Watching your satellite being launched has to be nerve-wracking enough, but when the spacecraft is intended to be one of a pair it must be doubly so. Well, Germany's TanDEM-X got off to a good start on June 21 with a successful launch from Baikonur on a Russian Dnepr rocket.
TanDEM-X - which stands for TerraSAR-X Add-on for Digital Elevation Measurement - is intended to rendezvous and fly in formation with Germany's TerraSAR-X radar satellite, which was launched in 2007. Together the two spacecraft will survey the Earth's surface to produce a high-resolution 3D elevation model.
TerraSAR-X and TanDEM-X are to orbit just a few hundred meters apart at an altitude of 514km and together will constitute the first configurable synthetic-aperture radar (SAR) interferometer. The two satellites will image the same geographic area from different viewpoints and distances, producing an interferogram from which the 3D elevation data will be derived.
TanDEM-X is a public-private partnership between German aerospace center DLR and the satellite's manufacturer Astrium. with Astrium subsidiary Infoterra responsible for commercial marketing of the data. DLR is providing 125 million euros of German government funding and Astrium is contributing 40 million euros.
Mapping the Earth's 150 million square kilometers of land surface is expected to take three years, so the TanDEM-X/TerraSAR-X elevation model is scheduled to become available in 2013. Data processing will be done by DLR, while Infoterra will adapt the resulting elevation model to the needs of commercial users.