These images are processed into accurate elevation maps with a 12-metre resolution and a vertical accuracy better than two metres. The amount of data generated by the satellites will grow to 1.5 petabytes within three years, corresponding to a storage capacity of almost 200,000 DVDs. Like the TerraSAR-X mission, TanDEM-X is a project developed under a public-private partnership between the German Aerospace Center, DLR, and Astrium GmbH based in Friedrichshafen, Germany.