Broadband communication support for earth observation from the International Space Station

In order to support the communications needs of Earth-observing instruments on the International Space Station (ISS), alternative communications architectures to provide broadband support need to be considered. In this paper, we evaluate the direct-to-ground option in terms of coverage. We show that a direct-to-ground option is a feasible solution to enhance the limited communication capabilities provided from the current ISS infrastructure. In order to ensure efficient end-to-end communication support and deal with the complications of the space environment, COTS (Commercial, Off The Shelf) equipment with recently demonstrated protocol modifications need to be adopted. We also demonstrate that selecting the most appropriate location for placement of the ground stations is an important design issue that can ensure optimal coverage and maximize throughput. As both the need for broadband services from the ISS and from other upcoming space-missions increases, this option will play a role in enhancing the currently limited space-relay architecture until a next generation relay system is deployed. 2004 Elsevier B.V. All rights reserved.