German radar satellite TerraSAR-X – 15 years in space and still in perfect shape
June 14, 2022 | Radar data for remote sensing
German radar satellite TerraSAR-X – 15 years in space and still in perfect shape
The TerraSAR-X and TanDEM-X satellites in formation flight
The twin satellites in formation flight in their polar orbits around the Earth. TerraSAR-X was launched on 15 June 2007; TanDEM-X has been following it since 21 June 2010. Both radar satellites provide images using the Synthetic Aperture Radar technique, as well as interferometric radar images for three-dimensional mapping of Earth's surface.
The image shown here was created using a time series of 60 TerraSAR-X images acquired over a period of three years. The multiple images were processed into a false-colour image using DLR’s RADIAN software. Structures that have changed during this period are shown in red. Vegetation is coloured green and unchanged structures are shown in blue. The inner city of Munich can be seen with the Marienplatz in the centre, surrounded by the Altstadtring, which follows the former second city wall. To the left is the Hofgarten and the English Garden, below is the Isar with the Deutsches Museum on Museum Island and the European Patent Office opposite, visible as a bright cross-shaped structure. At the top of the image is the Theresienwiese, where the Spring Festival and the Oktoberfest take place, and to the right is the main railway station with the railway tracks.
Antarctica – ice dynamics and mass loss on the Ekblad Glacier
This image shows part of the Queen Elizabeth Range in the Transantarctic Mountains in October 2021. In the centre of the image is the Ekblad Glacier, which flows into the Ross Ice Shelf. The golden arch on the right shows crevasses around Cape Maude. TerraSAR-X provides information about the surface structure of the glaciers, the dynamics of the ice and, by allowing comparisons between repeated images, the way these are changing. This allows conclusions to be drawn about flow velocity and mass transport, which gives rise to findings about the melting of glaciers and the associated mass loss.
The German radar satellite TerraSAR-X celebrates its 15th anniversary in space on 15 June 2022.
TerraSAR-X allows researchers worldwide to document and better understand the changes on our planet.
TerraSAR-X serves two missions – the TerraSAR-X mission and the TanDEM-X mission for three-dimensional mapping of Earth's surface.
Experts are already working on the next generation of radar satellites for climate research and environmental observation – Tandem-L.
Focus: Space, Earth observation, radar technology
Fifteen years – who would have thought it? The German radar satellite TerraSAR-X, which was launched from the Baikonur Cosmodrome in Kazakhstan at 08:14 local time on 15 June 2007, was originally designed to last five and a half years – until the end of 2012. It has been delivering data of outstanding quality ever since, regardless of weather conditions, cloud cover and daylight levels. The scientific mission for TerraSAR-X and the satellite itself are operated by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR).
As it turns 15, TerraSAR-X can look back on 83,050 orbits of Earth, having travelled approximately 3.59 billion kilometres – a vast distance. If the satellite were travelling away from Earth in a straight line, it would have crossed the orbit of Uranus by late 2018 and would now be roughly midway between the orbits of Uranus and Neptune. At the grand old age of 15, TerraSAR-X is still in perfect shape.
Thanks to its robust design, combined with the highest measurement accuracy and stability, the satellite is still providing radar images that far surpass the original requirements for the mission. The high-resolution data and continuous view provided by TerraSAR-X enables researchers from all over the world to document and better understand the changes taking place on Earth, while facilitating the early detection of irreversible damage and pinpointing where intervention is needed. Such data provides an essential foundation for developing measures at a political and social level.
A data repository and research subject
Over its lifetime, TerraSAR-X has acquired more than 400,000 radar images, collecting 1.34 petabytes of data in the process. This is equivalent to 1,340,000 gigabytes or the streaming of around 270,000 high-definition feature films, which would take around 60 years to run through. The satellite’s legacy is becoming more comprehensive, more valuable and more widely used every day. More than 1100 leading researchers from 64 countries are now drawing upon and processing its data as part of 1875 ongoing research projects. Not only does the range of applications encompass the full spectrum of geosciences, including geology, glaciology, oceanography, meteorology and hydrology, but the radar data are also essential for environmental research, land use mapping, vegetation monitoring, and urban and infrastructure planning. Cartography, navigation, logistics, crisis management and defence and security also rely on TerraSAR-X data.
The satellite itself is the subject of research and development as well, particularly in the field of radar technology. With its flexible design, the radar system enables experiments to be conducted using new imaging modes such as a 'super wide angle' and 'super zoom', similar to a camera being fitted with different lenses. Officially referred to as 'WideScanSAR' and 'Staring Spotlight Mode', these were introduced during the course of the mission and then made available to users. The satellite continues to conduct radar experiments to test new techniques that might be used on future radar missions.
A third dimension with TanDEM-X
Since 21 June 2010, TerraSAR-X has been accompanied by the TanDEM-X satellite, which is almost identical in design. TanDEM-X and TerraSAR-X form the first reconfigurable Synthetic Aperture Radar (SAR) interferometer in space, recording precise height information for creating digital elevation models. This means that TerraSAR-X is now being used for two missions – the original TerraSAR-X mission and the TanDEM-X mission for three-dimensional mapping of Earth’s surface.
Despite its unprecedented longevity, the day will eventually come when TerraSAR-X is no longer able to fulfil its tasks. Resources such as propellant and battery capacity are steadily being depleted. However, if there are no major incidents, TerraSAR-X could remain in operation until the end of the 2020s.
Environmental observation in future – Tandem-L
With the TerraSAR-X and TanDEM-X satellite missions, DLR has set new standards in radar remote sensing. Its experts are already working on the next generation of radar satellites for climate research and environmental monitoring, in the form of Tandem-L, a highly innovative radar satellite mission. This could see Germany provide a system for the objective recording of the environment and the observation of environmental changes all over the world. The goal is to provide critical information to tackle highly relevant issues. For example, the latest report by the Intergovernmental Panel on Climate Change (IPCC) calls for the development of climate protection measures and the review of measures taken on a global scale, as a matter of urgency.
With Tandem-L, it would be possible to record a large number of dynamic processes in the biosphere, geosphere, cryosphere and hydrosphere with unprecedented quality and resolution. The new satellite constellation could provide up-to-date 3D imaging of Earth's entire landmass on a weekly basis and measure seven essential climate variables simultaneously. In doing so, Tandem-L would make a significant contribution towards a better understanding of processes that are now seen as drivers of local and global climate change.
About the mission
The DLR Microwaves and Radar Institute and Remote Sensing Technology Institute, together with the German Remote Sensing Data Center and the German Space Operations Center, form the SAR Center of Excellence. The institutes and facilities involved cover all areas of the TerraSAR-X mission, from sensor technologies and mission design to high-precision operational processing, all the way through to delivering refined end-user products. Together, these institutes and facilities are responsible for the construction and operation of the mission's ground segment and the coordination of its scientific utilisation.
The TerraSAR-X mission is being implemented on behalf of the German Aerospace Center (DLR), with funding from the Federal Ministry for Economic Affairs and Climate Action. It is the first German satellite to have been created as part of a Public–Private Partnership (PPP) between DLR and Airbus Defence and Space GmbH (formerly Astrium). Airbus Defence and Space shared the costs of the development, construction and deployment of the satellite. The Geo-Intelligence Programme Line at Airbus D&S (formerly Infoterra GmbH) is responsible for the commercial marketing of the data. Since 2016, the project has been operated under a continuation agreement with Airbus.
Contact
Bernadette Jung
Editor
German Aerospace Center (DLR)
Corporate Communications
Münchener Straße 20, 82234 Weßling
Tel: +49 8153 28-2251
Stefan Buckreuß
TerraSAR-X/TanDEM-X Mission management
German Aerospace Center (DLR)
Microwaves and Radar Institute
Münchener Straße 20, 82234 Oberpfaffenhofen-Weßling
