No need for skillz, there are websites [flightradar24.com] that track stuff for you. (At least their coverage for non-US flights is ADS-B based, real time, and collected from private contributing scanners AFAIK, US flights go through FAA)
The brilliant fireball objects tend to have an orbital velocity, ie a significant horizontal component to their speed. I have not done the math, but if you get out of a balloon with 0 ground speed I can imagine it is less likely to hit fireball speeds before the atmosphere gets denser.
Moreover, ISS orbits with an apogee of 405 km above ground according to Wikipedia, while earths radius has a minimum of 6,357 km according to the same source. Not sure where the asteroid flew, but unless you mean that ISS orbits ~1 earth radius from the center of the earth, 1 earth radius does not equal the the orbit of the ISS.
And so did Germany at Kalkar http://en.wikipedia.org/wiki/SNR-300
No need to take it back. Medical radiation sources can be quite mobile and far from hospitals. http://environment.newscientist.com/article/dn3150 Get used to black cars trailing you if you happen to have a thyroid problem....