ENVISAT-1 Mission & System Summary ENVISAT-1 ENVISAT-1 Mission & System Summary Issue 2 Table of contents Table Table of contents 1 Introduction 3 Mission 4 System 8 Satellite 16 Payload Instruments 26 Products & Simulations 62 FOS 66 PDS 68 Overall Development and Verification Programme 74 Industrial Organization 78 Introduction Introduction 3 The impacts of mankind’s activities on the Earth’s environment is one of the major challenges facing the The -1 mission constists of three main elements: human race at the start of the third millennium. • the Polar Platform (); • the -1 Payload; The ecological consequences of human activities is of • the -1 Ground Segment. major concern, affecting all parts of the globe. Within less than a century, induced climate changes The development was initiated in 1989 as may be bigger than what those faced by humanity over a multimission platform; the -1 payload the last 10000 years. The ‘greenhouse effect’, acid rain, complement was approved in 1992 with the final the hole in the ozone layer, the systematic destruction decision concerning the industrial consortium being of forests are all triggering passionate debates. taken in March 1994. The -1 Ground Concept was approved in September 1994. This new awareness of the environmental and climatic changes that may be affecting our entire planet has These decisions resulted in three parallel industrial considerably increased scientific and political awareness developments, together producing the overall -1 of the need to analyse and understand the complex system. interactions between the Earth’s atmosphere, oceans, polar and land surfaces. The development, integration and test of the various elements are proceeding leading to a launch of the The perspective being able to make global observations -1 satellite planned for the end of this decade. by satellite of the Earth has fostered the development of The satellite is designed for an in-orbit mission lifetime a number of space-based remote sensing techniques. of 5 years. With its two satellites, has played a key role in the development of these techniques for a wide range of This document provides a brief description of the scientific and application oriented observations. -1 mission objectives and the underlying system design concept including all its major constituents and In 1988, an overall ‘Strategy for Earth Observation’ its relation to the operation strategy. It also describes the was presented to the member states. This proposed status of the design and development of the system a series of complementary polar-orbiting and elements. geostationary satellites to study the Earth’s environment and resources, to continue and improve meteorological observations. Based on this scenario, two councils at ministerial level, held in Munich in November 1991 and Granada in November 1992, established a programme composed of two missions: the -1 mission and the -1 mission preparatory programme. While -1 is primarily an operational meteorological satellite, -1 is a satellite dedicated to the study of the Earth and its environment. With its launch planned for the end of the decade, -1 is a multidisciplinary mission having science and application objectives, continuing and extending the -1/2 mission objectives and contributing to a coherent European Earth Observation Programme. Mission 4 Mission To monitor and study our environment at global scale, These objectives will be achieved by developing: polar orbiting remote sensing satellites offer unique • a package of instruments aimed at meeting the need to features: observe the Earth and its atmosphere from space in a • complete Earth coverage; synergetic fashion, addressing such matters as global • high revisiting rate; warming, climate change, ozone depletion and ocean • continuity of measurements over the seasons and and ice monitoring; years; • a ground segment including a flight operations segment, • stability and highly repeatible measurements. dedicated to spacecraft and mission control and operations; a payload data segment, ensuring payload However, due to the limited lifetime (a few years) of operations planning, data acquisition and processing, each satellite, the continuity of the measurements, which data distribution and archiving, and user services; taking is of paramount importance to monitor the evolution of into account the existing ground infrastructure and our environment and potential climate change, can only those of participating states. be ensured by flying a succession of polar orbit satellite missions. The mission is intended to continue and improve upon measurements initiated by -1 and -2, and taking In this context, the main objective of the -1 into account the requirements related to the global study programme is to endow Europe with an enhanced and monitoring of the Earth and its environment as capability for the remote sensing of the Earth from expressed by international cooperative programmes such space, with the aim of further increasing the capacity of as the International Geosphere and Biosphere participating states to take part in the study and Programme and the World Climate Research monitoring of the Earth and its environment. Its Programme. The mission is an essential element in primary objectives are: ensuring the long term provision of continuous data • to provide for the continuity of the observations started sets, essential for addressing environmental and with the satellites, including those obtained using climatological issues. The mission will at the same time radar-based observations; further promote the gradual transfer of applications of • to provide for the enhancement of the -1 mission, remote sensing data from experimental to pre- notably its ocean and ice missions; operational and operational exploitation. • to extend the range of parameters observed to meet the need to increase knowledge of the factors determining the environment; • to make a significant contribution to environmental studies, notably in the areas of atmospheric chemistry and ocean studies (including marine biology); coupled with two linked secondary objectives: • to allow more effective monitoring and management of the Earth’s resources; • to better understand solid Earth processes. The -1 satellite comprises a set of developed instruments (’s) complemented by Announcement of Opportunity Instruments (’s) embarked on the Polar Platform: ESA Developed Instruments (EDI’s) MERIS (Medium Resolution Imaging Spectrometer) Mission MIPAS 5 (Michelson Interferometric Passive Atmospheric Sounder) ASAR (Advanced Synthetic Aperture Radar) GOMOS Part of the payload is focussed on ensuring the (Global Ozone Monitoring by Occultation of Stars) continuity of the -1/2 missions: , , , RA2 -2 with its supporting instrumentation (, (Radar Altimeter 2) and ). MWR (Microwave Radiometer) The observation of the ocean and coastal waters is the LRR primary objective of the instrument. (Laser Retro Reflector) The ability to observe the atmosphere, following on Announcement of Opportunity Instruments from the instrument on -2, is significantly (AOI’s) enhanced by 3 instruments on -1 which offer SCIAMACHY complementary measurement capabilitites: (Scanning Imaging Absorption Spectrometer for Atmospheric • observation of a large quantity of atmospheric species Chartography) by analysis of the absorption lines through the AATSR atmosphere; (Advanced Along Track Scanning Radiometer) • characterisation of the atmospheric layers as well as total DORIS column content by complementary limb and nadir (Doppler Orbitography and Radiopositioning Integrated by Satellite) observations. These instruments operate over a wide range of the electromagnetic spectrum, from centimetre waves to ultraviolet. Instruments ASAR GOMOS RA-2 MERIS MIPAS MWR LR SCIAMACHY DORIS AATSR Disciplines (Parameters) The -1 mission includes both global and regional mission objectives with the corresponding need Atmosphere to provide data to both scientific and application users. Clouds Humidity Radiative Fluxes Temperature Trace Gases Aerosols Land Surface Temperature Vegetation Characteristics Surface Elevation Ocean Ocean Colour Sea Surface Temperature Surface Topography Turbidity Wave Characteristics Marine Geoid Ice Extent Snow Cover Topography Temperature Instrument Contributions to -1 Mission Objectives Global Requirements Regional Requirements Continuous and coherent global data sets are needed Regional data sets are needed by the scientific and by the scientific and application community to better application user community for understand climatic processes and to improve climate a variety of objectives such as: models. • sea ice tactical and strategic off-shore applications Some of the global objectives require products available • snow and ice detection and mapping in an off-line mode (days to weeks from sensing). • coastal processes and pollution monitoring Mission Specific examples include quantitative monitoring of: • ship traffic monitoring 6 • radiative processes • agriculture and forestry monitoring • ocean-atmosphere heat and momentum exchange (including tropical zones) • interaction between atmosphere and land or ice surfaces • soil moisture monitoring and large scale vegetation • composition of the atmosphere and associated chemical processes processes • geological features and mineral resources • ocean dynamics and variability • applications linked to interferometry • ice sheet characteristics and sea-ice distribution and ( generation, hazard monitoring, etc.) dynamics •