An English satellite developer plans to launch a constellation of five satellites in early 2002 devoted to monitoring natural and human-made disasters from orbit.

Surrey Small Satellite Technology (SSTL) hopes to use the new network to facilitate management and relief efforts in crisis situations ranging from civil strife and industrial accidents to droughts, earthquakes, fires and landslides. Unlike multipurpose Earth-observing satellites that have monitored mishaps in the past, SSTL's satellite fleet will be solely dedicated to disaster observation.

The Disaster Monitoring Constellation will be able to monitor any point on Earth at least once a day.

SSTL will build the system as a commercial enterprise, where different participants will share the expense of deploying and maintaining the network. The company estimates the cost of the entire system at $40 million.

So far, the British government has agreed to fund one spacecraft, and recently Algeria bought another, said Audrey Nice, SSTL spokesperson.

"We are talking to Nigeria, Thailand and China," Nice said.

Along with the satellites, SSTL promised to offer users access to ground-control stations and a centralized mission planning system. The company expects all participants the share the resources of the system in cases of U.N.-declared disasters.

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Each of the five pyramid-shaped spacecraft weighs only about 40 pounds (80 kilograms) and SSTL plans to haul the entire constellation into orbit in a single launch. The company has yet to choose the rocket to do the job, and at present is considering Russian, Chinese, Indian and U.S. boosters.

"[Our] decision will be based on the best possible launch opportunity at the best possible price," Nice said.

The pyramid-shaped satellites will be launched in the same rocket.

The disaster-monitoring spacecraft will be inserted into circular 425-mile (686-kilometer) polar orbits. Thanks to Earth's rotation under the satellites, each spacecraft will revisit the same region over the planet at least once every 24 hours.

Each satellite's camera will have a resolution of 118 feet (36 meters); enough to conduct agricultural monitoring, hydrological mapping and assess damage known as hazard mapping. Such information will be used to monitor and possibly plan refugee movement, camp establishment and large-scale aid activities.

Each satellite will have a life expectancy of about five years. The architecture of the satellite allows the installation of additional cargo to the satellite's primary-imaging payload. Finally, the computers on the satellites could be reprogrammed in flight as more advanced software becomes available.

If additional customers express interest in the system after the original network has been deployed, a follow-on constellation will be developed and launched, SSTL representative said.