The Argos-Next instrument developed by NASDA and CNES was switched on 29th of January 2003. The first images from POLDER 2, developed by CNES, were acquired 1st of February 2003 over Europe and Africa in eight spectral bands, from the visible to the near infrared, in natural and polarized light. Initial analysis shows that the data meet technical mission specifications.
A major milestone for the POLDER 2 instrument
POLDER 2 - CNES’s contribution to the ADEOS-II climate research programme, an international effort involving space agencies worldwide, including CNES, NASDA, NASA and NOAA - is now ready to begin its mission. The international scientific community will use POLDER 2 data to study the interactions between clouds, aerosols and the Earth’s radiation balance, and to gain a closer understanding of the role of marine phytoplankton and the continental biosphere in the carbon cycle. These new data will serve in particular to measure the impact of human activities on climate change in the light of rising greenhouse gas emissions.
In-orbit checkout operations being conducted by CNES and NASDA are proceeding according to plan and will continue until April 2003, when the system will enter operational service. The wide-field POLDER 2 instrument will subsequently be used to observe the polarization and the directional and multispectral signatures of reflected radiation around the globe.
Teams at the POLDER 2 ground segment, also developed and operated by CNES, will be responsible for programming the instrument, processing measurements and distributing data. The scientific processing algorithms were developed by CNES in collaboration with CEA/LSCE and LOA .
Verification of the instrument’s optical performance has begun and POLDER 2 level 1 data will be distributed starting in September 2003 once CNES teams have validated image quality. These data will be used to derive a range of geophysical products. In collaboration with its partner research laboratories CEA/LSCE and LOA, CNES will use ground-based and in-situ measurements, comparative data from other space-based sensors and various climatic and meteorological models to validate products. Validation is expected to be completed next year. Geophysical products will then be made available to the worldwide scientific user community.
Argos-Next – a new service to complement the Argos-2 mission
The Argos-Next mission, which complements and is fully compatible with the Argos-2 mission already operating on three satellites, offers a new downlink service. This service allows users to send messages to fixed and mobile terminals anywhere in the world. Two-way messaging capability will also pave the way for more sophisticated terminals able to receive and interpret messages from the satellites to give users information about sensor calibration, check and acknowledge data collection messages and let them switch terminals on and off to suit their needs.
In-orbit checkout operations being conducted by CNES and NASDA are proceeding according to plan. Tests on the uplink from terminals to the satellite have confirmed that the Argos-Next instrument was not damaged during the launch and that its performance on the ADEOS-II satellite is equivalent to other instruments developed by CNES already flying on U.S. satellites operated by NOAA.
Initial tests on the downlink from the satellite to terminals have shown that radiofrequency performance meets specifications and that message transmission controlled by the instrument’s software is functioning nominally.
In-orbit checkout will continue until April 2003 when the system will enter operational service. CNES subsidiary CLS will subsequently take over responsibility for processing and distribution of Argos-Next data for NASDA and CNES.
Development and operational use of the ground segment designed to support this improved Argos instrument is also giving CNES the opportunity to conduct in-flight validation of enhancements to the Argos system, to add an extra instrument to the system and to bring NASDA on board as a third partner in what was previously a bilateral programme managed jointly with NOAA
This service will also partly validate and give a foretaste of the third-generation Argos system (Argos-3) scheduled to fly starting in 2005 on the METOP series of satellites operated by Eumetsat, the European organisation for the exploitation of meteorological satellites, which will become the fourth partner to join the programme.
Eliane Moreaux :Tel : 18.104.22.168.33.44
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