we live in a rural high desert area of Arizona where the night sky is clear and every star can be seen with brightness. On this particular night, I happened to be looking up and saw an object streaking across the sky at a height that satellites are normally seen. It was not a satellite because it was traveling at a rate of speed that I estimate being over 2000 mph, using a commercial airliner as a gauge with normal speed being around 600 mph. It was going at least four times faster than a plane, at that speed. It was traveling due north, like a shooting star but not burning out when without slowing down, it made an abrupt 90 degree turn and headed due east. To my knowledge, we have nothing created or invented that could travel at the speed of this object, let alone maneuver a 90 degree turn without a wide sweeping curve. It continued the easterly path until out of site. No further information. I have seen UFO's including saucer type on at least three occasions during my life, but nothing like this object which obviously was being guided or flown with purpose and direction.