June 18, 2007: Last week, the U.S. launched a secret payload that was, apparently, two electronic monitoring satellites, to provide ocean surveillance, and a system for keeping track of suspicious ships, particularly those carrying weapons or terrorists, or both. All this cost about $700 million (the two birds and the Atlas 5 rocket). This project had been discussed openly for months, including the approximate date of the launch. But since it involved counter-terror and space based reconnaissance, it was officially a secret.

There are already other ocean surveillance satellites up there. But these birds wear out, and have to be replaced. Moreover, most of the satellites watching the ocean have a hard time tracking ships over a long period of time. The two new satellites are about a thousand kilometers up, and track ships by detecting their electronic emissions, and tracking the movement of those detection events. This work is critical if you care tracking some small merchant ship belonging to some outfit known to work with terrorist organizations. A ship could be undetected if it maintained electronic silence, but that is difficult to do.