Disaster Monitoring Constellation
The Disaster Monitoring Constellation (DMC) consists of a number of remote sensing satellites constructed by Surrey Satellite Technology Ltd (SSTL) and operated for the Algerian, Nigerian, Turkish, British and Chinese governments by DMC International Imaging. The DMC provides emergency Earth imaging for disaster relief under the International Charter for Space and Major Disasters, which the DMC formally joined in November 2005. Other DMC Earth imagery is used for a variety of civil applications by a variety of governments. Spare available imaging capacity is sold under contract.
The DMC provides far larger areas of imagery than, but at comparable resolution to, established government imaging satellites such as Landsat. DMC imagery was deliberately designed to be comparable to Landsat imagery, in order to leverage the expertise and software of the large established remote sensing community used to working with Landsat images. Imagery can be provided far more rapidly from the DMC than from Landsat, thanks to having multiple similar satellites in orbit ready to cross over a point of interest, and the larger images produced. This brings the responsiveness that is needed for emergencies and for disaster support, with images provided across the Internet from the responsive satellite and a member country's ground station within a day or less of a request being made.
The individual DMC satellites are:
- AlSAT-1 (Algeria), launched November 2002, which completed its mission in August 2010.
- BilSAT (Turkey), launched September 2003, which completed its mission in August 2006 due to failed battery cells 
- NigeriaSAT-1 (Nigeria), launched September 2003, completed mission October 2012.
- UK-DMC (United Kingdom), launched September 2003, completed mission November 2011.
- Beijing-1 (China), launched October 2005.
- UK-DMC 2 (United Kingdom), launched July 2009.
- Deimos-1 (Spanish commercial), launched July 2009.
- NigeriaSAT-2 and NigeriaSAT-X (NX) launched 2011.
The sun-synchronous orbits of these satellites are coordinated so that the satellites follow each other around an orbital plane, ascending north over the Equator at 10:15 am local time (and 10:30 am local time for Beijing-1).
Some of these satellites also include other imaging payloads and experimental payloads: onboard hardware-based image compression (on BilSAT), a GPS reflectometry experiment and onboard Internet router (on the UK-DMC satellite). The DMC satellites are notable for communicating with their ground stations using the Internet Protocol for payload data transfer and command and control, so extending the Internet into space, and allowing experiments with the Interplanetary Internet to be carried out. Many of the technologies used in the design of the DMC satellites, including Internet Protocol use, were tested in space beforehand on SSTL's earlier UoSAT-12 satellite. 
- J Cooksley, A da Silva Curiel, P Stephens, L Boland, S Jason, W Sun, M Sweeting, "ALSAT-1 First Year In Orbit", 17th AIAA / USU Conference on Small Satellites, 2003
- Algeria’s first satellite mission completed, Robin Wolstenholme, SSTL space blog, 26 August 2010.
- BilSAT News, retrieved 23 July 2007.
- NigeriaSAT-1 reaches end of long life, SSTL space blog, 29 October 2012.
- UK-DMC-1 to take well-earned retirement, SSTL space blog, 25 November 2011.
- DMCii to launch new higher-resolution satellite imaging service, SSTL press release, 20 March 2007.
- Deimos and Surrey Satellite Technology Contract for Spanish Imaging Mission, SSTL press release, 10 October 2006.
- "SSTL launches two EO satellites for Nigeria". SSTL.
- Use of the Delay-Tolerant Networking Bundle Protocol from Space, L.Wood et al., Conference paper IAC-08-B2.3.10, 59th International Astronautical Congress, Glasgow, September 2008.
- UK-DMC satellite first to transfer sensor data from space using 'bundle' protocol, press release, Surrey Satellite Technology Ltd, 11 September 2008.
- K. Hogie, et al., Using standard Internet Protocols and applications in space, Computer Networks, special issue on Interplanetary Internet, vol. 47 no. 5, pp. 603-650, April 2005.
- K. Hogie, et al., Putting more Internet nodes in space, CSC World, Computer Sciences Corporation, pp. 21-23, April/June 2006.
- Surrey Satellite Technology Ltd
- International Charter for Space and Major Disasters
- DMC International Imaging
- Description of the Disaster Monitoring Constellation from the Computerworld Honors Awards
- Description of the Disaster Monitoring Constellation from the Earth Observation Portal