A method for operating one or more satellites in a non-geosynchronous orbit NGSO satellite constellation, the method comprising: determining a coverage area on Earth for a first beam transmitted from a first satellite in the NGSO satellite constellation; projecting a cone onto a first region of the beam coverage area, the first region of the beam coverage area corresponding to an area on the Earth's surface for which a power flux density PFD is greater than a threshold PFD level; defining a second region of the beam coverage area as including portions of the beam coverage area lying outside the first region, the second region of the beam coverage area not interfering with geosynchronous orbit GSO satellite communications; determining a minimum arc angle for each of a plurality of points within the first region but not the second region of the beam coverage area, wherein the arc angle for each of the plurality of points is determined as the angle between a first line extending from the point to an example position along the GSO arc and a second line extending from the point to the NGSO satellite; for a selected one of the plurality of points within the first region, comparing the determined minimum arc angle for the selected point with a threshold angle, the threshold angle corresponding to a specified EPFD limit; and based on the determined minimum arc angle being less than the threshold angle: disabling the first beam and selecting another point of the plurality of points, or reducing a power level of the first beam, and/or modifying a shape or size of the first beam, or redirecting the first beam to another coverage area on Earth, the minimum arc angles associated with the other coverage area being greater than or equal to the threshold angle. determining a coverage area on Earth for a first beam transmitted from a first satellite in the NGSO satellite constellation; projecting a cone onto a first region of the beam coverage area, the first region of the beam coverage area corresponding to an area on the Earth's surface for which a power flux density PFD is greater than a threshold PFD level; defining a second region of the beam coverage area as including portions of the beam coverage area lying outside the first region, the second region of the beam coverage area not interfering with geosynchronous orbit GSO satellite communications; determining a minimum arc angle for each of a plurality of points within the first region but not the second region of the beam coverage area, wherein the arc angle for each of the plurality of points is determined as the angle between a first line extending from the point to an example position along the GSO arc and a second line extending from the point to the NGSO satellite; for a selected one of the plurality of points within the first region, comparing the determined minimum arc angle for the selected point with a threshold angle, the threshold angle corresponding to a specified EPFD limit; and based on the determined minimum arc angle being less than the threshold angle: disabling the first beam and selecting another point of the plurality of points, or reducing a power level of the first beam, and/or modifying a shape or size of the first beam, or disabling the first beam and selecting another point of the plurality of points, or reducing a power level of the first beam, and/or modifying a shape or size of the first beam, or redirecting the first beam to another coverage area on Earth, the minimum arc angles associated with the other coverage area being greater than or equal to the threshold angle.