Day-to-day routine orbital maintenance of two technology demonstration satellites has been transferred rapidly and inexpensively across the Atlantic from the United Kingdom to an American university, thanks to standards developed by an international program to which NASA was a major contributor.
The satellites, Space Technology Research Vehicle (STRV) 1a and 1b, were developed, built and are owned by the Defence Evaluation and Research Agency of the British Ministry of Defence. Responsibility for their routine maintenance has been delegated to the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder, CO.
The transfer was accomplished within four months at a cost of less than $200,000, said Adrian J. Hooke, acting manager of NASA's Space Operations Standards Program at the Jet Propulsion Laboratory (JPL), Pasadena, CA, which facilitated the effort.
"This transfer was accomplished quickly and inexpensively thanks to protocols that standardize the way spacecraft and ground systems talk to each other," said Hooke. "These new capabilities drastically lower the cost of integrating, testing and operating spacecraft."
Launched in 1994, the two STRV satellites carry an international suite of experiments studying the space environment near Earth. The satellites are in highly elliptical orbits that take them from 300 to 36,000 kilometers (185 to 22,300 miles) above Earth, passing through zones of high radiation. Data acquisition from the STRV spacecraft has been enhanced for much of their mission with tracking support from NASA's Deep Space Network.
Before the hand-off, the STRVs were used early in 1996 to flight-test a suite of new operations protocols currently in development that standardize file transfer, transport, security and network issues in the communications link between the satellites and ground. "In essence, the new way of communicating with spacecraft will look a lot like the Internet," said Hooke. "You will be able to transfer files to and from the spacecraft just as you do on the Internet using what is known as file transfer protocol (FTP) and the transmission control protocol (TCP)."
After operating the satellites for two years, the British Defence Research Agency this year needed to close its ground station at Lasham, England, for refurbishment in preparation for the planned 1999 launch of the next two STRVs. JPL suggested the operational transfer of the STRV satellites to the University of Colorado as a demonstration of the new international interoperability standards and as a way to both continue their scientific missions and also to use them as "flying testbeds" for new standards technologies.
Key among the protocols that eased the transition are new telemetry and telecommand interfaces between both spacecraft and ground systems that conform to standards developed by the international Consultative Committee for Space Data Systems.
"Packetized telemetry and telecommand standards are the underpinnings of all space missions from here on out," said Hooke. "You will see then on low Earth orbiters, planetary spacecraft like Cassini, the international Space Station -- they are becoming the universal way of communicating with spacecraft."
Hooke said that the effort marked the first time responsibility for routine orbital maintenance of satellites had been delegated across national borders to a university. The British Defense Research Agency retains full ownership and executive control of the STRV satellites and will determine their final disposition at the end of their lifetimes.
The cooperative effort -- which included the involvement of NASA Headquarters, the U.S. Air Force Space and Missile Systems Center and the U.S. Ballistic Missile Defense Organization -- also marks the beginning of a new era in which NASA and the U.S. Department of Defense hope to realize large cost savings by using strategic joint standardization in order to greatly increase the level of commonality and interoperability across the US civil and military space programs.
JPL manages the Space Operations Standards Program for NASA's Office of Space Flight, Washington, DC.
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