www.ll.mit.edu Tech Notes Extended Since the first manmade satellites orbited the earth in the 1950s, space Extended Space Sensors Architecture (ESSA) project is an Advanced Concept Space Sensors assets have become essential to national security. Satellites provide communica- Technology Demonstration to explore the issues, highlight the benefits, and Architecture tions and navigation for military per- sonnel. Naval strategists use satellite demonstrate the use of a service- oriented architecture (SOA) in support surveillance data to monitor ship move- ments, while meteorologists gather In an SOA, data and service Lincoln Laboratory is information relayed from space to track providers “register” their offerings weather patterns. Both manned and demonstrating a service- unmanned exploration flights contrib- in common online registries. Users in need of data or processing oriented network architecture ute to military scientists’ understanding can perform a web search to find of space. To protect these assets from that enables the space both natural and manmade harm, the appropriate data and services. community to share United States first has to have an accu- information and services rate picture of everything in space and of space missions. In an SOA, data what it is doing—i.e., space situational and service providers “register” their from the varied systems of the awareness. offerings in common online registries. Space Surveillance Network. MIT Lincoln Laboratory is working Users in need of data or processing can to provide an information technol- perform a web search to find appropri- ogy structure to enable access to and ate data and services. By visiting the distribution of space situational aware- referenced website, users obtain full ness data to the space community. Its instructions for how to automatically Register data 1 and services Data and Service Registries Data and Service Providers Search and Deploy data and discover data processing services and services 2 Request Response Access data For further information, contact: and services Data and Service Servers Communications Office Consumers MIT Lincoln Laboratory 244 Wood Street Service-oriented architectures make data and services readily available to both antici- Lexington, MA 02420-9108 pated and unanticipated users by allowing providers (1) to register and post information 781-981-4204 and services that consumers (2) can search for and then access. request information or processing and outside the conventional space com- In the ESSA SOA, Lincoln Labora- a description of what exactly will be munity, as well as among the various tory has attached auxiliary comput- returned. Users can then configure their mission areas within the space com- ers (referred to as sidecars) to three systems to access and use this informa- munity, resulting in the underutiliza- operational Space Surveillance Net- tion or processing. The loose coupling tion of data. Furthermore, this network work radars in the continental United between providers and users, and the infrastructure can prevent utilization States and the Marshall Islands, and use of registries to advertise and dis- of space information in other mission has deployed three more sidecars— cover capabilities, greatly facilitates areas. The existing architecture also one to an operational optical site in integration of new value-added pro- impedes development and deployment New Mexico, another to a space assets cessing and services to the SOA. of new capabilities by making it dif- ground station in Colorado, and a third The need for a structure such as ficult not only to access and distribute to a DoD radar in Hawaii. The system ESSA is driven by the fact that the information, but also to integrate data in Hawaii is included to demonstrate information technology infrastructure and processing into the current, some- cross-mission asset interoperability. for the United States’ array of sensors times proprietary, system. New data from any of these sys- tems are published to one of the NCES messaging channels. Data are also Since users do not necessarily know when data will be available, and hence archived by these sidecars and are when to request it, a “pub-sub” (publish and subscribe) messaging service searchable and retrievable by users that publishes all new information to one of many “channels” to which users after the fact. The Laboratory has simi- can subscribe is highly valuable. larly tapped two processing facilities: the Space Defense Operations Center, which publishes high-level space situ- is still largely based in early 1980s tech- The ESSA concept makes all ational awareness information such nology. This infrastructure adequately domain-specific services available, but as satellite launch, decay, maneuver, accommodated space surveillance several common “core” services are and orbital element sets information; when it was simply concerned with also needed by all to make an SOA and the Lexington Space Situational tracking and cataloguing a small popu- interoperable. In particular, since users Awareness Center (LSSAC) in Mas- lation of satellites. During the 1950s do not necessarily know when data will sachusetts. The LSSAC hosts a number and 1960s, satellites were launched be available, and hence when to request of services that can be used by clients infrequently and had limited capabili- it, a “pub-sub” (publish and subscribe) in the SOA, including satellite status, ties. However, over the years, as many messaging service that publishes all satellite viewing, threat assessment, countries established their presence in new information to one of many “chan- and conjunction predictions (satellite space, the space population grew to nels” to which users can subscribe is close approaches), and change detec- tens of thousands of objects, ranging highly valuable. All of these interac- tion information. All channels and ser- from large payloads to microsatellites tions must also be secure to protect vices are protected via NCES security. to debris. In response, the United States Department of Defense (DoD) informa- The ESSA effort is demonstrating developed and deployed an array of tion. To enable network interoperability, the ability to deliver space situational sensors—radar and optical—to find, a common security service is essential awareness information and capabili- track, categorize, catalogue, and assess for avoiding the problem of different ties that were not previously available the status of satellites; yet, the technol- usernames, passwords, and policies for to the space community or to other ogy used to distribute and integrate different websites/services. DoD users. It is likewise illuminating these sensors’ data lagged behind. The Defense Information Security networking infrastructure, core service, Currently, the data produced by the Agency has initiated the Net-Centric and policy and procedure issues that Space Surveillance Network are largely Enterprise Services (NCES) program to will need to be addressed in the future routed point-to-point, hub and spoke, provide the DoD with pub-sub, secu- to support operational SOAs. with bandwidths less than those of rity, and other common services, as well today’s home Internet dial-up services. as data, service, and user registries with This structure limits access by users which to instantiate SOAs. Opinions, interpretations, and recommendations herein are not necessarily endorsed by Lincoln Laboratory’s government sponsors. Work described in this document is performed under the prime contract with the U.S. Air Force, FA8721-05-C-0002.