The Deep Impact Network Experiment Operations Center

Delay/Disruption Tolerant Networking (DTN) promises solutions in solving space communications challenges arising from disconnections as orbiters lose line-of-sight with landers, long propagation delays over interplanetary links, and other phenomena. DTN has been identified as the basis for the future NASA space communications network backbone, and international standardization is progressing through both the Consultative Committee for Space Data Systems (CCSDS) and the Internet Engineering Task Force (IETF). JPL has developed an implementation of the DTN architecture, called the Interplanetary Overlay Network (ION). ION is specifically implemented for space use, including design for use in a real-time operating system environment and high processing efficiency. In order to raise the Technology Readiness Level of ION, the first deep space flight demonstration of DTN was performed using the Deep Impact (DI) spacecraft. Called the Deep Impact Network (DINET), operations occurred during Autumn 2008. An essential component of the DINET project was the Experiment Operations Center (EOC), which generated and received experiment communications traffic as well as “out-of-DTN band” command and control traffic, archived DTN flight test information in a database, provided display systems for monitoring DTN operations status and statistics (e.g., bundle throughput), and supported query and analyses of the data collected. This paper describes the DINET EOC and its value in the DTN flight experiment and potential for further DTN testing. The DINET EOC housed ground nodes that produced and consumed “payload” data that was relayed through the DTN router on board the DI spacecraft. The EOC also controlled the topology among the nodes, altering the connectivity to test DTN functionality. An additional node in the EOC acted to perform administrative functions, and contained the Monitor and Control System to view experiment health and concurrently collect and analyze the data delivery status and statistics. The software diagnostic messages and protocol diagnostic messages issued by network nodes were collected analyzed and stored into a database in real-time. The DINET EOC was located within the JPL Protocol Technology Lab (PTL). The PTL provides connectivity to other NASA centers and external entities, and is itself a node in the larger DTN Experiment Network (DEN). The DINET EOC is envisioned to become a general tool in this broader context of experimental testing of DTN across a geographically dispersed user community.