A new federal law, signed by the president on [February 14], compels the Federal Aviation Administration to allow drones to be used for all sorts of commercial endeavors. Local police and emergency services will also be freer to send up their own drones. But while businesses, and drone manufacturers especially, are celebrating the opening of the skies to these unmanned aerial vehicles, the law raises new worries about how much detail the drones will capture about lives down below - and what will be done with that information. Some questions likely to come up: Can a drone flying over a house pick up heat from a lamp used to grow marijuana inside, or take pictures from outside someone's third-floor fire escape? Can images taken from a drone be sold to a third party, and how long can they be kept? The American Civil Liberties Union and other advocacy groups are calling for new protections against what the A.C.L.U. has said could be routine aerial surveillance of American life." The new law, part of a broader financing bill for the F.A.A., came after intense lobbying by drone makers and potential customers. These manufacturers have been awaiting lucrative new opportunities at home. The market for drones is valued at $5.9 billion and is expected to double in the next decade, according to industry figures. Drones can cost millions of dollars for the most sophisticated varieties to as little as $300 for one that can be piloted from an iPhone.