the equation for any projectile is derived from newtons equations of motion:
where distance in the x direction is given by : x=Voxt and distance in the y direction is given by y=Voyt-(1/2)gt^2. Combineing these 2 equations gives us:y=xtan(theta) - g/(2Vo^2cos^2(theta)) which isn't parabolic. This equation is on the surface of the earth but to change it to work in anywhere you just do a small change to: y=xtan(theta)- GMe/[2(r^2)(Vo^2)(cos^2(theta))] where Me is the mass of the earth, G is the gravitational Constant, r is the distance from the center of the earth and theta is the angle at which the object is fired. This equation isn't parabolic either