After a decade of ERS-2 Earth Observation, the Mission Continues.

The ERS system together with other European and international missions provides long-term uninterrupted observation of many key environmental variables, including:   ERS data products have created and are still the basis for a large number of scientific projects and operational services, with important contributions now for the new European initiative for Global Monitoring for Environment and Security (GMES). ERS - 2 Launch from Kourou, French Guiana 21 April 1995 Launcher Ariane 4   Launch mass   2516 kg Number of instruments 4/5 including SAR with GOME added to ERS-2   Orbit Sun synchronous, altitude 800 km   Inclination 98.5 degrees   Time for one orbit 100 minutes   Cycle 35 day repeat   "More than 3,000 scientists have published over 10,000 scientific papers based on ERS data"   Hector Mine earthquake   The ERS system, together with other European and international missions, ensures the long-term, uninterrupted observation of environmental parameters that is crucial to our understanding of the Earth system. The resultant databases match, by virtue of their continuity, the requirements for distinguishing trends that are influenced by human acitivity and those that relate to natural proceses. ERS-2 is in an excellent operational state, enabling further years of service. All instruments are working well. Platform fuel reserves are more than sufficient. A global network of ground stations continue to acquire SAR data. Failure of the on-board data recorders is being offset by the increasing involvement of foreign ground stations in collecting and distributing low bit rate data in near real time. ERS-2 data have an important role to play in the quest to ensure that products from spaceborne systems meet exacting requirements, enabling their use in global and regional monitoring activities. The ability to acquire data from sensors in orbit at the same time and observing the same geophysical parameters results in a powerful methodology (cross-calibration) that is used to tune instruments and retrieval algorithms. The current ability to compare data from ERS-2 and Envisat, for example, can be extended to involve Earth Explorer Missions such as Cryosat, SMOS, and MetOp.

Longevity of mission - excellence of engineering has led to long service so far and underpins the continuing role of the missions   Low-ozone event over Northern Hemisphere on 31 January 2002   ERS-2 SAR products are still highly valued because of their long-term consistency which is a function of regular and predictable acquisitions in a single operating mode. ERS-2 with its well-defined products and services has an important role to play in prepartion for GMES, building on the established customer base through the generation of policy-relevant services. Until the launch of GMES-dedicated missions, such as Sentinel, the retention of ERS-2 will provide the necessary additional capacity to maintain the uninterrupted data flow that is critical to the programme. ERS-2 Wind Scatterometer and GOME are unique instruments, not due for replacement until MetOp is launched in 2006. Even then, cross-calibration activites will necessitate continued ERS-2 operations during validation. ERS-2 has an ongoing role in fostering and sustaining international relationships. This is driven principally by the network of foreign ground stations receiving SAR data, and increasingly taking low bit rate data as well.

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry