THE circle of the London Eye, a big ferris wheel, is just visible. The curving glass roof of Waterloo Station looks like a faint white blur. Three bridges over the River Thames can be distinguished, and scattered dots on the river indicate boats. This is the view of London's South Bank, seen from overhead through the eyes of a satellite with a spatial resolution of ten metres (the smallest feature it can distinguish, in other words, is ten metres across). Next to this image on the computer screen, however, is another view of the same scene, with a spatial resolution of just under a metre. The difference between the two pictures is stunning. Individual struts can be picked out on the London Eye, roof panels can be distinguished on Waterloo Station, individual boats can be seen on the river and trains on the railway; it is even possible to make out their shadows. Streets, trees and buildings are all sharply defined.

Ever since the 1960s, people in military intelligence have known the value of “one-metre” imagery. According to John Pike, an expert on satellite imaging at the Federation of American Scientists in Washington, DC, one metre is the “sweet spot” that makes it possible to tell cars from lorries, to recognise types of fighter aircraft, to count vehicles in convoys, to distinguish different kinds of tank, and to identify buildings for target selection.

For decades, images of this quality were available only to superpowers and their closest allies, because only they could manage the feat of launching satellites or spyplanes capable of taking one-metre pictures. Not any more. Ikonos, the satellite that took the one-metre view of London, is only the first of several commercial high-resolution satellites that are being launched in the coming months. Such satellites will make what was previously military-grade imagery available to all. The firms responsible for launching them believe that one-metre imagery will create a host of new business opportunities, and open up a lucrative new market worth billions of dollars.

Not everyone shares this optimism. Some analysts believe the market for high-resolution satellite imagery has been overstated. Others think the companies' profits are more likely to come from selling images for military purposes to countries that cannot afford their own spy satellites.

Imaging satellites are merely the latest example of a technology that was originally developed for military purposes going on to find commercial applications. Such “dual-use” technologies pose a huge problem for governments. A balance has always to be struck between maximising the commercial potential of a particular technology and minimising the risk that hostile powers will benefit from it.

On May 1st, the Americans lifted their restrictions on another dual-use satellite technology when they said they would stop degrading signals transmitted by global positioning system (GPS) satellites. This will allow civilian users of GPS devices to determine their position with the same accuracy as military users. The commercial benefit of allowing unfettered access to GPS was deemed to outweigh the military drawbacks.

Knowing your exact position, wherever you are in the world, is one thing—but the implications of being able to spy on anybody, wherever they are in the world, will be far greater. Will the advent of high-resolution commercial-imaging satellites have a dangerous and destabilising effect? Or will it, as some hope, usher in a new era of glorious transparency?

The eyes have it

Satellite images have been available commercially for years. The first civilian remote-sensing satellite, Landsat 1, was launched by America in 1972. With a spatial resolution of 80 metres, it could show forests but not trees, towns but not buildings. Although such images have scientific, environmental and educational applications, they have limited commercial value. (More detailed images have since become available from such sources as the French SPOT satellites, which have a resolution of ten metres.) Similarly, high-resolution imagery, in limited form, is not new either. Aerial photography can already produce images with spatial resolutions of one metre or better. But high-resolution satellite imagery offers the best of both worlds: levels of detail comparable to aerial photography, with the global coverage and timeliness that only satellites can provide.

Admittedly, taking pictures from space and beaming them back to earth is a complex business. Ikonos, which is operated by an American firm called Space Imaging, orbits the earth every 98 minutes at an altitude of 680 km (425 miles), selectively snapping away with its digital camera as it goes. Meanwhile the planet revolves beneath it, so that the satellite passes over a given spot every three days. If a particular spot needs to be captured more frequently than this, the satellite can be pointed, allowing places not directly underneath it to be photographed, though at the cost of a slight reduction in image resolution. Captured images are transmitted to earth via a network of ground stations, and then sent to Space Imaging's headquarters in Denver, Colorado. Here the images are processed and corrected to ensure that they are geometrically accurate (a process known as ortho-rectification) and are then sent to the customer in digital form.

Since it is essentially a flying digital camera, Ikonos cannot take pictures at night, or see through clouds. But its sensitivity enables it to capture exquisite detail, even in shadows. As well as its black-and-white sensor, which has a spatial resolution of 0.82 metres, Ikonos also has a multispectral (ie, colour) sensor, with a resolution of four metres.

Space Imaging, whose backers include Lockheed-Martin, Raytheon, Mitsubishi and Hyundai, is not the only game in town, though it was the first to get a commercial one-metre “bird” into orbit. Early next year Orbimage, of Dulles, Virginia, plans to launch its own one-metre satellite, OrbView-3. Like Ikonos, it will be able to capture one-metre black-and-white and four-metre colour images. OrbView-4, which is due for launch in 2001, will offer “hyperspectral” capabilities that can distinguish between different materials. This has peaceful uses, such as spotting oil-rich mineral deposits, and military ones, such as spotting camouflaged vehicles in dense foliage.

Also planning to launch one-metre satellites are EarthWatch, another American firm, and West Indian Space, a joint venture between two Israeli technology firms and an American software company that is registered in the Cayman Islands. EarthWatch's satellites, called QuickBird 1 and 2, will offer similar imaging capabilities to those of Ikonos and OrbView-3. West Indian Space plans a more adventurous scheme, involving two satellites with 1.8-metre resolution and six with 0.82-metre resolution, the first of which will be launched this summer.

If you build it, they will come

Building and launching satellites is an expensive business. So far, Space Imaging's backers have invested a total of $750m in the venture. Orbimage is spending $250m on its two satellites. EarthWatch has raised $186m to pay for its QuickBirds. And West Indian Space's first three satellites are expected to cost a total of $300m. At the moment, the global market for satellite images is worth a mere $154m, compared with $2.4 billion for aerial photography, according to Ron Stearns, an analyst with Frost & Sullivan. But the satellite firms are betting that one-metre imagery will open up a vast new market.

For example, utility companies, suggests Mark Brender of Space Imaging, can use one-metre imagery to plan the routes of pipelines through desolate regions for which no detailed maps exist. Detailed images could also help government bodies with zoning, planning and the monitoring of urban sprawl. Insurance companies that provide coverage against forest fires can see if home owners have cleared the underbrush on their property, and if not, charge higher premiums. Estate agents will be able to show potential clients exactly how far that Hamptons bolt-hole is from the golf-course; travel agents will be able to show customers how far a hotel is from the beach. According to Gilbert Rye of Orbimage, multispectral and hyperspectral imaging can also allow farmers to monitor crop health, allow fishermen to spot shoals of fish, and help prospectors to find oil, gas and minerals.

Consumers will no doubt want to buy images of their own homes, or of well-known places such as the Giza plateau or downtown Manhattan. Even three-dimensional images and relief maps are possible, by getting a satellite to take two images a few seconds apart as it passes over a particular spot and then combining them using special software. Space Imaging is putting together 3-D models of cities that users can “fly” around on their PCs.

Yet estimates of the size of the market for satellite imagery vary widely, mainly because analysts are divided over the extent to which satellites will cannibalise the far more lucrative market for aerial photography. Tom Watts of Merrill Lynch believes that global sales of satellite images will be worth $2.5 billion by 2005. Mr Stearns, on the other hand, puts the figure at a mere $420m.

Indeed, much as they talk up the commercial potential for one-metre images, the satellite firms know that governments are likely to be the keenest customers, at least in the short term. In America, the Defence Department has said it plans to increase spending on commercial services, including satellite imagery, by $1 billion over the next five years; several other national security agencies have made agreements to buy commercial one-metre images. West Indian Space expects most of its business to come, at least at first, from the Israeli government. From a military point of view, its six one-metre satellites will be far more useful than a single satellite, because they allow the same point to be imaged every few hours, rather than every few days. Other much smaller countries that cannot afford their own spy satellites are also expected to be keen customers. Governments around the world, says Mr Pike, are “drooling for this stuff”. Hardly surprisingly, the question of who should be able to buy what is hotly contested.

No peeking

The availability of one-metre images clearly has political and military implications. There is evidence that Iraq used SPOT images to plan attacks during the Iran-Iraq war. Up-to-the-minute satellite images, had they been available to the Iraqi leadership, could have revealed the surprise “left hook” manoeuvre used by allied forces in 1991 to liberate Kuwait. To prevent images falling into what it regards as undesirable hands, the American government has imposed restrictions on those firms that operate high-resolution satellites.

For a start, the usual rules against doing business with rogue states and known terrorists apply. These rules apply to the sale of satellite images just as to everything else, from fridges to rocket-launchers. Space Imaging and Orbimage say they carry out routine background and credit checks before selling images. But, as Mr Rye acknowledges, no system is fail-safe.

In addition, and more controversially, an American presidential directive signed in 1994 allows the imposition of short-term “shutter control” to restrict the availability of images (such as one-metre images) that might compromise national security. In 1997, a law was passed to forbid American companies from taking or selling satellite images of Israel, “unless such imagery is no more detailed or precise than satellite imagery that is routinely available from commercial sources.” At the moment, the highest-resolution images available on the market are Russian two-metre images, so this precludes the capture and sale of one-metre images of Israel. Space Imaging, Orbimage and EarthWatch are all bound by this legislation, and West Indian Space, being Israeli-backed, will follow a similar policy. Orbimage has also agreed to restrictions on the sale of hyperspectral images from OrbView-4.

But it is the legislation on temporary shutter control, which has yet to be invoked, that is proving most controversial. Last year, during the conflict in Kosovo, it looked as though restrictions would be imposed for the first time, as Space Imaging prepared to launch its first Ikonos satellite on April 27th. The satellite was, however, lost in a launch mishap, so the workability of the legislation remains untested.

There are several reasons to believe that shutter control will prove impractical. Mr Pike points out that defining the area of shutter control poses one big dilemma. Make the area too small, and you reveal the location of whatever it is you are trying to protect (a forward refuelling base for Apache helicopters, for example). Make the area too large, on the other hand—the Kosovo conflict might have put the whole of south-eastern Europe off-limits—and it will prevent legitimate commercial imaging. It would also look rather odd to allow images of a friendly airbase to be taken by television cameras on the ground, but not from space.

Then there is the First Amendment. Mr Pike says that several news organisations, which have already made use of lower-resolution satellite imagery, plan to challenge the shutter-control legislation in the courts as soon as it is invoked, on the grounds that it contravenes freedom of speech. The government may have to be sparing in its application of shutter control to avoid losing and having its legislation overturned.

In any case, says Ann Florini of the Carnegie Endowment for International Peace in Washington, DC, who has just published a report on satellite policy (available at, shutter control will eventually fail because it is based on a short-term view. For the next few years, only American and Israeli companies will be producing commercial one-metre imagery; but Russia, India and France will soon enter the field, and China, South Korea, Japan and Pakistan plan to launch high-resolution satellites too. Before long it will be impossible to stop anybody from obtaining an image of any part of the world, no matter how sensitive, from one source or another. “To base policy on a monopoly you know you are going to lose shortly is short-sighted,” says Ms Florini.

A transparent world

In any case the ubiquitous availability of one-metre imagery, unfettered by shutter controls, might not be as damaging as the Pentagon fears. Spy satellites are generally thought to have had a stabilising effect during the cold war. It is true that satellite images revealed hundreds of previously unknown targets on either side, fuelling demand for additional weapons to aim at them; but they also revealed the non-existence of the “missile gap”. Satellite imagery is also now a key element in the verification of arms-control agreements. Overall, the fact that both sides could see what the other was up to did more to relax tensions than to heighten them.

Ms Florini believes that the new transparency and accountability made possible by commercial high-resolution satellites will also do more good than harm. Countries in regions of high tension, she suggests, will be able to learn whether potentially hostile neighbours are mobilising for attack. Some attackers may even be deterred by the likelihood of detection.

In addition, the availability of such images to non-governmental organisations is likely to have a profound influence on policymaking. Members of the public will be able to see for themselves what is going on, rather than relying on what their governments tell them. At the Federation of American Scientists, Mr Pike runs a programme called “Public Eye” to “level the playing-field between the government and the electorate”. “Public Eye” has already bought several one-metre Ikonos images of North Korean and Pakistani weapons sites, and released them to the press with great fanfare.

The point, says Mr Pike, is that previously “the spooks knew about this, but the taxpayers did not”. He says the images reveal that North Korea's weapons programme is smaller than expected, and Pakistan's bigger. And in April Mr Pike obtained the first one-metre images of Groom Lake, better known as Area 51, the most secret military complex in America, where—to the disappointment of conspiracy theorists—there were no flying saucers to be seen. (Space Imaging sells the Area 51 pictures, along with images of Saddam Hussein's palace in Baghdad, several major city centres, and other sites of interest, on its website.

Images of North Korean or Pakistani sites would not of course be new to those in American military intelligence who, with a 30-year head start over commercial operators, have satellites capable of producing even more detailed images (with a resolution of ten centimetres or so). Governments around the world have long lived with the fact that their every move was being observed by the superpowers. What is new is that their own civilians, and those of other countries, will now be able to see what they are up to as well. India, for example, is considering making it illegal for anyone but the government to buy high-resolution images.

As well as trying to restrict the availability of satellite images, governments will respond to being spied on in two ways, says Ms Florini. They may consider the deployment of anti-satellite weapons to shoot down or blind prying eyes, if necessary. But it is more likely that they will learn to live with the satellites, and concentrate instead on new concealment techniques and decoys to confuse overhead observers, such as burying facilities underground and deploying fake tanks and ships, as the Soviet Union once did.

The lesson of history

In the past, other new communications technologies have also forced changes in the ways that wars are fought. Before the introduction of the electric telegraph in the 1840s, for example, it was common practice for the details of British ships departing for foreign conflicts to be published in full in the Times. But by the time of the Crimean War in 1854, the international telegraph network meant that such details could be immediately telegraphed to the enemy in St Petersburg, giving several weeks' warning of the arrival of British forces. General Simpson, the British commander-in-chief, complained that “our spies give us all manner of reports, while the enemy never spends a farthing for information. He gets it all for five pence from a London paper.” The practice was discontinued soon afterwards.

Similarly, in recent years it has become commonplace for television news reporters to make live reports from behind the front line. But instead of worrying about giving information away to the enemy, it is now generally assumed that Saddam Hussein and Slobodan Milosevic will be tuning in; broadcasting has become a powerful propaganda tool. Now that the implications of satellite-TV technology are understood, war is simply waged in a slightly different way.

High-resolution commercial imaging satellites look set to change the rules of war once again. Whether they will immediately prove to be profitable or peace-making remains to be seen, but in the long run the ubiquitous availability of satellite images is inevitable, and is likely to have positive effects. Try as they may to restrict or control these eyes in the sky, governments will simply have to get used to them.