A method for sensing and monitoring ICBM threats using a constellation of earth orbiting satellites. The method includes arranging a first and a second plurality of threat sensing satellites in earth orbit. The first plurality is selected to have a first prograde orbit plane with a first inclination angle between about 30.degree. to 70.degree. with respect to the earth's equator and an Argument of Perigee equal to about 270.degree.. The second plurality is selected to have a first retrograde orbit plane with a second inclination angle between about 110.degree. to 150.degree. with respect to the earth's equator and an Argument of Perigee equal to about 270.degree.. The second inclination angle is selected to be a symmetric conjugate of the first inclination angle. The first and second plurality of threat sensing satellites are distributed respectively within the first prograde and first retrograde orbits with a Walker distribution of T/P/1. Synchronization of a plurality of epochs of the first plurality of satellites with a plurality of epochs of the second plurality of satellites is performed to provide uniform inter-plane satellite spacing for improved monitoring of an ICBM threat.