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Implications of Commercial 1m Res Satellite
One-eyed Orbital Snake writes "Interesting essay in the NYT magazine (free login, yadda yadda) on commercial 1m resolution satellite photos, with the Sept. 24 launch of Space Images' Ikonos. Not much new, but well written and all in one place. References Clarke's 2061, Brin's Transparent Society, and ties it all up with a heartwarming 1st Amendment ribbon. Definitely worth a read."
High resolution sensors such as Landsat TM (25m) and SPOT PAN (10m) have repeat rates of the order of 28 days, as will the new generation of 1m satellites. Actually SPOT has a tilting sensor which gives it a revisit facility as well as the option of producing stereo pairs. This is also a feauture of the new satellites.The repeat period (a month) means that you cannot use these satellites for the kind of surveillance that a lot of people worry about. Combine this with the fact that 80% of the Earth's surface is cloud-covered at any time and you'll see what I mean. These sensors have no thermal infrared capabilities at this resolution so you can't use them for spotting tanks or anything like that. You CAN use it to spot semi-permanent structures such as missile launchers and dug-in tanks - but you've been able to do this with SPOT for a long time.
Another note on resolution - there is a theoretical limit on spatial resolution, determined by atmospheric scattering. It's about 15cm. So a spy sattelite, on a perfectcly clear day, could, just about, be used to tell what kind of car you are driving - certainly not to read the number plate (which is kind of hard from a nadir view anyway). Forget geostationary satellites - they sit at an altitude of 35800km over the equator which means you get oblique views of most stuff, and lousy resolution (15km). They're great for synoptic weather (and telecomms obviously) but that's about it.
The people who should be worrying about the new high-res satellites are the air-survey crews. This could well put them out of a job for medium-scale photogrammetric surveying.
Nick Yes
I am a PhD student in remote sensing...
-- "It's a sad day for American capitalism when a man can't fly a midget on a kite over Central Park" - Jim Moran
For 4 years I've been working on Remote sensing. I feel that there's a missconception about satellite imagery. 1m resolution is not so "Hi Res" imagery. Same imagery has been around for years in form of aerial photography, let's say, for more than 40 years. Yes, the times have changed, now images are processed and used with computers, you have powerfull geographic information systems, etc...but privacy is still the same... There's no way that 1m resolution can be used to see french girls topless in ibiza, or if you are wearing red shirts or even if you read marx or bradbury... 1m resolution can show if you built a new room in your house, or if that nice swiming pool you built in your house is big or small. Just like walking and watching from the street... In military applications, every government of the planet knows the satellite orbits, and no one will test that "hot new tank" while the satellite is above them. Russians knew that US planes and satellites were taking images during the cold war, and funny things happened, but I can't remember a serious discovery in the intelligence field, when everybody knew what was going around. Maybe in the first years it was secret, but quickly it became obvious that imagery was just a control tool, nor a real secret eye in the space. This reminds me "The Simpsons" when the goverment guys say they don't know where monty burns hides the 1 billion dollars note, but sattelites show that is not in the roof...that's the real thing... Real privacy violations are coming, but not 1m resolution images...maybe electromagnetic scaning of monitors activity, or laser microphones targeted to our windows, but...jejeje...not ikonos from the space... just my 2 cents...