Darius Farraye/CNET

Dramatic advances in satellite imaging technology in the last 10 years have privacy advocates worried about 24-hour surveillance. Right now, US regulations keep things in check. Commercial satellite imagery is powerful enough to see a car, for example, but isn't allowed to be detailed enough to identify the make and model, according to the MIT Technology Review. But innovations may soon skirt government rules.

Satellite companies say they keep a person's data separate from any identifying characteristics, but Peter Martinez of the space advocacy group Secure World Foundation said that doesn't matter.

"The risks arise not only from the satellite images themselves but the fusion of Earth observation data with other sources of data," Martinez said in an email.

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Then there's the sheer volume of satellites overhead. Imaging company Planet Labs confirmed that it has 140 imaging satellites currently in orbit. That's a significant chunk of the nearly 770 such satellites in total, according to MIT Technology Review. The report says that Planet Labs alone has enough satellites to pass over every place on Earth once a day.

"Even with Planet's highest resolution imagery (1m resolution), it remains impossible to distinguish individual people, car number plates, or otherwise identifying information. Our imagery is ideal for monitoring large-scale change on a daily basis. This includes seeing daily change across buildings and roads, forests, in agriculture, bodies of water and more," a spokesperson for Planet Labs said in an email.

The publication points out that the observational satellites can do good, too. They can help farmers monitor a crop's growth cycle, geologists better examine rock textures, and human rights organizations track refugee movement. And of course, other satellites do things like helping meteorologists predict the weather and making our phones and televisions work.

Charlie Loyd, an imagery specialist at online mapmaker Mapbox, said he comes across a lot of misperceptions about satellites.

"Most people I talk with actually overestimate how often and how clearly satellites photograph their neighborhood. Few places on Earth are seen from space at highest resolution more than once a month or so, and the clearest images are from airplanes, not satellites. We rarely talk about the privacy risks from airplanes, partly because most of us have a realistic sense of what they can do," Loyd said in an email.

Loyd said it's the responsibility of the Earth observation industry, which knows what satellites can do, to educate those who don't -- especially when it comes to easing unrealistic fears and starting conversations about real risks.

A licensing system and accountability do exist, he said. That falls under space law, as much as it might conjure up Star Trek in one's mind.

"There's a whole international and domestic legal framework around access to space, how orbital slots are divided up, how hardware should behave in space, and so on," Loyd said.

There's no sensor in orbit, or proposed for launch, that he considers worrisome. Loyd noted that, by themselves, the images are only pixels.

"And just as its strengths come almost entirely from its place in a system of other information sources, its privacy threats would come almost entirely from the abuse of that system," Loyd said. "Answering those threats (whether in the public or private sectors, US or foreign, targeted or not) has less to do with satellites than with governance."

Originally published July 26.

Update, July 29: Adds response from Planet Labs and Patrick Martinez.

Update Aug. 1: Adds response from Mapbox's Charlie Loyd.