J. V. King

Online Journal of Space Communication

Cospas-Sarsat, an international satellite system for search and rescue, started operating in 1982 and has been credited with saving thousands of lives since then. Hundreds of thousands of aviators, mariners and land users worldwide are equipped with Cospas-Sarsat distress beacons, which could help save their lives in emergency situations anywhere in the world. This paper outlines the evolution of the system and describes how satellites are constantly circling the globe monitoring for ‘SOS signals’, while tracking stations on six continents receive the satellite signals, compute the locations of the distress events and forward the calls for help to the appropriate …

Satcom Today In Canada: Significant Research: Evolution Of Portable Ka-Band Terminals At Crc, Pierre Tardif

Online Journal of Space Communication

The Satellite Systems Research group (www.crc.ca/rss) of the Communications Research Centre Canada (CRC) conducts research and development on systems, concepts and technologies suitable for future generations of communication and navigation satellites. Over the past decade, R&D has been carried out in portable satellite terminals operating at Ka-Band frequencies (30/20 GHz). This paper presents the evolution and a chronological overview of the terminals’ development. The three generations of prototypes are presented.

Satcom Today In Canada: University Research Programs, Virendra Jha

Online Journal of Space Communication

In order to better support its overriding objective of the Canadian Space Program, which is "to develop and apply space science and technology in order to meet Canadian needs and develop an internationally competitive space industry," the CSA has created a grants and contributions program to support awareness, research and training in space science and technology.