International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / The current challenge has been to develop and adapt commercial Internet protocols for usage in space communications. Commercialized solutions, rather than Customized ones are cheaper, have low turnaround time and offer higher flexibility in deployment and operation. The focus of the study was to modify and develop UDP/IP based protocols commonly used in commercial Internet for reliable data transfers in space environment. Multicast Dissemination Protocol was designed by Naval Research Laboratory to provide reliable multicast data and file transfer delivery on the top of general UDP/IP platform. It is very suited for bulk data transfer over the Internet. We have extended its usage in space channels and evaluated it as a solution to meet key challenges in space communications like high bit error rates and asymmetric channels. We have also tried to optimize the performance of the protocol in the terms of throughput, reliability, integrity and security of data. The evaluation test were carried on our Space to Ground Link Simulator which uses PPP to model point to point satellite links and correspond to low capacity systems as found in small satellite systems.

The thesis explores the role and impact of the internet on Sri Lankan Tamil diaspora political activism, focusing on both the experiences of political activists and on an analysis of web content related to diaspora activism. The central argument of the thesis is based around the relationship between political agents and cyberspace. The thesis argues that the political strategies and tactics adopted in the Tamil diasporan political sphere have changed with an increased dependence on the internet changing with it the politics and lives of individual activists. Cyberspace is presented as a site of power struggle with power as both an objective and source in micro-political struggles. The thesis also highlights the double sense of space attributed to cyberspace, both as a space facilitating political activism and as a qualitatively new space for politics. It traces the manifestation of violence in cyberspace based on its extensive reach and the collateral damage it can cause in political conflicts. Also the thesis argues that these intense web engagements for domination and resistance within the diaspora communities cause the emergence of new political priorities in Tamil diaspora politics. These do not parallel political developments in the conflict back in Sri Lanka. The thesis is based on research conducted from 2005 to 2008 during heightened rivalries between supporters of the LTTE (Liberation Tigers of Tamil Eelam) and dissident Tamil diaspora political activists which involved the extensive use of cyberspace for political purposes. The empirical research consisted of an integrated framework of online and offline research. The offline research was based on eight months of fieldwork in London including interviews with Tamil diaspora political activists across the spectrum from pro-LTTE to anti-LTTE dissidents. The online research was based on the technique of Web Sphere Analysis, which enables a framing of web content into a coherent unit of analysis.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / A large selection of hardware and software components are readily available for supporting Internet communication in the ground network environment. These components can be used to construct very powerful and flexible communication systems. The Operating Missions as Nodes on the Internet (OMNI) project at NASA/GSFC has been defining and demonstrating ways to use standard Internet technologies for future space communication. Theses concepts and technologies are also applicable to test range telemetry applications. This paper identifies the network equipment and protocols to support end-to-end IP communication from range sensors and spacecraft instruments to end users. After identifying the end-to-end network hardware and software components, the paper discusses which ones are currently available and lists specific examples of each. This includes examples of space missions currently using Internet technology for end-to-end communication. It also lists missing pieces and includes information on their current status. The goal of this paper is also to stimulate thought and discussion on what steps need to be taken to start filling in the remaining missing pieces for end-to-end range and space network connectivity.