14. June 2017

Ex­cel­lence in space – 10 years of Ter­raSAR-X

The first TerraSAR-X image: Russia, west of Volgograd
The first Ter­raSAR-X im­age: Rus­sia, west of Vol­gograd
Image 1/4, Credit: DLR

The first TerraSAR-X image: Russia, west of Volgograd

The first Ter­raSAR-X im­age, de­liv­ered by DLR's pro­cess­ing sys­tem, shows a re­gion in the South Rus­sian steppe about 500 kilo­me­tres north-east of the Black Sea and about 50 kilo­me­tres west of Vol­gograd.
Reykjavík in the spotlight
Reyk­javík in the spot­light
Image 2/4, Credit: DLR

Reykjavík in the spotlight

Ice­landic cap­i­tal Reyk­javík: The Ter­raSAR-X im­age shows a de­tailed view of the coastal town. With the ‘Star­ing Spot­light’ mode, the satel­lite ob­serves the six by three kilo­me­tre ur­ban area and its spe­cial struc­tures. In the top sec­tion of the im­age, you can see the har­bor, or the great lake Tjörnin in the midst of the city. Promi­nent in one cor­ner of the lake is Reyk­javik's City Hall. Al­so the land­mark of Reyk­javík, the Hall­grím­skirk­ja (Church of Ice­land), ap­pears to the right of the lake in the cityscape.
Iceland: Infamous volcanoes
Ice­land: In­fa­mous vol­ca­noes
Image 3/4, Credit: DLR

Iceland: Infamous volcanoes

Vol­canic re­gion on the south coast of Ice­land: The Ter­raSAR-X im­age was ac­quired on 25 Novem­ber 2014, a few weeks af­ter the erup­tion of the Bar­dar­bun­ga sub­glacial vol­cano (cir­cle 2). The traces of vol­canic ac­tiv­i­ty are clear­ly vis­i­ble – a large la­va field be­low the Ask­ja vol­cano (cir­cle 3). An­oth­er ‘in­fa­mous’ glacier vol­cano is lo­cat­ed fur­ther west on the coast (cir­cle 1): The erup­tion of the Ey­jaf­jal­la­jökull in April 2010 and its sub­se­quent ash cloud brought the air traf­fic across Eu­rope to a stand­still for days. The radar im­age cap­tures the South coast of Ice­land in about 260 by 210 kilo­me­tres. For this pur­pose, the ‘Wide ScanSAR’ mode was used. It is the lat­est of a to­tal of five cap­ture modes of Ter­raSAR-X and al­lows the imag­ing of ex­treme­ly large ar­eas.
Determination of glacier movements
De­ter­mi­na­tion of glacier move­ments
Image 4/4, Credit: DLR

Determination of glacier movements

Us­ing Ter­raSAR-X da­ta, glacier move­ments can be pre­cise­ly de­ter­mined. The red cir­cles in­di­cate lakes un­der the ice.
  • The TerraSAR-X satellite has been in service for twice the planned time.
  • The data has been providing valuable insights regarding changes to the Earth's surface for the past 10 years.
  • Focus: Space, Big Data, Climate Change, Remote Sensing, Earth Observation

Designed to return unique images of the Earth for five years, the German radar satellite TerraSAR-X has outdone itself. The satellite has been in operation for twice that time – and there is still no end in sight to its service. Since its picture-perfect launch on 15 June 2007 from the Russian cosmodrome in Baikonur, the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) TerraSAR-X mission has exceeded all expectations.

"TerraSAR-X has stood for outstanding research and development performance and top-level satellite operation for 10 years. To this day, the mission continues to set standards in precision and image resolution. Thanks to its globally unique radar technology, TerraSAR-X has opened up a new era in remote sensing and paved the way for the equally successful follow-up mission, TanDEM-X. I am pleased that both satellites have been fully functional and efficient," emphasises Pascale Ehrenfreund, Chair of the DLR Executive Board.

TerraSAR-X and its twin TanDEM-X, which was launched three years later, have been flying in formation since 2010. Together, they generate the highest resolution three-dimensional images of the Earth's surface. To this day, the special mission concept of TanDEM-X, the first bistatic SAR interferometer in space, developed at the DLR Microwaves and Radar Institute, is one-of-a-kind.

"With the TerraSAR-X mission and its successor mission TanDEM-X, we have also entered new territory in industrial policy: TerraSAR-X was the first space project undertaken between DLR and the aerospace industry as a public-private partnership (PPP) on the initiative of the The DLR Space Ad­min­is­tra­tion with funds from the German Federal Ministry of Economic Affairs and Energy," added Gerd Gruppe, DLR Executive Board Member responsible for the Space Administration.

Big Data for Earth observation

The satellite has already delivered 303,714 images. The data is received via a global network of ground stations and processed and evaluated by experts at the DLR Earth Observation Center (EOC). Even the first analyses document indisputable details of climate change, including the retreat of glaciers across the globa. Approximately 1000 scientists from more than 50 countries are now using the data for their research – and demand is on the rise. The global radar images are of particular value to environmental and climate research. DLR ensures access to the images in the long term in the German Satellite Data Archive in Oberpfaffenhofen.

In this time, the Ger­man Space Op­er­a­tions Cen­ter (GSOC) has sent more than 1.85 million commands to TerraSAR-X, and an additional 1.4 million commands to control the orbiting TanDEM-X satellite. A particular challenge, both during the development and in operation, was and is the 'double-helix dance' of the two radar satellites. The tightest flight formation between TerraSAR-X and TanDEM-X was at a distance of 120 metres distance perpendicular to the direction of flight – at an average speed of 7.6 kilometres per second. The exceptional performance and success of the mission is not least down to the close interdiscplinary collaboration within DLR. In Oberpfaffenhofen, almost 100 staff from four DLR institutes have combined their expertise such that they have mastered the entire process chain of the TerraSAR-X and TanDEM-X mission for 10 years now.

The future

The exceptional lifetime of the satellite has been possible thanks to careful operation and robust construction. Only about half of the fuel supply has been consumed and the performance level of the batteries is approximately 72 percent, so the experts expect TerraSAR-X will continue to operate for another five years. The twin satellite TanDEM-X is also showing no signs of fatigue, meaning that more high resolution elevation images will be generated and the global data set enhanced by autumn 2017. The focus is on areas undergoing strong processes of change, and are therefore of particular scientific interest. These include the coastal regions of the Antarctic, Greenland and the permafrost regions, and the Amazon rainforest.

"The new images are also being used for the demonstration and preparation of the Tandem-L mission. With Tandem-L, DLR has designed a new satellite mission to observe how Earth is changing – for 10 years, on a weekly basis, at high resolution and in three dimensions. Such data will be of inestimable value for science and politics," explains Hans Jörg Dittus, DLR Executive Board Member for Space Research and Technology. With regard to the extent and effect of climate change, Tandem-L could provide important information that is still lacking – for improved scientific forecasts and the social and political recommendations for action that are based on this. The concept builds on the experience and exceptional success of the TerraSAR-X and TanDEM-X missions. If the mission proposal gets the 'green light', Tandem-L will take radar remote sensing into the next era of technology and applications in 2022.

With the X-Band SAR family, Germany has developed a globally recognised expertise and a unique selling point for decades. In order to ensure this leadership role in the future, the continuation of the X-Band family is being carried out at the DLR Space Administration. The future lies in an even higher resolution with wider observation swaths. This is intended to continuously provide the scientific, governmental and commercial stakeholders with data.

About the mission

TerraSAR-X has been delivered under contract to the German Aerospace Center, using funds provided by the German Federal Ministry for Economic Affairs and Energy. It is the first German satellite to be produced under a so-called public private partnership (PPP), between the DLR and Airbus Defence and Space GmbH (formerly Astrium). The use of TerraSAR-X data for scientific purposes is the responsibility of DLR (also responsible for the design and execution of the mission and control of the satellites). Airbus Defence and Space GmbH contributes to the costs of development, construction and deployment of the satellites. Infoterra GmbH, a subsidiary company established specifically for this purpose by the former Astrium GmbH, took over commercial marketing of the data.

  • Bernadette Jung
    Ger­man Aerospace Cen­ter (DLR)
    Pub­lic Af­fairs and Com­mu­ni­ca­tions: Oberp­faf­fen­hofen, Augs­burg, Weil­heim
    Telephone: +49 8153 28-2251
    Fax: +49 8153 28-1243
    Münchener Straße 20
    82234 Oberpfaffenhofen-Wessling
  • Prof. Dr.-Ing. Alberto Moreira
    DLR Ger­man Aerospace Cen­ter (DLR)
    Mi­crowaves and Radar In­sti­tute
    Telephone: +49 8153 28-2306
    Fax: +49 228 447-747
    Münchner Straße 20
    82234 Oberpfaffenhofen-Weßling
  • Prof. Dr. Michael Eineder
    SAR Sig­nal Pro­cess­ing
    Ger­man Aerospace Cen­ter (DLR)
    Earth Ob­ser­va­tion Cen­ter, Re­mote Sens­ing Tech­nol­o­gy In­sti­tute
    Telephone: +49 8153 28-1396
    Fax: +49 8153 28-1420
    82234 Weßling Oberpfaffenhofen
  • Dr.rer.nat. Edith Maurer
    Ger­man Aerospace Cen­ter (DLR)
    Space Op­er­a­tions and As­tro­naut Train­ing
    Telephone: +49 8153 28-3313
    Münchener Straße 20
    82234 Weßling
  • Michael Bartusch
    Project Man­ag­er Ter­raSAR-X / Tan­DEM-X
    Ger­man Aerospace Cen­ter (DLR)
    Space Ad­min­is­tra­tion
    Telephone: +49 228 447-589
    Fax: +49 228 447-747
    Königswinterer Straße 522-524
    53227 Bonn
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