REQUIREMENTS FOR A FUTURE LAND SURFACE PROCESSES MISSION 
M. RAST P. KEALY 
Earth Sciences Division. 
ESA-ESTEC, 
Noordwijk, The Netherlands. 
1. INTRODUCTION 
After the successful launch of ERS-1 and with ERS-2 being finalised for launch in 1994, the European Space 
Agency has set the scene for a meteorological-ocean-climate mission with particular emphasis on ocean and ice 
processes. Beyond ERS, ESA is trying to meet the requirements of the user/science community with regards to 
our environment and is presently preparing the mission of the environmental satellite ENVISAT-1. 
This platform is aimed mainly at the continuation and extension of the ERS missions and focuses on 
environmental studies, with some emphasis on oceanography and atmospheric chemistry. In parallel, a senes of 
missions called METOP are under study with EUMETSAT. These are intended to make a major contribution to 
operational meteorology. The proposed launch date for ENVISAT-1 is 1998 and for METOP the year 2000. 
In formulating European Earth observation missions beyond these, ESA is considering as one mission 
possibility, the establishment of a high resolution land surface processes mission. This is the subject of this 
paper. 
2. ESA’s EARTH OBSERVATION STRATEGY 
To obtain a better understanding of the Earth as a system, the physical, chemical and biological interactions 
between the atmosphere, oceans, land, and ice must all be taken into account Fundamental to this philosophy is 
the provision of data to identify processes and validate models. These data are also needed to monitor the state of 
the Earth system and to detect changes. In most instances long term continuity of data is essential for 
climatological and environmental studies. This leads to the requirement to sustain space-borne capabilities for 
periods of a decade or more by replacing space-borne systems at the end of their lives. These needs are addressed 
in the Earth observation programme proposed by ESA. 
The ESA Earth observation strategy has been established in collaboration with the user community and 
representatives of the member states. The basic objectives of the ESA programme are: 
1. Monitoring of the Earth’s environment at various scales, from local through to regional and global 
scale. 
2. Monitoring and management of Earth resources both renewable and non-renewable. 
3. Continuation of the services provided to the world-wide operational meteorological community. 
4. Contribution to the understanding of the structure and dynamics of the Earth's crust and interior. 
The following satellite missions have been or are being developed in support of the Earth observation strategy 
outlined above. 
1. ERS-1 
2. ERS-2 
3. ЮЕМ Programme : 
ENVISAT-1 
METOP 
4. Meteosat Second Generation (MSG) 
5. POEM-Next 
(Launched in 1991) 
(Launch in 1994) 
(Launch in 1998) 
(Launch in 2000) 
(Launch in 1999) 
(Launch in 2003)