By Helen Briggs BBC News Online science reporter

Thanks to images taken by a US space agency (Nasa) satellite, authorities were at least able to monitor the situation and make plans to evacuate residents.

AlSat-1, the first satellite launched for Algeria, under manufacture at the Surrey Space Centre In pictures

Hi-tech satellite imagery is increasingly being used by international agencies and governments to help deliver aid when disaster strikes.

But, while there is no shortage of earth-observing satellites orbiting the globe, they are not always in the right place at the right time to take pictures.

This is about to change. Next month, three satellites belonging to Nigeria, Turkey and the UK, will be launched from the Plesetsk Cosmodrome in Russia.

The first satellite, from Algeria, was launched last November and is now operational.

Together, they will form a constellation of micro satellites dedicated to disaster monitoring that will cover the whole world every day for the first time.

Smaller, cheaper

The satellites have been built by a spin-off company from the University of Surrey in Guildford, southern England.

The firm, Surrey Satellite Technology Ltd, is leading the disaster monitoring constellation, a collaboration of organisations in seven countries: Algeria, China, Nigeria, Thailand, Turkey, Vietnam and the UK.

What is different about these satellites is that they are smaller and cheaper than most; this makes them more accessible to countries that don't have sophisticated space programmes.

"Space has been the reserve of the large economies traditionally for the last 20 years," says senior marketing manager Paul Stephens.

"But we have been working to build small satellites at very low cost at Surrey and these have been based on using commercial, off-the-shelf components that are used in every day computers and cars and so on.

"By cutting the cost by perhaps a factor of ten it means that many more countries can afford to have presence in space that enables their own scientists and people to use that resource in the country."

Knowledge transfer

Engineers from 12 emerging space nations, including Algeria, Nigeria and Turkey, have spent months at the green lake-side campus where Surrey Satellite Technology Ltd is based.

Alongside the company's staff, they learn the technology to build and operate satellites when they return home.

ALSAT-1 was launched in November 2002

Once the satellites are in operation late this year, each nation will have its own resource for geographical mapping, while contributing 5% of satellite time free of charge for international disaster relief through the charity Reuters AlertNet.

"If a disaster strikes, people need information very quickly and the existing satellite infra-structure has difficulty responding within 24 hours," says Ian Downey, head of applications and market development at the British National Space Centre in London.

He says Britain's contribution to the programme, the satellite UK-DMC, is primarily to complete the constellation for disaster relief work.

"The UK satellite will help to provide 24-hour coverage of the globe for disaster relief and natural resource monitoring," he says.

Information from the constellation of satellites should also prove invaluable to aid workers in the field.

Using hand-held devices, that will be able to get up-to-date images and maps wherever they are in the world.