Architectures for a Space-Based Information Network with Shared On-Orbit Processing by Serena Chan S.B. Computer Science and Engineering Massachusetts Institute of Technology, 1999 M.Eng. Electrical Engineering and Computer Science Massachusetts Institute of Technology, 2000 Submitted to the Engineering Systems Division in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Engineering Systems at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY February 2005 c 2005 Serena Chan. All rights reserved. The author hereby grants to MIT permission to reproduce and to distribute publicly paper and electronic copies of this thesis document in whole or in part. Author........................................................................................... Engineering Systems Division January 31, 2005 Certifiedby...................................................................................... Vincent W.S. Chan Professor of Electrical Engineering and Computer Science and Aeronautics and Astronautics Director, MIT Laboratory for Information and Decision Systems Thesis Supervisor Certifiedby...................................................................................... John Chapin Visiting Scientist MIT Laboratory for Information and Decision Systems Committee Member Certifiedby...................................................................................... L. Jean Camp Associate Professor of Public Policy John F. Kennedy School of Government Harvard University Committee Member Certifiedby...................................................................................... Daniel E. Hastings Professor of Aeronautics and Astronautics and Engineering Systems Director, MIT Engineering Systems Division Committee Member Accepted by...................................................................................... Richard de Neufville Professor of Engineering Systems Chair, Engineering Systems Division Education Committee 2 Architectures for a Space-Based Information Network with Shared On-Orbit Processing by Serena Chan Submitted to the Engineering Systems Division on January 31, 2005, in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Engineering Systems Abstract This dissertation provides a top level assessment of technology design choices for the archi- tecture of a space-based information network with shared on-orbit processing. Networking is an efficient method of sharing communications and lowering the cost of communications, providing better interoperability and data integration for multiple satellites. The current space communications architecture sets a critical limitation on the collection of raw data sent to the ground. By introducing powerful space-borne processing, compression of raw data can alleviate the need for expensive and expansive downlinks. Moreover, distribution of processed data directly from space sensors to the end-users may be more easily realized. A space-based information network backbone can act as the transport network for mis- sion satellites as well as enable the concept of decoupled, shared, and perhaps distributed space-borne processing for space-based assets. Optical crosslinks are the enabling technol- ogy for creating a cost-effective network capable of supporting high data rates. In this dissertation, the space-based network backbone is designed to meet a number of mission re- quirements by optimizing over constellation topologies under different traffic models. With high network capacity availability, space-borne processing can be accessible by any mis- sion satellite attached to the network. Space-borne processing capabilities can be enhanced with commercial processors that are tolerant of radiation and replenished periodically (as frequently as every two years). Additionally, innovative ways of using a space-based informa- tion network can revolutionize satellite communications and space missions. Applications include distributed computing in space, interoperable space communications, multiplatform distributed satellite communications, coherent distributed space sensing, multisensor data fusion, and restoration of disconnected global terrestrial networks after a disaster. Lastly, the consolidation of all the different communications assets into a horizontally integrated space-based network infrastructure calls for a space-based network backbone to be designed with a generic nature. A coherent infrastructure can satisfy the goals of interop- erability, flexibility, scalability, and allows the system to be evolutionary. This transforma- tional vision of a generic space-based information network allows for growth to accommodate civilian demands, lowers the price of entry for the commercial sector, and makes way for innovation to enhance and provide additional value to military systems. Thesis Supervisor: Vincent W.S. Chan Title: Professor of Electrical Engineering and Computer Science and Aeronautics and As- tronautics 3 Director, MIT Laboratory for Information and Decision Systems Committee Member: John Chapin Title: Visiting Scientist MIT Laboratory for Information and Decision Systems Committee Member: L. Jean Camp Title: Associate Professor of Public Policy John F. Kennedy School of Government Harvard University Committee Member: Daniel E. Hastings Title: Professor of Aeronautics and Astronautics and Engineering Systems Director, MIT Engineering Systems Division 4 Acknowledgments I wish to thank my advisor, Vincent W.S. Chan, for his patience, encouragement, inspira- tion, and assistance throughout my graduate studies. I also wish to thank the members of my doctoral committee, John Chapin, L. Jean Camp, and Daniel E. Hastings, for their comments, suggestions, and advice. I am grateful to my colleagues and friends at the Laboratory for Information and Decision Systems and the Engineering Systems Division for their friendship and care. Last, but not least, I wish to thank my husband, Abraham R. McAllister, and my family for their unwavering love, patience, and constant encouragement. This dissertation is based upon work supported by the National Reconnaissance Office. 5 6 Contents 1 Introduction 27 1.1 Military Satellite Communications . .................... 28 1.2Issues....................................... 30 1.3ThesisMotivation................................ 31 1.4Summary..................................... 35 2 Architectural Concepts and Enabling Technologies 37 2.1SpaceLaserCommunicationTechnology.................... 38 2.1.1 RadioFrequency(RF)vs.Optical................... 39 2.1.2 DesignRecommendations........................ 40 2.2DataProcessing................................. 40 2.2.1 Space-Based Processing vs. Ground-Based Processing . ...... 41 2.2.2 SpaceEnvironment............................ 42 2.2.2.1 TotalDoseEffects....................... 43 2.2.2.2 SingleEventEffects...................... 44 2.2.2.3 RadiationMitigationTechniques............... 44 2.2.2.4 Radiation-Hardened Processors vs. Commercial-Off-The- Shelf(COTS)Processors................... 46 2.2.3 DesignRecommendations........................ 48 2.2.3.1 Decoupled, Shared, and Distributed On-Orbit Processing . 49 2.2.3.2 LeveragingCOTSTechnology................ 50 2.3DataTransmission................................ 51 2.3.1 Analogvs.DigitalTransmission.................... 52 2.3.2 Analog-to-DigitalConverters...................... 53 7 2.3.3 DesignRecommendations........................ 54 2.4 Satellite Replacement and Replenishment Strategies ............. 54 2.4.1 On-Orbit Spare Satellites . .................... 55 2.4.2 Full Satellite Replacement . .................... 55 2.4.2.1 OriginalDesign........................ 55 2.4.2.2 UpdatedDesign........................ 56 2.4.3 On-OrbitServicing............................ 56 2.4.3.1 PotentialBenefitsofOn-OrbitServicing........... 56 2.4.4 DesignRecommendations........................ 57 2.5Summary..................................... 58 3 Network Architectures 61 3.1Space-BasedNetworkBackboneConstellation................. 63 3.1.1 OrbitSelection.............................. 63 3.1.1.1 GeostationaryOrbit...................... 64 3.1.2 ConstellationTopologies......................... 65 3.1.2.1 GraphTheoryNotationsandDefinitions.......... 66 3.1.2.2 ConnectedCirculantsConstellations............. 67 3.1.2.3 HubConstellations...................... 71 3.1.3 TrafficModelsandRouting....................... 72 3.1.3.1 UniformAll-to-AllTraffic................... 72 3.1.3.2 UniformAll-to-OneTraffic.................. 73 3.1.3.3 TrafficRouting......................... 73 3.1.4 CommunicationsCostModel...................... 74 3.1.4.1 AntennaCost......................... 74 3.1.4.2 SwitchCost.......................... 78 3.1.4.3 LinkCost............................ 79 3.1.5 CommunicationsCostModelingResults................ 79 3.1.5.1 ParameterValuesandCostValues.............. 80 3.1.5.2 Connected Circulant Constellations under Uniform All-to- AllTraffic............................ 82 3.1.5.3 Hub Constellations under Uniform All-to-One Traffic . 88 8 3.1.5.4 Hub Constellations under Uniform All-to-All Traffic . 90 3.1.5.5 Connected Circulant Constellations under Uniform All-to- OneTraffic........................... 91 3.1.5.6 MixedTraffic.......................... 111 3.1.5.7 Two Disjoint Communities of Users with Mixed Traffic . 124 3.1.6 LaunchCosts............................... 134 3.1.7 Discussion................................. 150 3.2NetworkedSharedOn-OrbitProcessing.................... 151 3.2.1 DataandImageCompressionApplications.............