1. The problem statement, all variables and given/known data Find x, the distance from your location to space, as a function of the zenith angle. The height at 0 degrees, H, is ~100km. A picture helps more: http://img23.imageshack.us/img23/3630/picture1orr.jpg [Broken] 2. Relevant equations ??? 3. The attempt at a solution I've tried using the law of cosines to express the distance in terms of the Earth's radius and other known constants, but it seems like I'm over complicating the situation.