This Recommendation provides methodologies to enable the measurement of the power flux-density (pfd) level emitted from a non-GSO space station incident at the antenna aperture of an operational GSO earth station receiver sharing the same frequency bands. This level can then be compared with operational epfd↓？limits provided in RR Article 22 to determine whether the non-GSO space station is exceeding these limits. These limits should be met in order to comply with RR No. 22.5I and also to protect GSO FSS links from suffering loss of synchronization or degraded performance1 due to the passage of non-GSO satellites close to or within the main beam of the GSO earth station antenna.