orange/amberish orb sighted on the ground in the early morning hours

I was driving to work at 0420 and I was about a mile from home headed toward the south to St. Paul International Airport. I noticed this bright orange/amberish orb to my right, the west, in a field on the ground. I watched it as I drove by it for about a minute or two. It was about 15 feet in diameter. There were no apparent doors or windows seen. No blinking lights of any kind. I didn't hear any sound, but I believe I had my window rolled up. I didn't see any movement around it as I was watching for people or something to clarify what I was seeing. There was no one else on the road; it was very dark. For the next several mornings I watched the same area, but it did not reappear. If it was an aircraft I would have known as I grew up by Camp Ripley and used to watch the military jets and helicopters fly over day and night. I am also a private pilot and an A & P mechanic so I am quite familiar with the majority of  aircraft and their lighting.