Non-blinking/non-changing orange light moving west to east.We were driving westbound on I-90 at about 11pm, when we saw an aircraft in sky. I'm sure it was probably just an ordinary airplane, but this one seemed odd, because there was no pulsation or variation of the light at all. No blinking, no change what-so-ever. It looked similar to the way a satellite looks(only considerably bigger and a different color), but appeared to all of us to be much lower in the sky than a satellite. It seemed to be at about the same altitude that a small aircraft would fly. I'd estimate maybe only 4 or 5 thousand feet. It was a very deep unchanging orange/reddish color. It was moving the opposite direction as we were (west to east), and was visible for about 5 minutes before it just kind of blinked out. It wasn't moving particularly fast. I'd say maybe in the 100-125mph range? Like I said, it was probably just a plane I suppose, but I live near MSP and watch planes come in and out all the time, and this was weird looking because it was just static/unchanging. It almost seemed kind of ominous. 'Maybe some sort of balloon or flare caught in a fast moving upper air flow? Who knows.