The following synergistic use of PRISM with other sensors is expected: 
• AVHRR, AATSR and Meteosat for flux calculations, scale comparisons and correlation 
• OCTS for determination of emissivity of soil types, atmospheric correction 
• POLDER for atmospheric correction, polarisation 
• ASTER for determination of emissivities and temperatures at different scales 
• TIMS, TMS, AVIRIS (higher resolution airborne sensors and field campaigns) for detection of non 
linearity of fluxes and validation 
The key processes to be studied by PRISM are the energy, water, and biogeochemical fluxes. These fluxes are 
intimately linked to each other in many cases, necessitating an holistic approach to be taken for the utilisation 
of the data. The study of these fluxes over the land surface supports national and international programmes such 
as the WCRP, the IGBP, and ISLSCP. The secondary mission objectives are to assist resource management 
activities, and to study trace gas exchange fluxes. 
4. PRISM SPECIFICATIONS 
Some of the more important PRISM performance parameters are listed below: 
Spectral ranges: 
Spatial sampling : 
Swath width: 
Orbit: 
Data transmission: 
450nm - 2350nm at around lOnm resolution, 
at 3.8|im 1 band of about 0.6pm bandwidth 
8 - 12.3pm, 3 bands of 1pm bandwidth 
around 50m 
around 50km, with instrument depointing capability 
Sun-synchronous, polar orbit 
100Mbps by data selection and compression. 
The above parameters are still preliminary and will be refined during the establishment of the framework of a 
possible mission, and considering the requirements of the user community. 
5. FUTURE PLANS FOR PRISM 
With the guidance of ESA’s Science Advisory Group, the mission requirements and performance parameters will 
be defined in detail. These constraints will be subject to a technical pre-feasibility study carried out by European 
industry, aiming at the establishment of a technically feasible mission and system concept. In support of this 
activity several scientific studies are being initiated to substantiate the detailed requirements of the mission. 
The following scientific support studies are in progress or will be carried out in the near future: 
Studies in progress: 
• A study addressing spatial resolution aspects for the PRISM mission. 
• A study related to plant biochemistry for the PRISM mission. 
Studies to be initiated in the near future are: 
• Optimum spectral band configuration for the retrieval of temperature and emissivity by high resolution 
thermal infrared remote sensing. 
• Strategies for spectral and radiometric calibration of high resolution imaging spectrometer data. 
• Mission study of PRISM including the synergistic use with other sensors. 
• Exploitation of BRDF in high spectral resolution data over land surfaces. 
6. CONCLUSION 
In keeping with ESA’s continuing commitment to environmental remote sensing and its Earth observation 
strategy, the Agency intends to develop a high spatial and spectral mission dedicated to the support of land 
surface processes studies. 
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