Among the US government's most closely guarded secrets, the quality of pictures NGA receives from classified satellites is believed to far exceed the one-meter resolution available commercially. That means they can take a satellite "snapshot" from high above the atmosphere that is crisply detailed down to one meter level, which is 3.3 feet.

Clapper says his agency only does big pictures, so concerns about using the NGA's foreign intelligence apparatus at home doesn't apply.

"We are not trying to examine an individual dwelling, for example, because what our mission is normally going to be is looking at large areas," he said. "It doesn't really affect or threaten anyone's privacy or civil liberties when you are looking at a large collective area."

When asked what additional powers he'd ask Congress for, he said, "I wouldn't."

His agency also handles its historic mission: regional threats, such as Iran and North Korea; terrorist hideouts; and tracking drug trade. "Everything and everybody has to be some place," he said.

He considers his brand of intelligence a chess match. "There are sophisticated nation states that have a good understanding of our surveillance capabilities," including Iran, he said. "What we have to do is counter that" by taking advantage of anomalies or sending spy planes and satellites over more frequently.

Adversaries who hide their most important facilities underground is a trend the agency has to work at, he said.

NGA was once a stepchild of the intelligence community. But Clapper said it has come into its own and become an equal partner with the other spy agencies, such as the CIA.

Experience-wise, the agency is among the youngest of the spy agencies. About 40 percent of the agency's analyst have been hired in the last five years.

"They are very inexperienced, and that's just fine. They don't have any baggage," said Clapper, who retires next month as the longest serving agency director. "The people that we are getting now are bright, computer literate. ... That is not something I lie awake and worry about."