"Atmospheric drag" is in fact an issue for *all* LEO satellites -- and every optical earth-imaging satellite spends some or all of its orbit "in the soup".
In fact, if you wanted to, you could place a satellite with the same lens configuration as the Hubble in the geosynchronous belt (about 22,000 miles out) to keep it stationary over a single spot the entire time and get pretty decent resolution.
Seems to me that the linear resolution from roughly 35,000 km with Hubble's 2.4m mirror is going to be about 25 feet -- that is, a single pixel will have a resolution (at nadir, if that means anything from geosynch) of only about 25 feet. Is that in the range you condsider "decent"?
The choice of orbital inclination and altitudes has much more to do with the desired resolution for a particular sensor, the revisit characteristics you want, and the shadows you want the sun angle to generate.
Large-ish LEO and MEO birds are sometimes deliberately DE-orbited at their end of life, allowing a predictable reentry/splashdown in an ocean, but most simply are allowed to run out of fuel during normal orbit maintenance burns and eventually re-enter and burn up in the atmosphere.
Satellites out in the extremely valuable real estate that makes up the geosynch ring are *supposed* to reserve enough fuel to re-orbit themselves at end of life, moving outwards from the 35,786 km geostationary orbit by an additional 300 km or so. (I suppose it would be fair to call this a "parking orbit" -- but it's really more of a "junkyard orbit".) From what I've read, though, only about a third of the geosynch operators actually do this, and as I recall there are more than 1,000 objects in the geostationary ring of which only about 350 are actually operational.
If the particular bird in question really is USA 193, the operators have had more than a year to try to recover the satellite; three more months is not likely to make any difference.
Even ignoring the incredibly tight mass budgets just about every satellite program struggles with and the huge amount of delta-V that would be required to boost a multi-ton satellite from LEO to an orbit that would (for all practical purposes) leave near-Earth space -- how would you propose to control these "emergency rockets" if the satellite in question has lost power?
Before you suggest a completely separate power system and receiver, let's figure out how we're going to orient the satellite so that the "emergency rockets" are actually pointed in the right direction. Are we adding separate reaction wheels or control-moment gyros as well?
...but as long as you've got fuel on board (and the fact that this thing doesn't anymore is notable) you can at least move its orbit around so you're not in the exact same space they'd be looking for you next time
The amount of fuel carried aboard a satellite in low-Earth orbit allows for maintenance of orbit altitude and little else. The delta-V (and therefore the amount of fuel) required to change orbital inclination is significant. The notion that ground operators "move a satellite around it its orbit" just doesn't work.
Do you understand anything about orbital mechanics?
Orbiting spacecraft cannot "loiter" except in a very few, very special kinds of orbits. The cannot meaningfully "reposition" with the specific impulse limitations of the engines and fuel available today.
Oh, the heck with it: for all intents and purposes they cannot meaningfully do ANY of the things your message suggests.
I can't think of any other reason the surgeon in the linked photo (who is described as being far away from his patients) in the additional details and pictures link is wearing scrubs and a hairnet.
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"Atmospheric drag" is in fact an issue for *all* LEO satellites -- and every optical earth-imaging satellite spends some or all of its orbit "in the soup".
In fact, if you wanted to, you could place a satellite with the same lens configuration as the Hubble in the geosynchronous belt (about 22,000 miles out) to keep it stationary over a single spot the entire time and get pretty decent resolution.
Seems to me that the linear resolution from roughly 35,000 km with Hubble's 2.4m mirror is going to be about 25 feet -- that is, a single pixel will have a resolution (at nadir, if that means anything from geosynch) of only about 25 feet. Is that in the range you condsider "decent"?
The choice of orbital inclination and altitudes has much more to do with the desired resolution for a particular sensor, the revisit characteristics you want, and the shadows you want the sun angle to generate.
Besides, Chthulu was quite pleased with the extra spicy snack.
Large-ish LEO and MEO birds are sometimes deliberately DE-orbited at their end of life, allowing a predictable reentry/splashdown in an ocean, but most simply are allowed to run out of fuel during normal orbit maintenance burns and eventually re-enter and burn up in the atmosphere.
Satellites out in the extremely valuable real estate that makes up the geosynch ring are *supposed* to reserve enough fuel to re-orbit themselves at end of life, moving outwards from the 35,786 km geostationary orbit by an additional 300 km or so. (I suppose it would be fair to call this a "parking orbit" -- but it's really more of a "junkyard orbit".) From what I've read, though, only about a third of the geosynch operators actually do this, and as I recall there are more than 1,000 objects in the geostationary ring of which only about 350 are actually operational.
If the particular bird in question really is USA 193, the operators have had more than a year to try to recover the satellite; three more months is not likely to make any difference.
Even ignoring the incredibly tight mass budgets just about every satellite program struggles with and the huge amount of delta-V that would be required to boost a multi-ton satellite from LEO to an orbit that would (for all practical purposes) leave near-Earth space -- how would you propose to control these "emergency rockets" if the satellite in question has lost power? Before you suggest a completely separate power system and receiver, let's figure out how we're going to orient the satellite so that the "emergency rockets" are actually pointed in the right direction. Are we adding separate reaction wheels or control-moment gyros as well?
...but as long as you've got fuel on board (and the fact that this thing doesn't anymore is notable) you can at least move its orbit around so you're not in the exact same space they'd be looking for you next time
The amount of fuel carried aboard a satellite in low-Earth orbit allows for maintenance of orbit altitude and little else. The delta-V (and therefore the amount of fuel) required to change orbital inclination is significant. The notion that ground operators "move a satellite around it its orbit" just doesn't work.
Unfortunately, on the 1,000,001th rehash, we began to see read errors. Who knew?
You're talking about bubbles formed from methane hydrates. There are huge deposits of such around the ocean seafloors, especially in the North Sea.
Do you understand anything about orbital mechanics? Orbiting spacecraft cannot "loiter" except in a very few, very special kinds of orbits. The cannot meaningfully "reposition" with the specific impulse limitations of the engines and fuel available today. Oh, the heck with it: for all intents and purposes they cannot meaningfully do ANY of the things your message suggests.
...and it revives right up over a hot griddle!
I can't think of any other reason the surgeon in the linked photo (who is described as being far away from his patients) in the additional details and pictures link is wearing scrubs and a hairnet.