In January 2001, a commission headed by then US Defense Secretary-designate Donald Rumsfeld warned about a possible “space Pearl Harbor” in which a potential enemy would launch a surprise attack against US-based military space assets, disabling them. These assets include communications satellites and the GPS system, which is crucial for precision attack missiles and a host of military systems.
“The US is more dependent on space than any other nation. Yet the threat to the US and its allies in and from space does not command the attention it merits,” the commission warned.
One of the systems that grew out of the commission’s report was the Space Based Space Surveillance (SBSS) project, which is developing a constellation of satellites to provide the US military with space situational awareness using visible sensors. After a slow start, SBSS Block 10 reached a significant milestone in August 2012 with its Initial Operational Capability.