TerraSAR-X image of the month – A game of mirrors

11 March 2013

2153 mirrors twist and turn at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) Experimental Solar Thermal Power Plant in Jülich, directing sunlight onto a 22-square-metre receiver. TerraSAR-X, the German radar satellite operated by DLR, can also detect the mirrors as they follow the Sun – from more than 500 kilometres above Earth. The reflections of the radar signals make the tower and mirror array appear as bright spots of light.

TerraSAR-X image of DLR Experimental Solar Thermal Power Plant in Jülich

Row upon row of mirrors stand in the 10-hectare field, automatically aligning themselves with the position of the Sun. The surface area of the mirrors totals 18,000 square metres, all used for converting solar radiation into power in the solar tower. But the smooth mirror surfaces also reflect most of the signals from TerraSAR-X back to the satellite. Metal components on the edges and the top of the 60-metre tower reflect the radar signals particularly well. The result is that, while many of the surfaces remain invisible to TerraSAR-X, the reflections are still sufficient for showing the contours of the tower and the majority of the mirrors in the radar image.

Developing Agriculture from the sky

13 March 2013 From 800 km high, Earth-observing satellites are assisting international development organisations with their work in developing countries. Satellites enable objective observations of the status of remote rural areas consistently over space and time.

Vietnam's Mekong Delta

The Mekong Delta in Vietnam is one of the world’s richest agricultural regions and due to the amount of rice produced there it is often referred to as Vietnam’s ‘rice bowl’. The crop feeds the rest of the country and produces enough to make Vietnam one of the world’s top rice exporters.
But the local agriculture – and, as a consequence, the nation’s economy – is threatened by sea level rise and the subsequent influx of salt water.
In order to identify long-term changes in rice cultivated areas and evaluate the effect of salinity intrusion on these areas, satellite data are being used to create land use and land cover maps for statistical analysis.
This is just one of five service trials within a collaborative project by ESA and the UN International Fund for Agricultural Development (IFAD), which finances agricultural development projects primarily for food production in the developing countries.
The other ESA–IFAD projects include land use, land cover and crop monitoring in Niger, Gambia, Botswana and São Tomé and Príncipe. Specialised European Earth observation service providers are also involved, including Deimos Engenharia (PT), Finnish Geodetic Institute (FI), GAF AG (DE), Geoville (AT) and Sarmap (CH).