TSX (TerraSAR-X) Mission

TerraSAR-X1 (also referred to as TSX or TSX-1) is a German SAR satellite mission for scientific and commercial applications (national project). The project is supported by BMBF (German Ministry of Education and Science) and managed by DLR (German Aerospace Center). In 2002, EADS Astrium GmbH was awarded a contract to implement the X-band TerraSAR satellite (TerraSAR-X) on the basis of a public-private partnership agreement (PPP). In this arrangement, EADS Astrium funded part of the implementation cost of the TerraSAR-X system.

In exchange, EADS Astrium/Infoterra received exclusive commercial exploitation rights for the TerraSAR-X data. The satellite is owned and operated by DLR, and the scientific data rights remain with DLR. The satellite has a design life of at least five years. TerraSAR-X is of SIR-C/X-SAR (1994) and SRTM (2000) heritage - DLR SAR instruments flown on Shuttle missions. ^{1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11)}

The science objectives are to make multi-mode and high-resolution X-band data available for a wide spectrum of scientific applications in such fields as:

• hydrology,
• geology,
• climatology,
• oceanography,
• environmental and disaster monitoring,
• cartography (DEM generation) making use of interferometry and stereometry.

The science potential of the mission is given by:

•  The high geometric and radiometric resolution (experimental 300 MHz Mode for very high range resolution)
•  The single, dual and quad polarization mode capability
•  The capability of multi-temporal imaging
• The capability of repeat-pass interferometry
•  The capability of ATI (Along-Track Interferometry)

The business goal in this venture is to establish a commercial EO (Earth Observation) market by Infoterra on a sustainable service concept to its customer base. Infoterra, a subsidiary of EADS Astrium, is comprised of Infoterra Ltd. in Farnborough, UK, and Infoterra GmbH in Friedrichshafen, Germany (a subsidiary of EADS Astrium GmbH). Infoterra has established a global distribution network with a range of service options for its customers.

A commercial goal is also to provide monitoring services for the European initiative GMES (Global Monitoring for Environment and Security). ^{12) 13) 14)}

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Spacecraft

The TerraSAR X-band satellite, built by Airbus Defence and Space Geo-Intelligence/Infoterra GmbH (formerly EADS Astrium GmbH, Friedrichshafen, Germany) employs a mission-tailored AstroSat-1000 bus (successor of Flexbus and LEOSTAR due to industrial merger - initially AstroSat-1000 was referred to as AstroBus) concept with a heritage of CHAMP and GRACE missions.

The hexagonal outer shape of the spacecraft, with a total height of about 5 m and a diameter of about 2.4 m, is mainly driven by the accommodation of the SAR instrument, the body-mounted solar array, and the geometrical limitations given by the Dnepr-1 launcher fairing.

The S/C bus design features a central hexagonal CFRP structure as the main load-carrying element. The cross-sectional view of Figure 6 illustrates the mounting concept of the radiator, solar array, and SAR antenna elements. Three sides of the hexagon are populated with electronic equipment, while the sun-facing side is additionally carrying the solar array.

The SAR antenna is mounted on one of the hexagon sides, which in flight attitude points 33.8º off the nadir. The other nadir-looking side is reserved for the accommodation of an S-band TT&C antenna, a SAR data downlink antenna - carried by a deployable boom of 3.3 m length in order to avoid RF interferences during simultaneous radar imaging and data transmission to the ground - and a Laser Retro Reflector to support precise orbit determination. The deep-space-looking surface is used for the LCT (Laser Communication Terminal) and as a thermal radiator. The total wet mass of the satellite is about 1230 kg.

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The solar array is of size 5.25 m², and triple-junction GaAs type solar cells provide an average orbital power of 800 W EOL. The attitude control system is based on reaction wheels for fine-pointing, with magnetorquers for desaturation, and a propulsion system also capable of attitude control in order to achieve rapid rate damping during initial acquisition.

Attitude measurement is performed with a GPS/Star Tracker system (MosaicGNSS) during nominal operation and a CESS (Coarse Earth and Sun Sensor) in safe mode situations, initial acquisition respectively (CESS is of CHAMP and GRACE heritage). A combination of an IMU (Inertial Measurement Unit) and a magnetometer serve to support rate measurements in all mission phases. In fine pointing mode, a pointing accuracy of 65 arcsecs is achieved (3 σ). Nominal attitude control follows a novel “total zero Doppler steering” law developed by DLR.

Precise orbit determination is performed with a dual-frequency GPS receiver and raw data post-processing on ground, permitting orbit restitution accuracies in the cm range. A set of high torque reaction wheels enables rapid rotation into the so-called SSL (Sun Side Looking) orientation which is used to acquire high-priority imaging targets. To point the SAR antenna in the SSL direction, a roll movement of 67.6º is required which is achieved in < 180 s.

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The MosaicGNSS receiver of EADS Astrium represents a fully space-qualified receiver that is specifically designed for high robustness and long-term use in a space environment. The receiver comprises a main electronic unit, a single L1 GPS patch antenna and an external low-noise amplifier. The signal correlation is performed in software and up to eight satellites can be tracked simultaneously with the current hardware configuration. A navigation filter ensures a smooth and continuous navigation solution even under restricted GPS visibility.

In the upcoming TerraSAR-X and TanDEM-X missions, the MosaicGNSS receiver supports the onboard timing and provides the basic orbital information for aligning the spacecraft with the ground track and nadir direction. MosaicGNSS navigation solutions will also be transmitted via an inter-satellite link between both spacecraft to support autonomous formation flying and collision avoidance. For precise orbit determination and baseline reconstruction, both spacecraft are equipped with dedicated dual-frequency GPS receivers IGOR (Integrated Geodetic and Occultation Receiver).

Furthermore, the MosaicGNSS receiver serves as an alternative for precise orbit determination in case the IGOR receiver would fail to work. To support this task, a full set of raw measurements is made available in the housekeeping telemetry in addition to the real-time navigation solution. The comprehensive measurement set and the availability of a geodetic grade reference receiver offer a unique opportunity to characterize the in-flight performance of the MosaicGNSS receiver. ¹⁷⁾

The spacecraft is equipped with a monopropellant hydrazine blow-down mode propulsion system for orbit maintenance and safe mode attitude control. A propellant mass of 78 kg is considered sufficient for almost 10 years of orbit maintenance support.

Onboard data handling: The newly developed ICDE (Integrated Control and Data System Electronics) system is being used as the central component for all avionics services. The ICDE core consists of two redundant 32-bit processor modules, implementing the ATMEL ERC32SC (Embedded Real‐time computing Core ‐ 32-bit Single Chip) processor, giving it a processing performance of more than 18 MIPS and enough memory capacity to handle full AOCS and data handling software tasks, leaving sufficient margins in performance and memory capacity for future extensions and redundancy concepts. A dedicated, hot-redundant reconfiguration module provides all necessary surveillance, reconfiguration, command and telemetry functions. The ICDE modules are cross-coupled, providing a fully redundant unit.

The ICDE provides the spacecraft and payload interfaces with the following standard link protocols: MIL-1553 bus, HDLC and SpaceWire. An optional GPS receiver module with optional star sensor processing fits seamlessly into the architecture. It is capable of acquiring and independently tracking up to eight GPS satellites and provides position, velocity and time.

The ICDE uses full duplex UART (Universal Asynchronous Receiver/Transmitter) interfaces to all ”intelligent” onboard equipment, except for the LCT experiment, where a MIL-STD-1553B bus is being used. The ICDE has a mass budget of 12-18 kg and a power demand of 15-30 W, depending on the configuration selected.

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The spacecraft design life is 5 years for operations with a goal of 6.5 years (de-orbiting is planned at the end of the useful lifetime).

Orbit: Sun-synchronous circular dawn-dusk orbit with a local time of ascending node at 18:00 hours (± 0.25 h) equatorial crossing, average altitude = 514.8 km (505-533 km), inclination = 97.44º, nominal revisit period of 11 days (167 orbits within revisit period, 15 2/11 orbits per day). The ground track repeatability is within ± 500 m per revisit period (repeat cycle). Due to its flexibility, TerraSAR-X can cover any point on Earth within a maximum of 4.5 days, and 90% of the surface within 2 days.

Spacecraft reentry (ESA requirement): At the end of its operational life the spacecraft orbit will be lowered to about 300 km (perigee) resulting eventually in enough air drag for a reentry (and a complete fragmentation and destruction of the S/C in the atmosphere).

RF communications: A standard S-band TT&C system with 360º coverage in uplink and downlink is used for satellite command reception and telemetry transmission. The uplink path is encrypted. Generated payload (SAR) data are stored onboard in an SSMM (Solid State Mass Memory) unit of 256 Gbit EOL capacity prior to transmission via the XDA (X-band Downlink Assembly) at a data rate of 300 Mbit/s. The X-band downlink is encrypted. The onboard SAR raw data are compressed using the BAQ (Block Adaptive Quantization) algorithm, a standard SAR procedure. The compression factor is selectable between 8/6, 8/4, 8/3 or 8/2 (more efficient techniques can only be applied to processed SAR imagery).

Both communication links are designed according to the ESA CCSDS Packet Telemetry Standard.

- The X-band antenna is mounted on a deployable boom 3.3 m in length (the only deployable item on the S/C) to prevent interference with the X-band SAR instrument. This arrangement enables simultaneous SAR observations and X-band downlink.

In preparation for the TanDEM-X mission, where the TerraSAR-X satellite will fly in close constellation with TanDEM-X (an identical S/C) for interferometric observations, the TerraSAR-X instrument is furnished with all necessary features for PRF and synchronization between the two spacecraft. In particular, there are 6 sync horns for the omnidirectional emission and reception of radar sync pulses.

Launch: The successful launch of TerraSAR-X took place on June 15, 2007, from the Russian Cosmodrome, Baikonur, Kazakhstan, on a Russian/Ukrainian Dnepr-1 launch vehicle with a 1.5 m long fairing extension. Launch provider: ISC Kosmotras, Moscow.

- The launch, originally planned for Oct. 31, 2006, had to be shifted several times after an unsuccessful launch of a rocket of the same type in the summer of 2006. The single cause of this launch mishap was discovered and properly corrected.

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A Data Repository and Research Subject

- Over its lifetime, TerraSAR-X has acquired more than 400,000 radar images, collecting 1.34 petabytes (1.34 x 10¹⁵ bytes) 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.

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 globe. Approximately 1000 scientists from more than 50 countries are now using the data for their research – and demand is on the rise.

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.

- During this time, GSOC (German Space Operations Center) 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 m distance perpendicular to the direction of flight – at an average speed of 7.6 km/s. The exceptional performance and success of the mission are not least down to the close interdisciplinary 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 life 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 per cent, so the experts expect TerraSAR-X will continue to operate for another five years.

The twin satellite TanDEM-X also shows no signs of fatigue, meaning that more high-resolution elevation images will be generated and the global data set will be 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.

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 recognized 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.

Mission Status

• June 14, 2022: 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. ¹⁸⁾After 15 years in operation, TerraSAR-X has completed 83,050 orbits of Earth, having travelled approximately 3.59 billion kilometres.

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• January 25, 2022: The TerraSAR-X mission had been operating nominally providing monostatic SAR imagery in its 15th year on orbit. Despite being well beyond its mission design life, the satellite was fully functional; it had enough consumables for a mission life until at least 2026. ¹⁹⁾

• April 22, 2021: The TerraSAR-X ESA archive collection consists of TerraSAR-X and TanDEM-X products requested by ESA-supported projects over their areas of interest around the world. The dataset regularly grows as ESA collects new products over the years. ²⁰⁾  TerraSAR-X/TanDEM-X Image Products can be acquired in six image modes with flexible resolutions (from 0.25m to 40m) and scene sizes. Thanks to different polarimetric combinations and processing levels the delivered imagery can be tailored specifically to meet the requirements of the application. The following list delineates the characteristics of the SAR imaging modes that are disseminated under ESA Third Party Missions (TPM): StripMap, SpotLight, Staring SpotLight, High-Resolution SpotLight, ScanSAR, WideScanSAR. The following list briefly delineates the available processing levels for the TerraSAR-X dataset: SSC (Single Look Slant Range Complex) in DLR-defined COSAR binary format, MGD (Multi Look Ground Range Detected) in GeoTiff format, GEC (Geocoded Ellipsoid Corrected) in GeoTiff format, EEC (Enhanced Ellipsoid Corrected in GeoTiff format.

• February 1, 2019: The Thwaites Glacier, one of the most fragile glaciers in western Antarctica, is melting inexorably into the Amundsen Sea at an ever-increasing rate. Until now, it has been responsible for approximately four per cent of the global rise in sea level and will cause the oceans to rise by over 65 centimetres in future as its remaining ice melts. With the German radar satellites TerraSAR-X and TanDEM-X, it was possible to observe Thwaites Glacier and other polar regions at regular intervals, with high resolution and in three dimensions. Scientists from DLR ( German Aerospace Center) have generated special TanDEM-X elevation models to better understand and predict the melting processes and changes occurring on Thwaites Glacier. The results of the NASA-led study have now been published in the scientific journal Science Advances. ^{21) 22)}

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- There is a gigantic, 350-meter cavity in the floor of the Antarctic glacier, with the penetrating seawater continuously eating further into the ice. Experts have long suspected that Thwaites is not firmly attached to the bedrock beneath it, but the size of the cavity and the formation of subglacial channels was as surprising as it was alarming. Satellite data acquired by the partners from the United States, Germany and Italy revealed that a total of 14 billion tons of ice have already been washed out, mainly in the last three years. The melt rate was calculated based on TanDEM-X images.

- In addition, the TanDEM-X elevation models reveal the glacier's special dynamics. The changes in the ice surface elevation were measured with millimetre accuracy, allowing important conclusions to be drawn about the underlying melting processes. Scientists thus discovered that although the glacier surface is rising, the overall thickness of the ice is decreasing. For the detailed time series analyses, the DLR experts ordered a total of 120 TanDEM-X images over the period from 2010 to 2017. A time series of elevation models were created from these using the global TanDEM-X elevation model. The highly accurate determination of the glacier's structure is achieved thanks to high-precision interferometric processing, geocoding and calibration of TanDEM-X images, which was implemented at the DLR Microwaves and Radar Institute. New radar remote sensing technologies and methods make it possible for scientists to conduct more targeted research into critical climate processes and further improve predictive models. The latest findings on the development of Thwaites Glacier provide a valuable guide for climate and environmental research.

• June 2018: The missions TSX (TerraSAR-X) and TDX (TanDEM-X jointly share the same space segment consisting of two almost identical satellites orbiting in close formation. They are operated using a common ground segment, that was originally developed for TSX and that has been extended for the TDX mission. A key issue in operating both missions jointly is the combination of the different acquisition scenarios: TSX requests are typically single scenes for individual scientific and commercial customers, whereas the global DEM as well as science products require a global mapping strategy. Thus the TSX mission goal is retained and served by both satellites. TSX and TDX reached their nominal lifetime at the end of 2012 and 2015, respectively. Therefore it is worth having a look at the status of the irretrievable on-board resources. Especially the propellant and the battery status are crucial factors determining the future progress and remaining duration of the mission.

- By June 2018 TSX will have exceeded its nominal lifetime by 5.5 years and TDX by 2.5 years. Fuel and battery status are considerably better than predicted. The radar performance and calibration of the individual satellites are still within specification or better and no indication of any degradation is noticeable at the moment. As both satellites were still working very well and had plenty of resources left, they planned to continue the mission beyond 2020 with a focus on selectively updating and improving the global TanDEM-X DEM and generating a global Change DEM as a self-contained product.

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• February 9, 2018: The satellite duo, TerraSAR-X and TanDEM-X, continue to orbit in close formation to make bistatic observations for scientific applications. In addition, observations are being made to fill small areas in the DEM and to improve the quality of the data. Furthermore, observations are being conducted to capture topographic changes. ²⁴⁾ Both satellites have used their consumables frugally; each spacecraft spent so far somewhat less than half a tank volume of hydrazine; the batteries are in good operational condition, and the quality of the radar imagery remains excellent since the start of the mission. The project expects a continuation of operational services of the two missions to at least 2020, subject to unforeseen events. A paper has been published providing forest maps on the basis of interferometric TanDEM-X data. ²⁵⁾

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- The TanDEM-X Forest/Non-Forest Map project, led by DLR/MRI (Microwaves and Radar Institute), aims to create a global classification mosaic of forested and non-forested areas using TanDEM-X bistatic InSAR (Interferometric Synthetic Aperture Radar) data. This data was collected during the generation of the global DEM (Digital Elevation Model) between 2011 and 2015 in stripmap single polarization (HH) mode. The project uses a global dataset of quick-look images with a ground resolution of 50 m x 50 m to manage computational demands. Various observables provided by TanDEM-X, including calibrated amplitude, bistatic coherence, and DEM height, are used for classification. The volume correlation factor, derived from interferometric coherence, helps identify vegetated regions by quantifying decorrelation caused by multiple scattering within vegetation volumes. A fuzzy multi-clustering classification approach is applied to each acquired scene, with cluster centers defined based on the geometric acquisition configuration.

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 • June 15, 2017: the TerraSAR-X spacecraft and its payload were 10 years on orbit. 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. ²⁷⁾

- 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. Developed and constructed by Airbus Defence and Space teams from Friedrichshafen for the DLR (German Aerospace Center), the satellite orbits at a height of 514 km and provides radar imagery to a wide variety of scientific and commercial users. ²⁸⁾

Figure 15: TerraSAR-X - 10 Years at Your Service and ready for more. On 15 June 2017 we celebrate the 10th anniversary of the launch of our high-resolution radar satellite TerraSAR-X. The satellite has not only achieved double its service life, having orbited the Earth 55,459 times and travelled 2.4 billion kilometers, all while boasting 99.9 percent availability, it has also delivered an outstanding performance. While celebrating this great achievement, Airbus is also continuing to shape the future with the upcoming new very high-resolution optical constellation, futures HAPS services and the SpaceDataHighway (video credit: Airbus DS, Published on 15 June 2017)

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• January 13, 2017: The satellite duo, TerraSAR-X and TanDEM-X, continue to orbit in close formation to make bistatic observations for scientific applications. Both satellites have used their consumables frugally; each spacecraft spent so far about half a tank volume of hydrazine; the batteries are in good operational conditions, and the quality of the radar imagery has remained excellent since the start of the missions. The project expects a continuation of operational services of the two missions until about 2020 — these predictions depend of course on the assumption that no unanticipated events occur. After all, in June 2017, TerraSAR-X will be 10 years on orbit. ³⁰⁾ The measurement of the polar regions by TSX/TDX is so precise that glacier movements can be seen in the centimetre range, and changes in elevation caused by ice melting are measured in the meter range. Initial studies have shown that in some regions, glaciers are losing up to 30 m thickness per year in the area of the glacier tongues.

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• October 17, 2016: The German satellite duo TerraSAR-X and TanDEM-X have consistently delivered one-of-a-kind Earth observation data since 2007 and 2010, hence shaping the international research landscape. Now, scientific users from across the globe have gathered for the TerraSAR-X and TanDEM-X Science Meeting at DLR (German Aerospace Center) in Oberpfaffenhofen, where they will discuss the results obtained from the data and define requirements for future remote sensing technology. ³¹⁾

• July 2016: Since the launch of the TDX (TanDEM-X) mission in 2010, the two missions TSX (TerraSAR-X) and TDX share a joint space segment consisting of both TSX and TDX and a common ground segment which was first developed for TSX and had been later extended for TDX. While TanDEM-X uses both satellites (nominally one in receive-only mode) for an acquisition, TerraSAR-X data are acquired by either one of the two satellites. It is this sharing of one ground segment which necessitated ongoing updates of the TerraSAR-X ground segment in accordance with the TanDEM-X mission constraints. ³²⁾ Table 2 summarizes the acquisition mode portfolio. In response to a growing demand for larger coverages at moderate resolution and for higher resolution with more radiometric looks, the original portfolio was extended by the new Wide ScanSAR and Staring Spotlight mode in 2013. Users can directly order future TanDEM-X data takes and request products generated from archived Level 0 data through catalogue ordering. The mission offers different acquisition modes, including StripMap data in fully polarized and Along-Track Interferometric configurations, although these are used for specific campaigns. The Dual-Receive Antenna (DRA) configuration, while offering redundancy, affects the acquisition and downlink timeline, preventing data replay during acquisition. To address limitations in the availability of ATI products, an experimental mode called ATIS, using a single antenna, is also offered. Users can access data from these experimental modes through catalogue orders.

Table 2: TerraSAR-X acquisition modes

Mode	Coverage Azimuth x Range (km2)	Resolution Class (m)
ScanSAR Wide (SCW)	200 x (194–266)	40
ScanSAR (SC)	150 x 100	18
StripMap (SM)	50 x 30	3
Spotlight (SL)	10 x 10	1.7 - 3.5
High-Resolution Spotlight (HS)	5 x 10	1.4 - 3.5
300 MHz High-Resolution Spotlight (HS 300)	5 x (5-10)	1.1 - 1.8
Staring Spotlight (ST)	(2.5 – 2.8) x ~ 6	0.24 azimuth, 1.0 range

 

​​- ​​The science phase of the mission began in September 2014 when TanDEM-X moved away from TerraSAR-X, maintaining a distance of 76 km behind TerraSAR-X. Users can directly order data from all modes, and once data is archived, catalog ordering is possible. The mission has adopted various flight configurations, including pursuit monostatic, bistatic, and dual-receive antenna modes, each with its own implications on data acquisition and quality. To ensure data quality consistency, measures are taken to align the performance of TanDEM-X (TDX) with TerraSAR-X (TSX), including roll angles and time delays. TSX may also acquire data when TDX exceeds certain baseline thresholds. Simultaneous operation of TSX and TDX instruments in active mode increases imaging opportunities and reduces conflicts among acquisition hot spots. Data from PSM TanDEM-X acquisitions can be processed into SAR products, similar to TerraSAR-X products, with some differences in performance and characterization parameters. Near Real-Time (NRT) data processing has been improved over the years, allowing for quick data dissemination, including support for maritime applications like ship and oil detection. The mission features flexible operational functions between TSX and TDX, and the satellites are designed for an extended lifetime.

- The mission has made significant progress in generating a global Digital Elevation Model (DEM), with more than 80% of land surfaces covered by March 2016. The system undergoes continuous monitoring and verification for accuracy. Compared to SRTM the TanDEM-X DEM features a much lower percentage of void areas, especially in desert areas, a result of the re-acquisition at lower incidence angles and hence better SNR. Further details on the global DEM quality can be found in reference ³⁴⁾ Beyond the generation of a global TanDEM-X DEM as the primary mission goal, a dedicated science phase was aimed at demonstrating the generation of even more accurate DEMs on local scales and applications based on along-track interferometry and new SAR techniques, with a focus on multistatic SAR, polarimetric SAR interferometry, digital beamforming and super-resolution. As both satellites are still working very well and have plenty of resources left, an agreement to continue the mission beyond 2015 was concluded between DLR and Airbus Defence & Space. Acquisition of interferometric data for and generation of local DEMs of even higher accuracy levels (posting of 6 m and relative vertical accuracy below 1 m) is the key objective for this new mission phase. If the baseline geometries are suitable for further scientific experiments will be included in the timeline as well.

​• November 30, 2015: Based on the trusted collaboration in space, CSA (Canadian Space Agency) and DLR (German Aerospace Center) have announced the funding of six major research projects in the domain of Emergency Response and Safety of Operations. DLR has awarded Airbus Defence and Space with two of them. ³⁵⁾ In collaboration with MDA (MacDonald Dettwiler and Associates, Ltd.), the first project will examine man-made changes on land using multi-frequency SAR satellite data. The methods developed throughout this project will monitor the changes’ impact on the environment including new buildings, roads, forests, and surface movements due to industrial activities such as mining. For the second project, Airbus Defence and Space will work with C-CORE to investigate the synergistic use of X-and C-band SAR data for tactical ship route planning in Arctic waters, its objective being to monitor the sea ice situation along shipping routes in the north. Both Canadian partners receive funds from CSA. Taking benefit from combining both missions - the German TerraSAR-X and the Canadian RADARSAT-2 satellites.

• July 30, 2015: Airbus Defence and Space, owner of the commercial distribution rights for TerraSAR-X data, and ESA have signed a contract securing the continued supply of TerraSAR-X data for the Copernicus Data Warehouse. The agreement is valid until the end of 2020, thus continuing the successful cooperation between Airbus Defence and Space and ESA for the provision of TerraSAR-X data to public institutions across Europe in place since 2008. TerraSAR-X has been a key data source, particularly for activities addressing emergency and security-related issues, reliable monitoring needs, and land cover change, both in Europe and beyond. It's unique reliability and high accuracy make it an ideal data source within ESA's multi-mission approach. The agreement includes the provision of archived and newly acquired TerraSAR-X data for the Copernicus core datasets in the area of maritime monitoring, as well as additional datasets for further maritime applications, particularly sea ice monitoring.

• February 2015, the TanDEM (TanDEM-X and TerraSAR-X) missions are operating nominally, supporting the science mission. The new science phase started in September/October 2014, applies to both missions of the formation, TerraSAR-X and TanDEM-X, and is planned to last until the end of 2015. ³⁶⁾The first part of the science mission, from Sept. 20, 2014, to the end of March 2015, is the so-called “Pursuit Monostatic Phase“, in which the TanDEM-X spacecraft is flying at a distance of 76 km behind its twin, TerraSAR-X. Each spacecraft acquires monostatic data of the same area which are then interferometrically ground-processed. At the end of March, the formation changed again; the “Bistatic Phase” started in which bistatic acquisitions with a large horizontal baseline (up to 3600 m) were taken up to September. After a drift phase of about a month, the bistatic phase continued in October with a small baseline of ~250 m, until the end of the year. Independently from the science mission, the TerraSAR-X mission (generation of non-interferometric SAR products), is being served in parallel from both spacecraft.

• October 10, 2014: After four years of successful data acquisition for the new global topographical map of Earth, the Science Phase is beginning. The radar satellite TerraSAR-X has been orbiting the Earth since June 2007; in June 2010 its twin, TanDEM-X, followed it into space. For almost four years, the two satellites have been operated in a close flight formation by DLR (German Aerospace Center). During this time, the satellites have been acquiring data to generate a new global topographical map of the Earth. ^{37) 38)} The goal of the TanDEM-X mission is to produce a highly precise, three-dimensional image of the Earth with uniform quality and unprecedented accuracy. For large parts of the Earth, there currently exist only approximate, inconsistent or incomplete elevation models derived from different data sources and collection methods. TanDEM-X is filling in these gaps and providing a homogeneous elevation model to be used as an indispensable basis for numerous commercial applications and scientific investigations.

• September 17, 2014: The initial preparations for the science phase began with the transition to the new formation on 17 September 2014. TanDEM-X moved away from TerraSAR-X and has been flying at a distance of 76 km behind its twin since 20 September 2014. This has resulted in a time delay of 10 seconds. Since the Earth rotates at approximately 500 m/s at the equator, the orbit of TanDEM-X has also had to be displaced laterally by 5 km so that both satellites are imaging the same area (footprint) on the surface. TanDEM-X continues to follow a helical orbit. Unlike the imaging for the DEM (Digital Elevation Model) of the Earth, the helix will not be adhered to for weeks at a time; instead, significantly greater variations will be permitted. The distance between TanDEM-X and the nominal orbit of TerraSAR-X will vary between 0 and 1000 m over the next five months. The aim is to continue to operate both satellites using interferometry, to enable three-dimensional imaging of the surface of the Earth to continue. After changing the orbit of TanDEM-X in recent weeks, the two satellites are being operated independently of one another, in what is known as 'Pursuit Monostatic Mode'.

- The advantage of this new orbital configuration is that the distance between the satellites – the baseline – can be made substantially more flexible. In the new orbital configuration, data for elevation models can be generated with an elevation accuracy of a few tens of centimetres, for example. This opens up new applications in the areas of the geosphere, cryosphere and hydrosphere. This data is unique and will be used in the investigation of volcanic eruptions, the melting of ice as well as, for example, tomographic imaging of cities. The orbital configuration will be changed again in the spring of 2015 to enable other applications and demonstrations. The imaging for the DEM was completed, with the exception of a few images. Final DEM tiles for more than a quarter of the land area – for example, for the flat areas of Australia, North America, Siberia, South and West Africa and South America – have already been processed. The success of TanDEM-X forms the basis for the development of innovative radar technologies. The aim is to achieve a significantly higher imaging capability, which will exceed that of TanDEM-X by a factor of 100. While TanDEM-X only enables one global image of the Earth to be acquired per year, Tandem-L will image the entire landmass of the Earth at a higher resolution twice a week. Hence, Tandem-L will be able to capture dynamic changes on the surface of the Earth with the required imaging repetition frequency and provide urgently needed information for solving topical scientific questions involving the areas of the biosphere, geosphere, cryosphere and hydrosphere.

• September 16, 2014: The lava outflow on the Holuhraun field northeast of Iceland's Bardarbunga volcano continues unabated. The lava field has grown to cover an area greater than 25 km². In this satellite image, the extent of the lava field is revealed using different colours. ³⁹⁾Researchers from DLR/IMF (Institut für Methodik der Fernerkundung), Oberpfaffenhofen are continuing to monitor the area. Radar images can be used to analyze changes to Earth's surface throughout the entire process. To create this image, three sets of data were acquired at different times, but from the same viewpoint, and then superimposed. They date from 13 August, 4 September and 15 September 2014 and were acquired by the German radar satellite TerraSAR-X. Yellow shows the growth of the lava field between 13 August and 4 September; red shows the expansion between 4 and 15 September. It is obvious that the area has doubled in the shorter second period. A second eruption area can also be seen as a small red spot in the lower right corner of the image.

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• September 10, 2014: Bardarbunga, (Bárðarbunga) in Iceland, one of the largest volcanoes in Europe and located beneath the biggest glacier in Europe, became active again in mid-August. For several years now, DLR researchers have been keeping a close eye on Bardarbunga and the system of volcanoes associated with it - an enormous network of subterranean magma channels, vents and craters. TerraSAR-X has now provided important data on the volcano's latest activity. ⁴⁰⁾Activity in the Bardarbunga volcano system began with earthquakes having magnitudes of up to of 5.7 on the Richter scale, indicating that magma beneath the surface was moving and rising. On 29 August, a lava flow escaped from a breach in the Holuhraun lava field to the north of the glacier - an ice-free area. The Holuhraun lava field has now grown to cover an area of over 19 km².

- The image shown here covers an area of approximately 30 km x 50 km, and the recently ejected lava covers an area of roughly 10 km². The brighter areas, which are also highlighted in red for better visibility, indicate changes in amplitude (the intensity of the radar signals returned to the satellite). Since the rough surface of freshly-cooled lava reflects the radar signals back very strongly, it appears bright and is easily visible on the lava flow at the lower right in the image or on the two arcs at the right edge of the image (the northern edge of Vatnajökull). Smooth surfaces, such as water, reflect the incoming radar signals away from the satellite and so appear dark on the images.

​• June 15, 2014: TerraSAR-X was 7 years on orbit, operating nominally. Nominal mission operations applied also to the TanDEM-X mission. Meanwhile, TerraSAR-X has reached its nominal lifetime by the end of 2012, the TanDEM-X mission would reach it by the end of 2015. The current status of the TerraSAR-X spacecraft resources allows at least three years of an extra lifetime until the end of 2015, providing five years of joint operation with its twin satellite in order to accomplish the TanDEM-X mission. The radar performance and calibration of the individual satellites are still within specification or better. ⁴¹⁾

Table 3: Comparison of TerraSAR-X versus TanDEM-X calibration status

Parameter	TerraSAR-X	TanDEM-X
Internal calibration: Instrument drift (Amplitude/Phase) TRM characterization (Amplitude/Phase)	≤ 0.15 dB / ≤ 0.5º < 0.2 dB / < 2º	≤ 0.1dB / ≤ 0.85º < 0.2 dB / < 2º
Geometric calibration: Pixel location accuracy (azimuth/range)	12.1 cm / 10.7 cm	9.2 cm / 11.0 cm
Antenna pointing: (azimuth / elevation)	0.01º / 0.04º	< 0.02º / < 0.02º
Antenna Model: shape and gain-offset	≤ ±0.2 dB	≤ ±0.2 dB
Radiometric calibration: Radiometric stability Relative radiometric accuracy (strip/scan) Absolute radiometric accuracy (strip/scan)	0.15 dB / (6 years) 0.16 dB / 0.27 dB 0.34 dB / 0.40 dB	0.15 dB / (6 years) 0.2 dB / 0.3 dB 0.48 dB / 0.52 dB

- New imaging modes (introduced in July 2013):

- To meet the increasing demand for higher resolution and more detail, as well as increased coverage, the capabilities of the TerraSAR-X mission were extended by implementing two new modes. The flexible instrument design allows such upgrades even with the satellites in orbit. A Wide ScanSAR product with an extended swath width of up to 260 km and a Staring Spotlight product with an intrinsic azimuth resolution of 24 cm, which is being traded for a considerably improved radiometric resolution, have been added to the product portfolio. The staring Spotlight mode even further increases the high geometric resolution of the standard High-Resolution Spotlight product. By widening the azimuth beam steering angle range, thereby extending the synthetic aperture, an azimuth resolution of 0.24 m can be achieved. It is available as single polarization 300 MHz range bandwidth variant. The scene extent varies between 2.5 km and 2.8 km in azimuth and 4.6 km to 7.5 km in range. The standard ScanSAR covers a 100 km wide swath. In order to meet the increasing demand for wider swath coverage, the new Wide ScanSAR mode was introduced. This new ScanSAR variant offers a 195 km to 266 km wide swath by employing 6 specific beams with a reduced azimuth resolution of 40 m and a variable range bandwidth of 50 MHz to 100 MHz.

Table 4: Comparison of High-Resolution Sliding Spotlight (HS) and Staring Spotlight (ST) product parameters

Parameter	Sliding Spotlight (HS, 300 MHz)	Staring Spotlight (ST, 300 MHz)
Scene size	Azimuth: 5 km Ground rage: 10 km – 5 km	Azimuth: 2.5 km - 2.8 km Ground range: 7.5 km - 4.6 km
Full performance including angle range	20º - 55º	20º - 45º
Data access incidence angle range	15º - 60º	15º - 60º
Azimuth steering angle	±0.7º	±2.2º
Azimuth resolution	1.1 m (single polarization)	0.24 m (single polarization)
Ground range resolution	1.1 m – 1.8 m	0.9 m – 1.8 m
Polarizations	HH or VV (single)	HH or VV (single)

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Table 5: Comparison of nominal (four beams) and wide ScanSAR (six beams) product parameters

Parameter	Four Beam ScanSAR	Six Beam ScanSAR
Number of subswaths	4	6
Scene size (Nominal L1b product length)	Azimuth: 150 km Ground range: 100 km	Azimuth: 200 km Ground range: 266 km to 194 km
Full performance incidence angle range	20° - 45°	15.6° - 49°
Data access incidence angle range	15° - 60°	15.6° - 49°
Elevation beams	27	10
Azimuth resolution	18.5 m	40 m
Range bandwidth	100 and 150 MHz	81.25 to 31.25 MHz
Ground range resolution	1.70 m - 3.49 m	6 m - 10 m
Polarizations	HH or VV (single polarization)	HH, VV (single polarization), VH (cross polarization)

 

-The new operational TerraSAR-X 6 beam Wide ScanSAR mode with cross-track coverage of up to 260 km shows excellent results in NESZ, ambiguity ratios and resolution. Taking into account, that during the design of the satellite, only swath widths of 100 km were required, the challenging task was achieved with an iterative optimization approach. The outcome is a very impressive achievement for the mission. ⁴²⁾Both GEOINT (Geospatial Intelligence) and IMINT (Image Intelligence) increasingly make use of high-resolution SAR data. The new TerraSAR-X Staring Spotlight mode provides the highest spatial resolution presently available on a commercial spaceborne SAR system. The TerraSAR-X Staring Spotlight mode provides a means to assess man-made objects more precisely. Image measurements of size, shape and position are more accurate, target interpretation is more reliable. ⁴³

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• June 2014: LTSM (Long-Term System Monitoring) of the TerraSAR-X and TanDEM-X missions. In order to guarantee a stable quality of SAR products and to monitor the correct operation of the entire SAR systems, both systems are regularly monitored. LTSM covers the SAR system-related parts of the combined TerraSAR-X and TanDEM-X system (space & ground segment). The detection of long-term SAR system performance changes is the primary subject of the LTSM. The objective of LTSM is the collection and supply of information that can be used to initiate (if needed and feasible) dedicated actions to maintain the specified SAR product quality. Furthermore, the LTSM can help to reveal the causes for events that seem to be by chance (e.g. non-reproducible failure in command execution) by analyzing similar cases (detection of coincidences with other events, operational or environmental conditions). ⁴⁴⁾

Instrument operations: Continuous monitoring of both SAR instruments in orbit is required to detect degradations of the satellite hardware and to compensate them by adapting the respective parameters. Therefore, the instrument status of TSX-1 and TDX-1 is checked regularly. The main source is the telemetry data of the satellites, downlinked via the S-band. In addition, complementary ground segment data is evaluated in order to derive regular statistics on instrument load (commanded and executed acquisitions) etc.

Monitoring of TRMs (Transmit/Receive Modules): For characterizing individual TRMs simultaneously a method based on orthogonal codes is applied. Regular antenna health checks, based on the automated acquisition of special system datatakes at regular intervals, monitor the TRM transmit and receive gain, as well as transmit and receive phase for both instruments in-flight. Possible degradation or drifts can be found by depicting gain and phase trends over time. All active TRMs work within the established limits and no trend can be observed, indicating the stability of the TSX-1 instrument and the TRM settings, respectively. The amplitude deviation (1σ) stays below 0.1 dB and the phase deviation is under 1° for all TRMs.

​Monitoring of front-end temperatures: This activity shows that the instrument is operated in its space-qualified thermal conditions. Figure 32 shows the daily maximum temperatures of the 12 front-end antenna panels of each instrument. The measured panel temperatures are far from the limit temperature of 30°C for nominal performance. The temperature peak observed in both plots shows the instrument's thermal behaviour in extreme conditions during a Hot-Cold Test executed during the TDX-1 Commissioning Phase.

​Instrument performance: SAR performance parameters are monitored continuously in order to provide long-term statistics and to prove the quality of the SAR data products. In the first step, each nominal datatake is checked immediately after the screening of the raw data. In this screening process, a number of limit checks are performed on selected statistical performance parameters. Limit violations will trigger immediate notifications.

Doppler centroid: SAR image quality is affected by the Doppler centroid. The main contribution, an effective squint angle due to Earth rotation, is compensated by Total Zero Doppler Steering. The residual Doppler centroid is estimated for each datatake by the operational SAR processors. As the Doppler centroid frequency of the SAR signal is related to the location of the azimuth beam centre, the evaluation of Doppler estimations over a number of datatakes can reveal antenna mispointing in flight direction. This sensitivity of the SAR system has been exploited in the monostatic commissioning phase of the satellites. The mean Doppler values are concentrated around 0 Hz mainly (95 % of the total acquisitions) in a tube of ±120 Hz, providing a stable image quality over the mission time. The data collected over the operational mission time does not show any trends. Outliers could be identified as non-nominal satellite conditions (e.g. GPS anomalies).

- The measurements and the extended analyses performed for long-term system monitoring of both SAR systems TerraSAR-X and TanDEM-X show very high stability of the instrument performance. Since the launch of the respective satellite, no degradation in the performance of both instruments has been observed. All parameters show a constant behaviour. Hence, by all these measurements performed for LTSM, it can be concluded that TerraSAR-X and TanDEM-X could be characterized and adjusted precisely, achieving the end a highly accurate and stable SAR System (Ref. 44).

• January 09, 2014: For ten days, 74 scientists and tourists were trapped in the Antarctic on board the Russian Akademik Shokalskiy research vessel. Strong winds had driven ice floes into a bay, blocking the ship's advancement. High-resolution satellite data of TerraSAR-X provided by DLR (German Aerospace Center) helped to assess the ice conditions at the location. ⁴⁵⁾In pack ice, the situation can change quickly when the wind shifts. This is why researchers from the DLR Earth Observation Center (EOC) use up-to-date, high-resolution images from the Earth observation satellite TerraSAR-X to provide the crew of the research vessel with up-to-date information regarding the ice conditions. The German radar satellite operates in a variety of modes to permit imaging with varying swath widths, resolutions and polarizations.

- Seeing through clouds and darkness, the satellite is able to observe the ocean and frozen waters from an altitude of around 500 km, providing a swath width of 30 km. To do this, it emits microwaves that are reflected back to the satellite in a way that depends on the characteristics of the reflecting surface. The technology provides an extremely high-resolution image of down to 3 m. This is crucial, as the ice structure may change greatly over just a few hundred meters. Faced with the situation of the Akademik Shokalskiy, the DLR ground station processed the satellite images in near real-time and transmitted them to the rescue centre in Australia just one hour after the acquisition of the Antarctic scenes. Scientists from the DLR Microwaves and Radar Institute (IMF) used TerraSAR–X to acquire images of the trapped research ship on 1 January 2014. Software at the DLR Research Center for Maritime Safety in Bremen was used to track the ships, by utilising the contrast and differing textures of the vessel and sea ice to detecting the vessels amongst the frozen masses.

• October 2013: To comply with increased requirements on data freshness, especially from the MERS (Maritime and Emergency Response Services) segments, Astrium Geo-Information Services / Infoterra GmbH has constantly been upgrading TerraSAR’s ground station network access. As a benefit, especially through improved polar station access and processing capabilities, NRT (Near-Real-Time) delivery requirements can be served since early 2012. ⁴⁶⁾In 2013, the product portfolio for TerraSAR-X was enhanced with two new operational modes for the user community: ^{47) 48) 49)} ST (Staring Spotlight) mode, available since October 15, 2013, with resolution: 0.25 m (azimuth) x 0.8 m to 1.77 m (range); scene size: 2.1 to 2.7 km (azimuth), 7.5 to 4.6 km (range); single polarization: (HH, VV); SCW (ScanSAR Wide) mode, available since July 14, 2013, with resolution: 40 m (azimuth) x 6 to 10 m (range); scene size: 200 km (azimuth x 194 to 266 km (range); single polarization (HH, VV, HV/VH). The new TerraSAR-X Wide ScanSAR mode (SCW) provides an overview of an area of up to 400,000 km² within a single acquisition - anywhere and independent of weather conditions. Wide ScanSAR data is thus ideally suited for monitoring ship traffic, detection of oil spills, and monitoring of maritime assets and sea ice, and contributing to the security, safety and efficiency of maritime activities around the globe.

- TerraSAR-X standard HR product uses the High-Resolution Spotlight mode with 300 MHz chirp bandwidth and offers an azimuth resolution of 1.1 m at 5 km azimuth scene extension with variable ground range resolution as a function of incidence angle at 10 km ground range scene extension. A so-called sliding Spotlight mode is used to generate this product. This results in a fairly good azimuth scene extension and equally distributed SNR across the image while grating lobes are reduced to a minimum to achieve the best possible ambiguity performance. The system is, however, capable of an improved azimuth resolution by applying the so-called ST (Staring Spotlight) mode operationally available as of fall 2013. This provides the best possible azimuth resolution (0.2 m, 1 look) using a much greater azimuth steering angle range from ±2.2º compared to the sliding Spotlight mode. It has been shown that the azimuth ambiguities that occur because of wide azimuth beam steering can be controlled by proper timing commanding. the azimuth scene extension increases with incidence angle, in contrast to the sliding Spotlight mode with constant azimuth scene extension. Different from Spotlight operations the Stripmap modes apply a SAR antenna beam that is always orthogonal to the flight direction.

• August 30, 2013: With a spacecraft design life of 5 years, TerraSAR-X should have been out of service for over a year and a half (launch on June 15, 2007). However, engineers at DLR switched the satellite to yet another mode: TerraSAR-X could now record image strips over 200 km wide (in ScanSAR Wide mode, also referred to as SCW). The satellite does so by sweeping this large area in multiple stages, very quickly pivoting the radar beam numerous times across the direction of flight.

- TerraSAR-X had already delivered more than 120,000 images since being launched. However, the image strips from the TerraSAR-X satellite have been limited to a width of 100 km so far. For the first time, DLR is able to acquire an image of the entire German Bight from east to west, at a single point in time and in high resolution. The wide-swath radar imagery is providing the oceanographer with a great deal of information on the tidal flat and associated inlets between individual islands and the coast, as well as on the high water level in the Elbe estuary and near the island of Sylt. The operational condition of the TerraSAR-X spacecraft and its payload is still very good and the fuel reserves should enable the mission to continue operating until at least 2015

• June 2013: Following severe flooding in northern India and Nepal, the Indian government activated the 'International Charter Space and Major Disasters on 19 June 2013. DLR tasked its radar satellite TerraSAR-X with acquiring images of the affected areas and made these available to the Indian civil protection authorities. ⁵²⁾In India, the situation was far worse than initially thought. The effects are especially bad in the mountainous state of Uttarakhand, where the Ganges River and its tributaries have flooded. TerraSAR-X has imaged this region over the last few days.

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