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#31
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Mike Adams wrote:
It's not and I don't see why it would be. It's the airplane owner that's missing. The airplane is just incidental. Ignore him. He is nothing more than a troll here. -- Peter |
#32
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![]() "Mxsmanic" wrote in message ... Gig 601XL Builder writes: The fuel value of moving a spy satellite just 1 degree to cover a specific area would pay for several 100 if not 1000s of CAP missions. I didn't say anything about moving a satellite, nor did I say anything about spy satellites. There may have been satellites already covering the area. Commercial satellites already have enough resolution to spot wreckage. So you think those pictures on Google Earth are real time. Satellites both commercial and government are in orbits that are designed to cover areas of interest. To task a satellite to cover a specific area that isn't under its flight path requires fuel to be used. The chances of any given place on any given week being covered is low. The exception to this is places where the government has special interest. I'm sure the Mid East is covered pretty well about now. |
#33
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Gig 601XL Builder writes:
So you think those pictures on Google Earth are real time. I didn't say anything about Google Earth, either. You can save a lot of time by concentrating on what I actually write, and skipping the speculation. -- Transpose mxsmanic and gmail to reach me by e-mail. |
#34
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On Fri, 6 Oct 2006 10:49:23 -0500, "Gig 601XL Builder" wrDOTgiaconaATcox.net
wrote: So you think those pictures on Google Earth are real time. Satellites both commercial and government are in orbits that are designed to cover areas of interest. To task a satellite to cover a specific area that isn't under its flight path requires fuel to be used. The chances of any given place on any given week being covered is low. The exception to this is places where the government has special interest. I'm sure the Mid East is covered pretty well about now. Not quite. There are few low-earth orbits where a given satellite can't see the entire Earth in a week. The major exceptions are those cases where the satellite inclination (orbit tilt with respect to the equatorial plane) low; in these cases, the satellite won't pass over higher latitudes at all. In any case, satellites that take imagery in natural light are generally in a sun-synchronous orbit. In this kind of orbit, the satellite's orbit plane stays in a fixed relationship with the sun. In this way, the satellite passes overhead at the same approximate ground time each day (and 12 hours later at night, too). The satellite's photos then always have the sun at the same local angle to optimize the images taken. The other factor is the altitude of the spacecraft. The lower the orbit, the closer the vehicle is to the target and the higher the photo resolution (too low, of course, and you quickly use up your propellant just keeping the thing in orbit). But by flying low, you lessen your Field Of Regard... the satellite can't see as much of the surface at given moment. A given target may fall right between two adjacent satellite passes, for instance. But unless the orbit meets some pretty specific criteria, it should pass over that target area within a couple of days. A satellite CAN change its orbit to catch that target, but the propellant cost is pretty fierce. It's traveling at ~18,000 MPH; changing the orbit may require the expenditure of enough propellant to change the velocity by ANOTHER 2,000 MPH. It's a lot cheaper just to put up a second satellite with complimentary coverage. As to why the news media don't have fresh S/C pictures every time something happens, the answer is "tasking." These satellites are pretty busy, and resources (including onboard storage capacity) have to be carefully planned. Ron Wanttaja |
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