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OT - any ideas why the US military shut down access to the meteor satellites?

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  • OT - any ideas why the US military shut down access to the meteor satellites?

    the space debris info seems harmless enough.

    http://news.yahoo.com/s/space/200906...xpdGFyeWh1c2g-

    so it leaves me wondering, has the military put some debris up there that it doesn't want anyone knowing about? are they ABOUT to put some debris up there they don't want anyone knowing about? or are some space rocks heading our way that are about to make the dinosaur extinction look like a fire cracker?

    andy b.
    The danger is not that computers will come to think like men - but that men will come to think like computers. - some guy on another forum not dedicated to machining

  • #2
    Those satellites are for spotting rocks and stuff that has already hit us as well as nuclear tests in the atmosphere. With North Korea and Iran coming close to being able to make a real nuclear weapon the are probably concerned about giving out information that would allow calibration of the detection thresholds of the sensors.

    Detecting incoming threats such as asteroids before they hit is the job of the Lincoln Near-Earth Asteroid Research (LINEAR) Program. These are adaptive optics telescopes that are good enough to easily spot missing tiles and insulation on the shuttle in orbit.
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    • #3
      More likely just another Obama administration budget cut.

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      • #4
        Probably... they don't want people to know the full capabilities of their satellites.

        Tom M.

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        • #5
          If you think it's something funky, keep an eye on the induced error they can encode into the GPS signals to return. I'd guess that's next on the domestic pre-war situation checklist.

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          • #6
            That is called "Selective Availability" and I have a feeling they are already turning it back on. I went to town a couple of weeks back and wore my Garmin wrist GPS. When I got home I hooked it to the 'puter and forgot about it for a week while it just keep recording it's location. This is what it recorded and the errors are much larger than usual. It was sitting in my living room next to the main window where it has a good look at the sky. The error looks to be on average 100 to 200 feet which is typical of what to expect when selective availability is turned on. The use of Selective Availability is strictly up to the president and all it takes to turn it on or off is his orders.

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            • #7
              This is the same thing but recorded one year ago. I didn't leave it on very long but the scatter is typical of full accuracy with Selective Availability turned off.

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              • #8
                So you're saying you don't live on an active fault line?

                Doesn't surprise me at all that it's back on. I was more surprised they turned it off considering it would be relatively low level skill (for an electronics guy) to adapt a gps to a radio controlled aircraft and all of a sudden you have a drone with autopilot for a few hundred bucks.

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                • #9
                  Originally posted by dp
                  More likely just another Obama administration budget cut.

                  If Obama cut a budget, that's big news,

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                  • #10
                    Evan, your printout may have looked much better had you left the watch under a clear sky instead of near a window. You know, I'm sure, that the gps works better with more spread on the birds, that's why most if not all gps units show you a menu of where all the birds are on the horizon.

                    Neat printout at anyrate. Looks like the one I got from my gps while at anchor on a 50 foot rope in a small lake. That one was due to wind and currents and not satelite availability.
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                    Thank you to our families of soldiers, many of whom have given so much more then the rest of us for the Freedom we enjoy.

                    It is true, there is nothing free about freedom, don't be so quick to give it away.

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                    • #11
                      The Garmin Forerunner 205 is supposed to work inside as well as out. Sitting by the window it has a view of about half the sky so I wouldn't expect that spread, especially since a year ago it never looked like that.

                      Selective Availability can be turned on and off like a light switch and the amount of error on the civilian channels can be set to whatever they want. It is completely flexible and they can tune it for time of day to suit when the satellites pass over different parts of the planet as well as the type of error that is introduced. Errors can be random or they can be a Drunkard's Walk error which won't screw up survey instruments that take a long term set of readings and average it.
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                      • #12
                        Well, lets see:

                        Satellite detects N bomb tests.

                        Obama is making nice to Iran. It's called trust our enemies until they stab us in the back.

                        Obama probably wants to make nice to North Korea also. Why should they not be given an equal opportunity for back stabbing?

                        If satellite detects North Korean test and public gets data from it,

                        Obama can not deny that North Korea made the test.

                        Or Obama can not put out false information about the test if word gets out anyway (other resources or even North Korea announcement).

                        So Obama can not make nice with them in spite of the test.

                        So, Obama orders satellite data restricted.

                        Why should he allow facts to stand in the way of diplomatic stupidity?

                        Makes perfect sense.
                        Paul A.
                        SE Texas

                        Make it fit.
                        You can't win and there is a penalty for trying!

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                        • #13
                          Of course it makes sense, you want desperately for it to. Then again, if (insert name of currently hated administration / party here) was to have opened whatever resource to public use the response would be "look what they're giving away! We're doomed now!". The satellites in question detect atmospheric tests, they don't tell you diddly about underground tests, and the whacko in NK knows that. On the other hand, you can get info about missile launches from them, and the extent of that capability is something that you (they) may want to keep close. As for selective availability, it was shut off years ago, and the new block of satellites going into service don't even include the capability. It was found to be more trouble than it was worth, and with the FAA including GPS as an element of the new navigation package the chance of it returning is slim to none.

                          Joe

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                          • #14
                            The FAA navigation system includes and requires ground based GPS transmitters to achieve the necessary accuracy for zero-zero landings. A GPS transmitter doesn't have to be on a satellite, it can be anywhere you like and putting it on the ground makes it much more accurate since it isn't subject to all the errors of movement the space based clocks are subject to. That is called "Differential GPS" and the US is covered with DGPS transmitters. If SA is turned on and you are in the US you probably won't see a difference. Selective availability has no affect on the ground stations and so can still be implemented as required. If you really think it isn't in the new satellites then the question I have for you is "Why not?" It costs exactly nothing to implement, it's all in software. The software is not only all they need but it can be updated any time they wish.

                            Selective availability was first shut off during Desert Storm because the military didn't have enough mil spec GPS units to equip all troops that needed them. They quickly solved that problem by cleaning out Radio Shack and turning off SA. Carter later decided to keep it turned off because the benefits were obvious for commercial users. The other reason for turning it off was a simple matter of national pride. The Russian Glonass system is just as good and also reaches to medium orbit. The Eu Galileo system is also available and the Chinese are putting up their own system. None of the systems are compatible so the US system has the most hardware available.
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                            • #15
                              Desert Storm followed by Carter. Is my recollection of history that far out of whack???

                              Phil

                              [QUOTE=Evan]
                              Selective availability was first shut off during Desert Storm because the military didn't have enough mil spec GPS units to equip all troops that needed them. They quickly solved that problem by cleaning out Radio Shack and turning off SA. Carter later decided to keep it turned off because the benefits were obvious for commercial users. QUOTE]

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