The Space Communications Protocol Standards (SCPS) specify a developmental system of international protocols for data communications between spacecraft and points on Earth. SCPS protocols are intended to make a spacecraft appear, to a terrestrial computer user, as just another node on the Internet. The protocols are implemented to be as interoperable as possible to other systems. The SCPS file protocols are based partly on the Internet File Transfer Protocol (FTP), but include additional features necessary for smooth communication over channels that include interruptible Earth/spacecraft links; unlike the Internet FTP, the SCPS protocols provide for restart of interrupted file transfers and provide record read/update services. The SCPS protocols include (1) a file-handling protocol based on the Internet FTP, with modifications to optimize performance for typical spacecraft data streams; (2) an underlying retransmission protocol based on the Internet Transmission Control Protocol (TCP), with modifications to ensure reliability in the face of interruptions; (3) a data-protection protocol derived from a number of security protocols; and (4) a scalable networking protocol for routing of messages, based on the Internet Protocol (IP), with modifications to support space routing and increase communication efficiency.
This program was written by Eric Travis, Robert Durst, Patrick Feighery, and Mary Jo Zukoski of Mitre Corp. and by Steven Sides of SAIC for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Software category.
This software is available for commercial licensing. Please contact Don Hart of the California Institute of Technology at (818) 393-3425. Refer to NPO-20282.
This Brief includes a Technical Support Package (TSP).
Software for Spacecraft/Ground Communication via the Internet
(reference NPO-20282) is currently available for download from the TSP library.
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Overview
The document outlines the Space Communications Protocol Standards (SCPS), a suite of protocols developed to facilitate data communications between spacecraft and Earth-based systems, making spacecraft appear as nodes on the Internet. This initiative is a collaborative effort between NASA and the Department of Defense, aimed at creating interoperable standards that can be progressed towards full ISO standards through the Consultative Committee for Space Data Systems.
The SCPS includes several key components:
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SCPS File Protocol (SCPS-FP): This protocol is optimized for uploading spacecraft commands and software, as well as downloading telemetry data. It is based on the Internet File Transfer Protocol (FTP) but includes enhancements to handle the unique challenges of space communication, such as the ability to restart interrupted file transfers and provide record read/update services.
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SCPS Transport Protocol (SCPS-TP): This underlying retransmission control protocol is designed to ensure reliable end-to-end delivery of messages, even over potentially unreliable space data transmission paths. It is based on the Internet Transmission Control Protocol (TCP) and modified to meet the specific needs of space communication.
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SCPS Security Protocol (SCPS-SP): This protocol provides end-to-end security and integrity for message exchanges, drawing from various established security protocols, including the Secure Data Network Security Protocol and Internet Protocol Security standards.
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SCPS Network Protocol (SCPS-NP): This scalable networking protocol supports both connectionless and connection-oriented routing of messages through networks that include space data links. It is based on the Internet Protocol (IP) with modifications to enhance communication efficiency in space environments.
The document emphasizes the performance of the SCPS protocols, noting that they can operate effectively on small spacecraft and achieve transfer rates exceeding 95% of their commercial counterparts. The software developed under these protocols has been tested for interoperability with existing systems, ensuring that it can integrate smoothly into current communication infrastructures.
Additionally, the document mentions that the software is available for commercial licensing, providing opportunities for broader application beyond NASA's immediate needs. The development team includes experts from various organizations, highlighting the collaborative nature of this project.
Overall, the SCPS represents a significant advancement in space communication technology, addressing the unique challenges posed by the space environment while maintaining compatibility with terrestrial systems.
