Visiting Badwater (lowest spot in USA) with family (two witnesses for this "event"). Can hear 1/2 dozen military aircraft sounds over the Telescope Peak toward China Lake. It captures my attention. I search and search toward the early afternoon soon to spot the aircraft. Scanning slightly toward the south-west-west, but VERY high in the sky, I see what appears to be a blue-white-ish star near the middle of the day 2PM+ or - a few minutes. I'm staring, thinking how unlikely it would be to see a star during this time of day - thought briefly, "Wow, a supernova???!!" I'd only heard about them, called my girlfriend over to see if she sees what I see. Her character is to be VERY skeptical about most things. We watched it for about 5 minutes. Then, it started moving toward the NE. Slowly, very slowly, but it was discernible. So, we tracked it - from the weather station positioned at Badwater in Death Valley. It still appeared blue-white, star-like - during DAYTIME, high above Death Valley at its very lowest part, but more toward the West side of the DV. Again, it was FAR higher than any known aircraft we're aware of (I was in USAF and have been in travel industry for 20 years) - we considered whether it was a satellite (and it certainly wasn't a geostationary), but they tend to move far faster based on our experiences - this was tracking slowly across the sky. Again, at what must be at the edge of our atmosphere...it was just too plain high for anything we've witnessed before. Then, it appeared to be "limping" along, stumbling...almost like a tumbling satellite. We hope someone there at MUFON will help us understand if there were satellites or test aircraft in the area - we were nearly smack dab half way between China Lake (the northern part of it) US Naval Weapons testing area, and Nellis + Area 51, so we were thinking...hmmmmmm.....We continued to track it for 15 minutes, moving slowly...tumbling. Then, it stopped. Did not appear to move position. For maybe another 5 minutes. It's brightness was mostly steady, except when it tended to appear to tumble. As it stopped, it dimmed a bit - this was now on the East side of Death Valley over Nellis AFB-Nevada test site, but it did NOT lose altitude. Again, maybe 5 minutes for the stop, then it began to move again. From there, it moved a bit further NE, losing its brightness until is vanished from our site - not like, "poof!", just that its brightness diminished into the blue of the sky. That's it - maybe 25 minutes of VERY intriguing sky watching. We continued to watch F16s/F15s tracing the Death Valley sky all afternoon. We've been unable to stop thinking about it since. We've NEVER reported a UFO before, and we've been combing the sightings Web sites to see if anyone else saw what we saw, but, we've not yet found any similar reports on/about this date/time. We'd love to hear back if there were any others who saw something similar.We've no photos - it was FAR too high in the sky and simply would not have shown up.