RES157 – 253 – d) in the frequency band 6 700-7 025 MHz, the protection of feeder links for MSS systems operating in the space-to-Earth direction from unacceptable interference, pursuant to existing criteria, from non-GSO FSS system earth stations operating in the Earth-to-space direction; e) in the frequency band 4 500-4 800 MHz (space-to-Earth), the development of appropriate regulatory provisions for non-GSO FSS systems to protect terrestrial services; f) in the frequency bands 4 500-4 800 MHz (space-to-Earth) and 5 925-6 425 MHz (Earth-to-space), the development of regulatory provisions to clarify that Nos. 5.440A and 5.457C would apply in a manner to ensure that non-GSO FSS systems do not cause harmful interference to, or claim protection from, AMT for flight testing by aircraft stations, further resolves 1 that the results of studies referred to in the resolves above shall: – in no way change the protection criteria and protection levels defined in those criteria for the GSO FSS, the fixed service and the mobile service; – ensure protection of the existing non-GSO FSS systems with highly-elliptical orbits, 2 that new non-GSO systems that operate in FSS bands subject to the provisions of Appendix 30B shall ensure that the allotments appearing in the Plan and the assignments of the List of Appendix 30B will be fully protected, invites administrations to participate in the studies by submitting contributions to the ITU Radiocommunication Sector, instructs the Director of the Radiocommunication Bureau to include in his report, for consideration by WRC-19, the results of the ITU-R studies referred to in resolves to invite the ITU Radiocommunication Sector above.