REPORT SA.2193-2010 Compatibility between the space research service (Earth-to-space) and the systems in the fixed@ mobile and inter-satellite service in the band 22.55-23.15 GHz
ITU-R - International Telecommunication Union/ITU Radiocommunication Sector
Scope
"Introduction It is envisioned that three types of space mission would be supported by SRS earth station transmissions in the 22.55-23.15 GHz band: 1. low-Earth orbiting scientific satellites; 2. manned and unmanned lunar exploration missions; and 3. scientific missions using satellites located in the vicinity of the Sun-Earth L1 and L2 Lagrangian points. Data transmissions in the space-to-Earth direction for these types of missions are either currently operational or are planned to be operational in the 25.25-27.5 GHz band ?C a band allocated for both space-to-Earth and space-to-space transmissions to data relay satellites. Data relay satellites@ which are operated by several administrations (Recommendations ITU-R SA.1018 and ITU-R SA.1414)@ use the 22.55-23.55 GHz band for forward inter-orbit links and the 25.25-27.5 GHz band for return inter-orbit links to near-Earth orbiting user satellites. WRC-12 Agenda item 1.11 is ""to consider a primary allocation to the space research service (Earthto- space) within the band 22.55-23.15 GHz@ taking into account the results of ITU-R studies@ in accordance with Resolution 753 (WRC-07)"". The Earth-to-space allocation will complement the existing space-to-space (25.25-27.5 GHz) and space-to-Earth (25.5-27.0 GHz) allocations and add the capability to support near-Earth missions using similar@ if not identical technology@ on board the user satellite. The 22.55-23.15 GHz band will be used for both command and control of the user satellite@ and to support different applications within an exploration venture such as low-Earth orbit check-out@ manned or un-manned spacecraft support during transfer phase@ crew lander@ surface operations@ mission adjustment plans based on science and telemetry data with precise and high resolution instructions and graphics@ habitat@ data and software uploading@ re-programming@ payload check-out and ranging signals. Manned missions will additionally require voice and video links for communication with the Earth. The number of SRS earth stations transmitting in the 22.55-23.15 GHz band will be small. Rather than building new SRS earth stations@ upgrading selected existing SRS earth stations will predominate. Selecting which SRS earth stations to upgrade will be based on a number of factors@ including the type of mission to be supported. The maximum number of SRS earth stations capable of supporting lunar and/or L2 missions is not expected to exceed ten to fifteen on a global basis over the next few decades. A similar number of SRS earth stations may support LEO missions@ also on a global basis. These earth stations are typically located in rural@ isolated areas at mid-latitudes. Analyses have been performed to determine the criteria for transmitting earth stations in the space research service (SRS) to share with stations in the inter-satellite@ fixed and mobile services in the 22.55-23.15 GHz band. Analysed is the compatibility of SRS earth stations supporting three typical types of space research missions in the Earth-to-space direction in the 23 GHz band. These uplinks are to an SRS satellite in low-Earth orbit; in an orbit around the Moon or on the surface of the Moon; and@ in a halo orbit around the L2 Lagrange point. These analyses are presented in the following sections: Section 2 describes the approach used to assess the compatibility between SRS earth stations and stations in the inter-satellite service (ISS). Section 2 presents the technical and operating characteristics of the SRS earth station. Section 3 presents the characteristics of typical ISS space stations. The ISS systems are data relay satellite (DRS) users (this system is also representative of GSO-to-non-GSO inter-satellite links (ISLs))@ GSO-to-GSO ISLs@ GSO-to-non-GSO ISLs@ non-GSO-to-GSO ISLs and non-GSO-to-non- GSO ISLs. Section 3 also contains subsections describing the orbital characteristics of the Moon and observations on the characteristics of interference events. Sections 3 and 4 presents the results of the studies of sharing between transmitting SRS earth stations and space stations in the inter-satellite service. The conclusions of these studies are presented in ??.4. Section 5 addresses sharing between SRS earth stations and the fixed service. The subsections of ?? describe the static and dynamic approaches used to assess sharing and summarizes the technical and operating characteristics of the fixed and mobile systems considered and the typical separation distances required to protect fixed wireless stations. Section 5.4 presents the conclusions on the compatibility between a transmitting SRS earth station and P-P fixed wireless systems operating in the 22.55-23.15 GHz band. Section 6 presents an analysis of the compatibility between transmitting fixed wireless systems and low-Earth orbiting SRS satellites. Section 7 addresses the technical principles to protect mobile systems from interference due to the emissions of an SRS earth station operating in the 22.55-23.15 GHz band. Section 8 provides a summary of the results of the analyses and the conclusions."