Watching the despots

Despots don’t like being watched. In September 2007 the Burmese ruling military junta commenced a brutal crackdown on their citizens in response to huge street protests. They tried to prevent the world from knowing what was happening by cutting telephone lines, shutting down websites and closing internet cafes. However, they failed to keep their activities secret since they were being watched all the time by high-resolution Earth-observation satellites. In fact, satellites had been monitoring human rights abuses in Burma for a number of years. Images had been produced showing clear indications of destroyed or damaged villages, growing refugee camps, the build-up of military bases and the appearance of new villages near those military bases suggesting forced relocations.

This was the work of The American Association for the Advancement of Science (AAAS) who set up the Geospatial Technologies and Human Rights Project in December 2005. The purpose was to assess how Earth-observation satellites could be used to detect and monitor human rights abuses. They have now carried out a number of studies. In addition to their work in Burma, images have been collected of the damage done to the infrastructure of Southern Lebanon by the Israeli military. Studies have also been carried out of the destruction of homes and businesses of four communities in Zimbabwe’s Operation Murambatsvina. And attacks by the Sudanese government-backed militias against civilian communities in Darfur, Sudan and Chad have also been documented.

The first artificial satellite was Sputnik 1, launched by the Soviet Union in 1957. Now, just over 50 years later, there are around 3000 functioning satellites orbiting the Earth. These satellites study the weather, transfer telephone calls, relay television programmes, aid navigation, carry out military tasks, and now, monitor human rights abuses.

Observing the Earth was an early priority for artificial satellites. The first satellite photographs of Earth were made in 1959 by the US satellite Explorer, although only rather poor quality low-resolution pictures were obtained. The technical progress which has been made since those early days is impressive. Quickbird, an imaging satellite owned by DigitalGlobe, is one of the satellites used by the AAAS. It weighs about one tonne, travels at 7.1 km/sec at 450 km above the Earth. It orbits the Earth every 93.4 minutes and produces images with a resolution of 0.61 metre and snapshots 16.5×16.5 km or strips 16.5km x 115 km. Each area of the Earth is revisited every 2 to 3 days depending on the latitude.

The image sensors record green, red, blue and near infra-red wavelengths which can be used separately or combined to detect chosen features. For example, the red, green and blue channels can be combined to produce true colour pictures. The infrared can be combined with other frequencies to highlight vegetation which can be useful in humanitarian work, where overgrown agricultural areas may indicate mass displacement of people. Quickbird produces sharp focus views of buildings, building-destruction and soil disruption that might mark mass graves. It can detect small houses, fencing, footpaths, and vehicles. It can distinguish between cars and trucks, and between military and civilian vehicles.

Although Earth-observation satellites have been around for a long time their use for humanitarian purposes has only become possible in recent years. The high-resolution images produced by military satellites have never been available to the general public and images from privately-owned satellites are traditionally expensive. But now, with more satellites collecting more images, resolution is increasing and costs are coming down. Some satellite companies, including DigitalGlobe, now provide images at discounted prices for humanitarian work.

There are, of course, limitations on what can be achieved with Earth-observation satellites. For example, Burma is largely covered in forests and there is frequent cloud cover, especially during the monsoon season, which restricts observations. The killing or imprisoning of small numbers of people cannot be identified from satellite images. In many parts of the world there are no archived images so that before-and-after pairs cannot be produced, although, as time passes, more and more of the Earth’s surface is being recorded.

A good example of the value of this work is the study showing unequivocally that the Zimbabwe government had destroyed an entire settlement and relocated the people who lived there. The AAAS have before-and-after image sets of the settlement called Porta Farm just outside the capital Harare. The first is an archived image which appears to show nearly a thousand homes. It is possible to manually count the number of structures and it is believed that up to 10,000 people were originally living there. In the second image, collected in April 2006, the settlement has gone. The operation was called Operation Murambatsvina which translates as Operation Restore Order or Drive Out Trash.

The satellite evidence was used by Amnesty International and Zimbabwe lawyers in the preparation of a report to publicise human rights violations by the Zimbabwe government. The images will also be used in a legal action in Zimbabwe by those who lost their homes. The Zimbabwe government claimed the action was designed to clear illegal slums and black market areas but in reality, of course, it was designed to retaliate against those who opposed the Mugabe regime.

In future will it be possible to use Earth-observation satellites to predict the onset of human rights abuses? Some scientists think so. Fires may show that a campaign of repression is beginning and drought or other disruptions may be precursors to human rights abuses. Scientists are studying past conflicts and collecting information such as general disruption, economic data, eyewitness accounts and satellite images to find common patterns which precede repressive campaigns. Mathematical modelling of data from potential trouble spots may then become possible and governments might be persuaded to intervene at an early stage.

Alan I. Leshner, chief executive officer of AAAS, is optimistic. “We believe this technology will become a critical tool for human rights organisations worldwide. The satellite images show the technology has enormous potential for helping to prove broad human rights violations. And perhaps someday in the future, the technology will make it possible to intervene earlier in a human rights crisis, before it’s too late.”

About the author

Chris Holt is a physicist with a BSc from Sussex University and a PhD from Nottingham University. For many years he carried out blue sky research at Unilever’s Corporate Research Laboratory in Bedfordshire. He has presented papers at a number of international symposia and published many academic papers. He is the holder of seven patents. He now works as a freelance science journalist.