Architecture Technology Corporation (ATC) will design, model, implement, and demonstrate extensible, embedded agents that will continuously adapt the behavior of the Internet-standard Transmission Control Protocol (TCP) to the unique requirements of near-Earth space communications. These embedded agents will enable TCP to adapt its behavior based on exogenous information, such as satellite ephemeris and ground station locations, or the current characteristics of the communications path as determined by lower-level protocols or periodic end-to-end tests. By extending the transport protocol, this approach will improve near-Earth communications for all higher-level protocols that use TCP, such as FTP or HTTP, and will eliminate the need to modify these applications for space communications. Initially, embedded TCP agents will enable TCP to maintain sessions, transparently to applications, across temporary losses of communications, such as when a satellite passes between ground stations. Embedded agents can easily be extended to mitigate other effects of near-Earth communications, such as variable latencies or bit error rates. While TCP has been widely researched, modeled, and extended, embedded TCP agents are unique in providing an extensible, production-quality platform for quickly integrating cutting-edge research results into products that will support the unique needs of near-Earth space communications and other demanding communications environments.