Microsatellites, spies in the sky
PEOPLE already worried about the candid cameras on Google Glass and low-flying drones can add a potential snooper to the list: cameras on inexpensive, low-orbiting microsatellites that will soon be sending back frequent, low-cost snapshots of most of Earth's populated regions from space.
Earth-imaging satellites the size of vans have long circled the globe, but those cost millions of dollars each to build and launch, in part because of their weight and specialised hardware.
The new satellites, with some of the same off-the-shelf miniaturised technology that has made smartphones and laptops so powerful, will be far less expensive.
Mr Paul Saffo, a forecaster and essayist, expects the new satellite services to find many customers.
Insurance companies, for example, could use the satellites' "before" and "after" views to monitor insured property and validate claims after a disaster.
Businesses that update online maps for geologists, city planners or disaster-relief officials could be customers, too. The images could also be used to monitor problems like deforestation, melting ice caps and overfishing.
But the images are also likely to be viewed by people already apprehensive of Big Brother-like surveillance in their lives as the latest mixed blessing.
First into space in the microsatellite business will be San Francisco company Planet Labs, which plans to launch a fleet of 28 small satellites at the end of the year that will photograph the planet round the clock, with frequent updates.
The company has already sent up two trial satellites, and will dispatch the entire set, called Flock-1, in December, said Mr Will Marshall, a co-founder of the company and a former Nasa scientist.
The Planet Labs' satellites won't be able to distinguish your face or read your licence plate - the cameras don't have that level of resolution.
But the frequency with which images can be updated could raise privacy questions, said Mr Timothy Edgar, a visiting fellow at the Watson Institute for International Studies at Brown University and a former director of privacy and civil liberties in the Obama administration.
Mr Edgar contrasted the satellite images with those provided by Google Earth - the ones that people zoom in on to see, for example, an aerial view of their homes.
"That's just an image of your house that was probably taken a few years ago," he said.
"It may feel like you are being watched, but you aren't. It's just a static picture that's most likely several years old."
But a satellite that passes regularly over your home and photographs a car that is sometimes parked there - and sometimes not - has different ramifications.
"It can show a pattern, for example, when you appear to be at home and when you're away," he said.
Journalism professor Mitchell Stephens - who wrote the book The Rise Of The Image, The Fall Of The Word - said the new satellites are yet another stage in the expansion of the human view aided by powerful cameras and digital communication.
This change has pluses and minuses, he added. People who try to build a private hideaway in the woods might come to realise that it isn't so private. But such images could also spot illegal logging in remote spots.
"Now we can have a God-like view, looking down from the heavens," he said.
"I can understand why people would be nervous. But the cameras can make the world more transparent and open. I'm for that."