Annex I System Description 1. General The European Meteorological Satellite System will continue the preoperational METEOSAT programme of geostationary satellites. The nominal position of the satellite will be over the O° meridian. The system will comprise a space segment and a ground segment. The design of the spacecraft will be based on that of METEOSAT. The ground segment will also make use of the experience gained during the preoperational METEOSAT programme and will provide for the tracking and control of the spacecraft and for central processing of the data. 2. Functional Description 2.1. Space segment The satellite will be equipped with the following capabilities: — Imagery in three spectral regions, visible, infra-red atmospheric window, infra-red water vapour band. — Dissemination of images and other data on two channels each capable of transmitting digital or analogue data to users stations. — Collection of data transmitted from in situ measuring stations. — Distribution of meteorological data to earth stations. 2.2. Ground segment The ground segment will provide the following functions, most of which have to be performed in near real-time to meet meteorological requirement, — Control, monitoring and operational use of one active satellite. — Possibility of controlling a second satellite not in operation. — Reception and preprocessing of image data. Preprocessing is the process of determining and adjusting for radiometric and geometric variations in the raw data. It will comprise as a minimum, mutual registration of the different channels, calibration of the infra-red atmospheric window channel, image localization. — Dissemination of preprocessed images to primary (PDUS) and secondary (SDUS) user stations. — Dissemination through the satellite of miscellaneous data including administrative messages and charts supplied from meteorological services. — Dissemination of images from other meteorological satellites. — Acquisition and limited processing of messages from in situ measuring stations (Data Collection Platforms [DCP]) and their dissemination. Dissemination of these messages will include both input to the meteorological Global Telecommunication System and transmission through the satellite to users stations. (These transmissions will be in addition to the other transmissions listed in this section). — Extraction of quantitative meteorological data, including wind vectors; other data needed for operational meteorology, such as sea surface temperature, upper tropospheric humidity, cloud amount and height; and a data set suitable for climatological purposes. — Archiving in digital form of all available images for a sliding period of at least five months and of all the produced elaborated meteorological information permanently. — Archiving on photographic film of at least 2 full disc images each day. — Retrieval of archived information. — Production and distribution of documentation including for instance an image catalogue and a system users' guide. — Quality control of products and transmissions. 3. Technical performance 3.1. Space segment The detailed performance specification for the spacecraft will be decided by the Council but will not be inferior to the specification for the preoperational METEOSATs except that the facility for "interrogating" data collection platforms through a dedicated down-link will be omitted. The following improvements are foreseen: — Improved lifetime as regards electric power and propellant. — Improved reliability of radiometer and electronics. — Water vapour channel to be brought to the same standard of design and manufacture as the other two channels; noise (interference) to be reduced. — Simultaneous operation of the infra-red window channel, the water vapour channel and both visible channels. — "In flight" calibration of the water vapour channel. — Temperature control of calibrating black body. — Modification of transponder to allow for distribution of digital data to earth stations in addition to preoperational METEOSAT functions. 3.2. Ground segment The technical performance for the functions listed in 2.2. shall at least be that of the preoperational system. The system will, however, be updated with the aim of improving reliability and reducing operating costs. 4. Bridging activities The operation of the existing system, including METEOSAT F1 and F2 and the satellite P2 (if launched within the framework of the preoperational programme) will also be incorporated with the operational programme with effect from 24 November 1983. 5. Launch Schedule 5.1. The operational programme will cover the procurement of components and building of sub-units necessary for three new flight models (MO1, MO2, MO3) and one spare. Only one integration team will be used and the spacecraft will be integrated sequentially. MO1 will be launched when ready, in principle in the first half of 1987. MO2 will be launched about one and a half years later, in principle in the second half of 1988. MO3 will be launched in principle in the second half of 1990. This launch date could be moved as warranted by the status of the programme and the availability of launchers at decision time. Insurance of the launches of MO1 and MO2 will be arranged in order to allow for integration and launch of an additional flight unit if necessary. 5.2. The maximum amount referred to in Annex II assumes that all launches will share a dual launch on ARIANE. The Council may decide by unanimous vote to use single launches if the programme requires it. 6. Duration of the programme The use of the operational satellites resulting from the tentative schedule is expected to be 8.5 years starting with the launch of MO1 in 1986/1987. In addition there will be bridging activities using existing satellites and providing operation of those satellites (F1, F2, P2) as available during the period from 24 November 1983 until the launch of MO1 in 1986/1987. The expected overall duration of the programme is 12.5 years from beginning 1983 until mid 1995.