Every year, tens of billions of Pentagon dollars go missing. The money vanishes not because of fraud, waste or abuse, but because U.S. military planners have appropriated it to secretly develop advanced weapons and fund clandestine operations. Next year, this so-called black budget will be even larger than it was in the Cold War days of1987, when the leading black-budget watchdog, the Center for Strategic and Budgetary Assessments (CSBA), began gathering reliable estimates. The current total is staggering: $58 billion—enough to pay for two complete Manhattan Projects.

Where does the money go? Tracking the black budget has always been a challenge. Constantly shifting project names that seem to be randomly generated by computers—Tractor Cage, Tractor Card, Tractor Dirt, Tractor Hike and Tractor Hip are all real examples—make linking dollar amounts to technologies impossible for outsiders. But there are clues.

According to Todd Harrison, an analyst at the CSBA, the allocations for classified operations in the 2011 federal budget include $19.4 billion for research and development across all four branches of the military (funding for the CIA, including its drone strikes in Afghanistan and Pakistan, is contained within the Defense Department black budget), another $16.9 billion for procurement, and $14.6 billion for “operations and maintenance.” This latter category, Harrison notes, has been expanding quickly. This may suggest that many classified technologies are now moving from the laboratory to the battlefield.