You want a formula to calculate absolute optimal altitude? Number of seconds the mun take to rotate once divided by: number of hexes across the munar surface along the equator. that gives you the number of sec you want your orbit to take. (one orbit pr hex) call that number (T) Look up the muns GM (newtons gravitational constant x mass of the mun) and look up the radius of the mun, referred to in the formula as ® calculate: cuberoot((T²xGM)/4pi²) - r = your optimal scanning altitude. If that's inside the mun (ie "-something"), simply double (T) in your formula and you're all good. this will simply make you complete the surface scan in 2 munar "days". (if the number of hexes across the surface is an even number, instead of doubling it, multiply it by 1,5 or 3 to avoid scanning the same lines twice) Place your craft in a perfect circular polar orbit at your calculated altitude and you shouldn't miss a single hex. happy counting..