As I was walking north on a neighborhood road at about 1:40in the afternoon on my way to my office on Cruz Alta Road, Icaught a shiny point of light in my periphery out to thewest high over the mesa at approximately 45 degrees. Thesharpness of the reflected light appeared and disappeared infairly regular intervals, indicating that the object waseither tilting or rotating. It left no vapor trail, as iscommon with all planes that pass through the area.It's angle in the sky appeared to increase at the same timethat it's definition softened, until I couldn't see itanymore. It left the impression that it was moving higherand farther out west.Then, further along in my walk, I saw what appeared to be ajet in the same area that I saw the object. It was quitefar west over the mesa, and left a short dark vapor trail. My first interpretation was that it was this I had seen, andnot being able to see both objects at the same time (theother had faded), I was about to dismiss it.Then, further yet on my walk, the reflective object cameback into view, and I could clearly see it was differentfrom the object leaving the vapor trail. It was moving inan easterly direction on a course to cross my pathperpendicularly, traveling very steady in speed and altitudewith no sudden jerky movements. All the time, it pulsatedregularly with light reflected from the sun, atapproximately once per second. Eventually, it did comeright over my path. People driving by could have easilyverified it, but no one seemed curious as to what I waslooking at and I was too wrapped in it to stop anyone.When it was near overhead, I tried to see what it was. Since it appeared to be moving in the same direction of thewind, I couldn't rule out a piece of trash that had beenpicked up. But if it was, it was the only such piece oftrash in the entire clear blue cloudless sky, and ittraveled in a very smooth controlled manner, except for the"wobbling". My best interpretation was that is was 50%reflective and rotating, so that with each revolution itwould once again reflect the light of the sun. It may havebeen disc shaped, but the strong contrast between thereflective surface and the non-reflective "black" surfaceserved to disrupt a sense of shape. The wind was notblowing steadily at ground level, yet the object moved alongquite smoothly and slowly. Whatever it was doing (wobblingor rotating), it always appeared to be maintaining the same"top to bottom" orentation. In other words, at no point didit look like it was tumbling end over end, which is what Iwould have expected to see at times if it were merely apiece of trash at the mercy of the wind.It continued right along, traveling east and toward theSangre De Christo's and "flashing" in the sun, and thenbegan rising in altitude slowly as it made it's way over therange and out of sight. I must have watched it for a good5 minutes or more from the time it had reappeared, and Ihave no definitive conclusions as to what it was.