U.S. warns of threat to satellites:
"A number of countries are exploring and acquiring capabilities to counter, attack, and defeat U.S. space systems," Joseph said
He also said terrorists "understand our vulnerabilities and have targeted our economy in the past, as they did on 9/11." He said terrorists and enemy states might view the U.S. space program as "a highly lucrative target," while sophisticated technologies could improve their ability to interfere with U.S. space systems and services.
Joseph did not identify terror groups or nations that might have such motives. An aide to Joseph, who spoke on condition of anonymity because he was not authorized to discuss the matter, said that information was classified.