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Bolivian Salt Flats Aid Spacecraft Calibration
PCOL writes "Salar de Uyuni is a vast plain of white salt in the mountains of Bolivia, with a total elevation range of less than 80 centimeters - the flattest place on earth. Beginning in 2002, geophysicist Adrian Borsa led a survey that resulted in precise GPS measurements of the salt flat. The flats will be used as a giant calibration device for satellite-based radar and laser altimeters on the CryoSat recovery mission so the spacecraft can more precisely monitor changes in the elevation and thickness of polar ice sheets and floating sea ice. 'Satellites can calibrate their altimeters by bouncing signals off the ocean surface .. because of atmospheric interference, tides and waves, there are uncertainties. Borsa says the salar, now so accurately mapped and with dry, clear skies, is about five times better than the ocean as a reference point.'"
Salar de Uyuni in Google Maps.
Karma: SELECT `karma` FROM `users` WHERE `userid`=138474;
Jesus effing Christ, everybody on this thread seems to be drunk.
Go to Wikipedia and figure it out yourself. Or better yet: go to bed and sleep. Look out of the window when you wake up tomorrow and try to find out why on earth you're not seeing the Chinamen in the far distance.
I'm an infovore...
The dried Bonneville Salt Flats (open to the public) and its attached military only area called the Dougway Proving Grounds are the flattest place on earth. They have been used by the military for the past 40+ years to calibrate space and weapons systems. Pretty much every land speed record has been made at the Bonneville Salt Flats, including breaking the sound barrier. The variation of altitude is so minimal that it is within the accuracy of the measurement equipment used to calibrate altitude variations, but it has been certified to be less than 1 foot of elevation for every 10 miles.
And every year it gets 'reset'... The springtime runoff from the surrounding mountains will cover the entire salt flats with a perfect 1/2" of water. It is SO COOOL to go out there when there is a *PERFECT* sheet of water covering the salt, it looks like the worlds largest piece of glass. You can actually *SEE* the curvature of the earth. I have a picture of a much younger me 'walking on water' because it is so smooth you cannot tell that the water is only 1/2" (1.5cm) deep.
Working out on the salt flats, doing surveys, the survey crew would drive out 1 mile and hold up a survey marker. At five miles out we could not see them any more, we asked them to raise it up over their heads and we saw the marker rise up over the horizon like it was the sun coming up.
Because it is the worlds largest and flattest spot on earth, my father, an engineer in flight optics systems, has built optical calibration targets used by the military to calibrate autopilot systems, weapons guidance systems, terrain following radar systems, satellite optics systems and all that jazz for the military... which is why I grew up in Utah, am intimately familiar with the flats, and know without a doubt that my dad has worked on black projects that I hope someday he'll be able to tell me about (including flights into and out of the Janet terminal).
Good security is based upon reality and common sense. Common sense is a function of having common knowledge.