German Aerospace Center DLR is taking over the rotating chairmanship of the International Charter on Space and Major Disasters, a multinational network of space agencies that for more than a decade has provided bureaucracy-free satellite assistance in the form of imagery to countries in the grip of natural or manmade disasters.

Created in July 1999 by French space agency CNES and the European Space Agency (ESA), the charter's core membership comprises 15 national space organizations, with Ukraine expected to join soon. In addition, authorized users in 41 countries can activate the charter on their own, while more than 90 nations participate through agreements with authorized users, via the U.N., or through regional emergency response networks, including the 32-nation Sentinel Asia.

Using satellite imagery, relief workers are able to identify roads or bridges that remain passable after an earthquake or a flood, as well as which buildings or towns are damaged.

To date, more than 110 countries have used the charter, which has been activated 369 times since the network was formed over a decade ago. Last year, it was called on 40 times in response to major natural disasters. In addition to Hurricane Sandy in the Caribbean and along the U.S. East Coast, these included a typhoon in the Philippines in early December that killed 1,900 people, floods in Pakistan in September that left 500 dead and an earthquake in Iran in which 300 lives were lost.

To trigger the service, authorized users request activation of the charter, and within 3 hr. a satellite is tasked with collecting imagery. Over the next 24-48 hr., satellite images are processed before being transmitted hours later to the users.

“Actually receiving the image is one of the longest and most unpredictable steps, because while we're in a situation now where we have a lot of satellite resources, we can have situations, for example, involving poor weather, so optical imagery isn't so useful,” says Steven Hosford, International Charter program manager for CNES. “Once we get the image, we extract some data and make a map product—this is a step not in the charter but which can take six to eight hours.”

The charter relies on nearly 20 optical and radar-imaging satellites owned by governments or companies in Argentina, Brazil, Canada, China, France, Germany, Japan, India, Russia, South Korea, the U.K., the U.S. and Taiwan.

DLR provides Earth-observation data from two German radar satellites, TerraSAR-X and TanDEM-X, that can acquire very detailed images regardless of cloud cover or daylight.

“Radar images are ideally suited to mapping flood disasters, as they clearly distinguish between expanses of water and land,” says geographer and charter secretary, Jens Danzeglocke. In some cases, DLR also assists with optical data from the RapidEye satellites, in the event of forest fires, for example, or after particularly extensive incidents, such as the March 2011 earthquake and tsunami in Japan.

Since the charter was formed, founding member CNES has been among the most active members in terms of responding to disaster relief and security needs. The agency is involved in more than 80% of charter activations at a rate of 30-40 times per year via its SPOT 5 Earth-observation satellite, which provides the bulk of French imagery; it has delivered 100 pictures a year since 2000.

For now, SPOT 5 imagery is complemented by data from the U.S. National Oceanic and Atmospheric Administration and the U.S. Geological Survey's (USGS) Landsat satellites as well as high-resolution optical satellite imagery provided by U.S. commercial fleet operator DigitalGlobe to the USGS through the National Geospatial Intelligence Agency.

With SPOT 5's retirement expected in 2015 and no French-government-owned successor to follow, the organization will use imagery from the European Union's Sentinel 2 Earth-observation satellites—slated to launch in 2014 but likely to be delayed—and France's new twin sub-meter-resolution Pleiades optical-imaging satellites launched in 2011 and 2012.