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We present work related to designing a communication network for lunar exploration. We discuss the important requirements for future space missions that influence the design of this network. We list some characteristics of the network, and highlight important issues and constraints related to performance, cost, and future network evolution. We address issues related to efficiency, fairness, end-to-end delay minimization and Quality-of-Service (QoS) framework in order to enable a flexible access and dynamic mission operation. To provide optimal or near-optimal efficient utilization and fair allocation of bandwidth of the downlink channel while guaranteeing specific QoS requirements for different service classes, we propose two-level (long-term static and short-term dynamic) sharing of a slotted high data rate satellite communication link. The long-term optimal bandwidth allocation is implemented to provide per-stream/per-user QoS guarantee and give the inputs to the next level, short-term dynamic bandwidth allocation. In our time-varying short-term bandwidth allocation with threshold regulation, a small portion of bandwidth is still assigned to all active spacecrafts in advance, but most bandwidth is dynamically allocated by the requests from them, per frame, by solving an optimal timeslot scheduling problem. I. Introduction HE new phase of space exploration involves a growing number of human and robotic missions with varying communication and service requirements. These will include continuous, maximum coverage of areas of concentrated activities, such as in the vicinity of in-space planetary outposts and orbiting missions (single spacecraft or constellations) around the Earth, Moon or Mars. These nodes would be connected back to Earth through a broadband backbone and relay infrastructure. This Space Information Highway would serve the dual role of providing virtual presence to space, mission telemetry and control and coordination between missions but also broadband capability to download collected data back to Earth. Several network topologies that involve a space component are possible. Most of the proposed topologies are for scientific interplanetary communication, with satellites acting as relays to connect remote networks on distant planets to networks on Earth. The resulting networks form hierarchical hybrid meshes and present interesting challenges to overcome the constraint of long propagation delay, ensure robustness against fluctuations in satellite channel conditions due to atmospheric changes, and to ensure secure communication between users. In this report we present work related to designing a communication network for lunar exploration. We discuss the important requirements for future space missions that influence the design of this network. We list some characteristics of the network, and highlight important issues and constraints related to performance, cost, and future network evolution. The proposed network can be considered as a prototype for future missions to the Moon and beyond. This network shares similarities with terrestrial wireless network and sensor network architectures. However, the issues related to performance, robustness and security are different due to the long delay over the inter-satellite links, the limited power of the space nodes, the special hardware required to support functionality in space, and very different conditions on the lunar surface. Therefore solutions that are geared towards terrestrial Copyright © 2006 by HyNet. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.

Flexible and Dynamic Communication Architecture for Lunar Exploration