The first earth observation satellite of the Sentinel series is still on the ground, but it and its followers will soon be delivering enormous amounts of data. The German Aerospace Center (DLR) will be ready. The ESA Processing and Archiving Centre (PAC) in Oberpfaffenhofen is linked up with the Copernicus Wide Area Network (WAN). This makes possible rapid and reliable high-speed access to the satellite data for the PAC at DLR. The Sentinel satellites complement the space components of Europe’s Copernicus programme – formerly Global Monitoring for Environment and Security (GMES). The data can be used for a multitude of environmental applications and for monitoring global change.
Smooth data transfer
Two redundant 10-gigabit optical fibre connections assure smooth satellite data transfer for the Copernicus programme. "This gives us not only rapid and reliable access to the data; it also allows enough scope for meeting ever-increasing requirements for storing enormous amounts of data in coming years", emphasizes Prof. Stefan Dech, Director of DLR’s German Remote Sensing Data Center. On behalf of the European Space Agency (ESA), the German Remote Sensing Data Center in Oberpfaffenhofen is setting up a processing and archiving centre (PAC) for Series 1 and 3 Copernicus satellites. The first Sentinel-1 satellite is scheduled for launch on 3 April 2014 from the Kourou space centre in French Guiana. This date will also mark the dawn of the Copernicus space component.
The radar instruments on the Sentinel-1 satellites will provide global images of the earth’s land surface and oceans — independent of weather and time of day. The land and ocean sensor on the Sentinel-3 satellite will record the earth’s entire surface within two days in 21 spectral channels and with a ground resolution of 300 metres. It provides parameters for such important global change indicators as vegetation dynamics, water quality and the carbon cycle. Sentinel-1 and Sentinel-3 further the continuous environmental monitoring which started in Europe in 1991 with the ESA satellites ERS-1, ERS-2 and ENVISAT. And also since 1991 DFD has been working as a processing and data centre on behalf of ESA for these first European earth observation satellites.
Long-term data storage and archiving
From the first Sentinel-1 satellite alone, some three terabytes of raw data will arrive in Oberpfaffenhofen daily from receiving stations in Europe and North America and via the European geostationary data relay system EDRS. Starting in spring 2015 a similarly large mass of data will be received in addition from the Sentinel-3 satellite. One year later each of these Sentinels will be augmented by a second satellite in the series, so that at DFD in Oberpfaffenhofen alone up to 10 terabytes a day will have to be archived and processed. In order to archive this much data, a new robot archive was put into operation last year at DFD. In its first stage of development it has a capacity of 50 petabytes. "This amount of data is equivalent to about five million HD-quality full-length cinema films“, explains Prof. Dech.
These raw data are converted at the PAC into digital products with the help of multiprocessor systems and distributed via the new 10-gigabit network to European and international users. The core Copernicus services – which are charged by the European Commission to evaluate the data for environmental and civil security purposes – represent an important user group. The data from Oberpfaffenhofen will also be used by scientists to map the environment and global change and by commercial bodies to develop new geoinformation products. Sentinel data is accessible free of charge to anyone. Distribution nodes for national user groups will also be established at national initiative.
DFD has taken the first step. The PAC at DFD in Oberpfaffenhofen is part of a European network including other PACs in Great Britain, France and Spain. These processing and archiving centres share responsibilities and are all connected through the Copernicus WAN, which T-Systems in Frankfurt was selected to design and implement. All work related to the establishment and operation of the Copernicus ground segment was contracted by ESA and financed by the European Commission.