RES739 – 385 – d) that Recommendation ITU-R S.1586 provides a methodology based on the epfd concept for calculation of interference resulting from unwanted emissions from non-GSO systems of the FSS into radio astronomy stations; e) that the methodology described in these Recommendations may also be used to study the case of non-GSO systems in the BSS; f) that Recommendation ITU-R RA.1631 provides antenna patterns to be used for compatibility analyses between non-GSO systems and RAS stations, based on the epfd concept; g) that Recommendation ITU-R RA.1513 provides acceptable levels of data loss to radio astronomy observations, stating in particular that the percentage of data loss caused by any system should be lower than 2%; h) that some of the results documented in Report ITU-R SM.2091 may be used as threshold levels to initiate the consultation procedure; i) that the results of successful consultation between concerned administrations would ensure that the interests of both the active and radio astronomy services are considered; j) that measures taken by active space services to protect radio astronomy stations from interference may result in increased costs and/or reduced capabilities for those services; k) that conversely, not taking such measures may result in additional operating costs and reduced operational effectiveness for the radio astronomy stations concerned; l) that the implementation of additional interference mitigation measures at the radio astronomy station may increase operating costs and reduce observational effectiveness; m) that conversely, not implementing such measures may impose upon the active space services an additional cost burden and reduction in service capability, recognizing a) that unwanted emissions produced by stations of the active space services may cause unacceptable interference to stations of the RAS; b) that, although some unwanted emissions from transmitters on space stations can be controlled through careful design methods and appropriate testing procedures, other unwanted emissions, such as narrow-band spurious emissions, generated by uncontrollable and/or unpredictable physical mechanisms, may only be detected after the spacecraft is launched; c) that there is an uncertainty in the pre-launch assessment of the levels of unwanted emissions; d) that it is necessary to ensure an equitable sharing of burden for achieving compatibility between the active space services and the RAS; e) that for those cases where difficulties are encountered in meeting the values in Annex 1, a consultation procedure could be used to resolve the difficulties,