Spy satellite resolution....teency bit scary...

**danholo** · 05-09-12 at 05:21 AM

I guess none of you ever used a telescope. What is the resolution of an eye...?

**Mbbest** · 05-09-12 at 06:12 AM

Quote: Originally Posted by voodu

10cm is not enough for facial recognition.

The mirror geometry is one of the physics limitations I am talking about. You can calculate theoretical resolving power quite easily if you know mirror geometry and distance from target.

Distance is governed by orbit height. Early spy satellites were essentially disposable because they had phsyical film cannisters...they could be maneuvered into very low orbits for critical missions to improve resolution. Modern satellites cost billions and are expected to last much longer and hence operate at a higher orbit and don't do these maneuveres (orbital decay is much faster at LEOs)

Mirror diameter is limited by payload vehicle. You can't launch a 200m mirror into space, its not possible. And also surface imperfections are another problem in making a large mirror.

Also you have atmospheric distortion. There are techniques for compensating this but you still can't achieve the resolutions that hollywood would have you believe.

At the end of the day there is a reason why drones and spy planes exist. Satellites are good but the Hollywood thing where they are following vehicles in real time and looking in the window at the driver etc....these are fiction

Yep, I agree, but in theory they can have 10cm resolution. And by my estimate atmospheric distortion is biggest problem. Thats why we have drones...what purpose of super-satellite if there is small amount of clouds..I have small telescope and even with "perfect" clear sky you will always have atmospheric distortion like evaporation etc...

**ItalicPixels** · 05-09-12 at 06:25 AM

Power of satellites, even old ones is amazing.

dannie9 · 05-09-12 at 10:05 AM

not too surprising

RaptorHunter · 05-09-12 at 11:52 AM

You can use a satellite to read whats is written on the verse back of the page of a book...

TKMaster · 05-09-12 at 11:59 AM

Uhh guys correct me if i'm wrong but aren't there telescopes that can even show us the ground of other planets? so with that in mind i imagine that if the government wants to they can get some ridiculously super zoomed photos of earth since the satellites are pretty damn close (well way closer than any planet anyway).

RaptorHunter · 05-09-12 at 12:48 PM

Quote: Originally Posted by TKMaster

Uhh guys correct me if i'm wrong but aren't there telescopes that can even show us the ground of other planets? so with that in mind i imagine that if the government wants to they can get some ridiculously super zoomed photos of earth since the satellites are pretty damn close (well way closer than any planet anyway).

First I don't know of any planet outside the solar system that had its surface photograph, finding large Jupiter sized planets its possible by measuring it's gravitational effects on it's parent star, smaller planets are being discovered by Kepler, but still no surface photography only analyses of their spectral lines.

And one big no no for high detail photography from space, it's the earth atmosphere, winds, temperature variations and other factors distort the image.

rtjnyoface · 05-09-12 at 01:51 PM

I've read all the comments and I'm unsure if I can come to any conclusion other than the satellites are strong enough to have clear images up to....well quite close (can I be more ambiguous? lol).

All I can say is....if the images from the late 60's were that clear, they must be more clear given the 40 years since. Scratches on a dime? I don't know, but they have to be quite clear. Facial recognition clear? Uh.....probably if not then close. Sorry but given the pictures referenced in the first post I can't really come to any other conclusion.

voodu · 05-09-12 at 02:37 PM

Quote: Originally Posted by rtjnyoface

All I can say is....if the images from the late 60's were that clear, they must be more clear given the 40 years since. Scratches on a dime? I don't know, but they have to be quite clear. Facial recognition clear? Uh.....probably if not then close. Sorry but given the pictures referenced in the first post I can't really come to any other conclusion.

Technology has advanced since the 1960s, but the laws of physics have not changed.

To see a dime in a mans hand from 300km away, you would need a telescope with ~100m diameter mirror. Try making that and getting it into space. Hubble is 2.4m. The largest ground-based mirrors are usually <10m because it is very difficult to make such a thing with no surface imperfections.

Real spy satellites can resolve objects about 20-50cm. That means they can see the shape of a vehicle and possibly a person (eg troop movements) but certainly not facial detail or licence plate numbers.

They are not much better than commerical imaging satellites because they all come up against the same physics limitations. That's why US government uses a lot of commerical satellites anyway, ie they are close to their own and 'good enough' for what they need.

**Mbbest** · 05-09-12 at 11:31 PM

I think we need some image for sample :D yay!

Here it one photo from Google satellite, it is commercial use and anyone practically can order one, just pay and point to the place lol :D

I would say that army can do at least 50% better views if not more combining several satelites at once, with 3D space. Oh..and click for full resolution :P

Code: Select All

http://odstatic.com/ojobuscador.com/inauguracion-obama.jpg

That ants down there are peoples on Obama inauguracion

I couldn't put picture here so its coded..

**Noledox** · 05-12-12 at 11:12 PM

Quote: Originally Posted by nofile404

"Technology has advanced since the 1960s, but the laws of physics have not changed."

Exáctamente, Raptor, "atmospheric effects, i.e.; winds, temperature variations and other factors distort an image."

During my time with the Agency, I served as what it called a "police rifleman"; most other agencies designate the position as "sniper". One of the biggest problems in accuracy is called "boil": heat waves rising from warm surfaces in combination with wind will, literally, change the apparent location of an object as well as it's appearance ... and this at distances of less than 1000 yds. [+/-300 meters] All the technical improvement in the world [or out of it] doesn't change the physics.

On the other hand, the heat waves emanate from the ground, and the satellite is not taking a picture along ~1000 yards at near ground level. Supposedly, large ground-based telescopes have greatly diminished the effect of higher-altitude turbulence with adaptive optics, so it's conceivable that a space-based telescope may be able to do the same. I doubt they'll be reading the face of a dime, but the known limits have probably been pushed.

05-09-12 at 11:31 PM	#24
Mbbest No kitty! bad kitty!!! Join Date: Aug 2008 Location: Southpark Posts: 1,660	I think we need some image for sample :D yay! Here it one photo from Google satellite, it is commercial use and anyone practically can order one, just pay and point to the place lol :D I would say that army can do at least 50% better views if not more combining several satelites at once, with 3D space. Oh..and click for full resolution :P Code: Select All http://odstatic.com/ojobuscador.com/inauguracion-obama.jpg That ants down there are peoples on Obama inauguracion I couldn't put picture here so its coded.. Last edited by Mbbest; 05-09-12 at 11:33 PM.

05-09-12 at 05:21 AM	#15
danholo Newcomer Join Date: Mar 2010 Posts: 30	I guess none of you ever used a telescope. What is the resolution of an eye...?

05-09-12 at 06:12 AM	#16
Mbbest No kitty! bad kitty!!! Join Date: Aug 2008 Location: Southpark Posts: 1,660	Quote: Originally Posted by voodu 10cm is not enough for facial recognition. The mirror geometry is one of the physics limitations I am talking about. You can calculate theoretical resolving power quite easily if you know mirror geometry and distance from target. Distance is governed by orbit height. Early spy satellites were essentially disposable because they had phsyical film cannisters...they could be maneuvered into very low orbits for critical missions to improve resolution. Modern satellites cost billions and are expected to last much longer and hence operate at a higher orbit and don't do these maneuveres (orbital decay is much faster at LEOs) Mirror diameter is limited by payload vehicle. You can't launch a 200m mirror into space, its not possible. And also surface imperfections are another problem in making a large mirror. Also you have atmospheric distortion. There are techniques for compensating this but you still can't achieve the resolutions that hollywood would have you believe. At the end of the day there is a reason why drones and spy planes exist. Satellites are good but the Hollywood thing where they are following vehicles in real time and looking in the window at the driver etc....these are fiction Yep, I agree, but in theory they can have 10cm resolution. And by my estimate atmospheric distortion is biggest problem. Thats why we have drones...what purpose of super-satellite if there is small amount of clouds..I have small telescope and even with "perfect" clear sky you will always have atmospheric distortion like evaporation etc...

05-09-12 at 06:25 AM	#17
ItalicPixels Elite Join Date: Jun 2011 Location: Italic Ocean Posts: 2,191	Power of satellites, even old ones is amazing.

05-09-12 at 10:05 AM	#18
dannie9 Expert Join Date: Dec 2011 Posts: 641	not too surprising

05-09-12 at 11:52 AM	#19
RaptorHunter Apprentice Join Date: Nov 2011 Location: 3rd Rock Body From Sol System Posts: 412	You can use a satellite to read whats is written on the verse back of the page of a book...

05-09-12 at 11:59 AM	#20
TKMaster Newcomer Join Date: Dec 2011 Posts: 13	Uhh guys correct me if i'm wrong but aren't there telescopes that can even show us the ground of other planets? so with that in mind i imagine that if the government wants to they can get some ridiculously super zoomed photos of earth since the satellites are pretty damn close (well way closer than any planet anyway).

05-09-12 at 12:48 PM	#21
RaptorHunter Apprentice Join Date: Nov 2011 Location: 3rd Rock Body From Sol System Posts: 412	Quote: Originally Posted by TKMaster Uhh guys correct me if i'm wrong but aren't there telescopes that can even show us the ground of other planets? so with that in mind i imagine that if the government wants to they can get some ridiculously super zoomed photos of earth since the satellites are pretty damn close (well way closer than any planet anyway). First I don't know of any planet outside the solar system that had its surface photograph, finding large Jupiter sized planets its possible by measuring it's gravitational effects on it's parent star, smaller planets are being discovered by Kepler, but still no surface photography only analyses of their spectral lines. And one big no no for high detail photography from space, it's the earth atmosphere, winds, temperature variations and other factors distort the image.

05-09-12 at 01:51 PM	#22
rtjnyoface Apprentice Join Date: Mar 2010 Location: Lost and Found Posts: 493	I've read all the comments and I'm unsure if I can come to any conclusion other than the satellites are strong enough to have clear images up to....well quite close (can I be more ambiguous? lol). All I can say is....if the images from the late 60's were that clear, they must be more clear given the 40 years since. Scratches on a dime? I don't know, but they have to be quite clear. Facial recognition clear? Uh.....probably if not then close. Sorry but given the pictures referenced in the first post I can't really come to any other conclusion.

05-09-12 at 02:37 PM	#23
voodu Apprentice Join Date: Jul 2010 Posts: 317	Quote: Originally Posted by rtjnyoface All I can say is....if the images from the late 60's were that clear, they must be more clear given the 40 years since. Scratches on a dime? I don't know, but they have to be quite clear. Facial recognition clear? Uh.....probably if not then close. Sorry but given the pictures referenced in the first post I can't really come to any other conclusion. Technology has advanced since the 1960s, but the laws of physics have not changed. To see a dime in a mans hand from 300km away, you would need a telescope with ~100m diameter mirror. Try making that and getting it into space. Hubble is 2.4m. The largest ground-based mirrors are usually <10m because it is very difficult to make such a thing with no surface imperfections. Real spy satellites can resolve objects about 20-50cm. That means they can see the shape of a vehicle and possibly a person (eg troop movements) but certainly not facial detail or licence plate numbers. They are not much better than commerical imaging satellites because they all come up against the same physics limitations. That's why US government uses a lot of commerical satellites anyway, ie they are close to their own and 'good enough' for what they need.

05-12-12 at 11:12 PM	#25
Noledox Bad command or file name Join Date: Jul 2010 Location: Terra Incognita Posts: 2,709	Quote: Originally Posted by nofile404 "Technology has advanced since the 1960s, but the laws of physics have not changed." Exáctamente, Raptor, "atmospheric effects, i.e.; winds, temperature variations and other factors distort an image." During my time with the Agency, I served as what it called a "police rifleman"; most other agencies designate the position as "sniper". One of the biggest problems in accuracy is called "boil": heat waves rising from warm surfaces in combination with wind will, literally, change the apparent location of an object as well as it's appearance ... and this at distances of less than 1000 yds. [+/-300 meters] All the technical improvement in the world [or out of it] doesn't change the physics. On the other hand, the heat waves emanate from the ground, and the satellite is not taking a picture along ~1000 yards at near ground level. Supposedly, large ground-based telescopes have greatly diminished the effect of higher-altitude turbulence with adaptive optics, so it's conceivable that a space-based telescope may be able to do the same. I doubt they'll be reading the face of a dime, but the known limits have probably been pushed.