Factual error: This line of thinking is repeated twice, once by the NASA scientist and once by the Tommy Lee Jones character: "To get to the moon, you only have to go halfway - gravity will take you the rest of the way". Actually, since Earth's gravity is 6 times greater than the moon's, you would have to go 6/7ths of the way, otherwise you return to Earth.
Factual error: The Russian says that the missiles in IKON are locked onto American cities. The implication is that those cities will be destroyed if Eastwood screws up. Actually, since the orbit has decayed from geosynchronous (an altitude of roughly 22,000 miles) to low Earth orbit at 1000 miles, I don't think the missile guidance systems would get a chance to work. If the missiles were launched, they would simply shoot down toward the Earth and blow up wherever they happened to be. So, prayers to anyone unlucky enough to be directly below those missles.