surveillance drones

While most research directed at improving UAVs focuses on upgrading their weapons or sensor packages, the Naval Research Laboratory is also working to ensure that the next generation of killer drones are as fuel-efficient as they are deadly. And a recent test of their hydrogen-fuel-cell-powered Ion Tiger UAV proves how successful they have been: it staid aloft for just shy of 24 hours on a single fuel load.

Two years ago we wrote about Norwegian engineer Petter Muren's effort to build a mini copter weighing only 3.3 grams. that radio-controlled craft, the Picoflyer, could take off from the palm of your hand. Now Muren has designed the larger but more capable Black Hornet.

To security experts, the immense cargo ships that ferry more than 11 million containers into this country annually are potential Trojan horses-each one could easily harbor a WMD, such as a dirty bomb. Typically, only once the ships have been unloaded is their cargo subjected to random inspections and radiation scans. "There is an urgent need to effectively screen cargo before it reaches the ports," says Charles Meade, a senior scientist at the RAND Corporation, a nonprofit think tank.