The archipelago that keeps growing

The runway is three kilometres long, paved, lit, and equipped with a control tower, reinforced hangars and missile shelters. It can handle H-6 bombers, J-11 fighters and long-range maritime patrol aircraft. Ten years ago, in its place, there was a submerged coral reef, barely a few dozen metres wide, home to fish and turtles. The transformation of that atoll into a permanent military base took place between 2014 and 2017, and it is one of seven comparable projects China has carried out in the Spratly Islands. A detailed record of that transformation exists at all only because satellites photographed it, week after week.

Figure 1 — One of the artificial islands in the Spratlys, seen by Planet SkySat. Visible are the roughly three-kilometre runway, the covered hangars, the military port to the west, and the cluster of administrative and residential buildings. The squared-off shape of the shoreline betrays its origin: the reef was dredged and filled with sand from the seabed to create a usable surface. None of the infrastructure visible here existed before 2014. Source: Planet Labs.

The South China Sea is one of the most contested stretches of water on the planet. China, Taiwan, Vietnam, the Philippines, Malaysia, Brunei and Indonesia all border it, and each of these countries claims more or less extensive portions of its waters, seabeds and islets. China, in particular, asserts a boundary — the so-called nine-dash line — that encloses roughly 90 percent of the basin and that, according to Beijing, has been part of national territory “since time immemorial.” In 2016 the Permanent Court of Arbitration in The Hague, ruling on a case brought by the Philippines, found that the line has no basis in the United Nations Convention on the Law of the Sea, and that China, by building its artificial islands, had violated its neighbours’ rights and permanently damaged the marine environment. Beijing rejected the ruling the same day, and its strategy has not changed since: keep turning reefs and coral shoals into garrisoned bases, knowing that every new square metre of dry land pushes the line of faits accomplis a little further forward.

From land, almost nothing is visible. The Spratly Islands lie hundreds of kilometres from any coastline, Chinese warships patrol the area, and access for journalists and independent researchers is effectively impossible. Everything we know about the progress of construction comes from a handful of sensors in orbit.

The natural instinct would be to look for them on Copernicus Browser, the public interface for the Sentinel satellites. Trying it, however, reveals something that is often assumed but isn’t true: over the Paracels, and over most of the South China Sea, the archive is nearly empty. Sentinel-2, an optical satellite, systematically images land and coastal strips but not the open sea, and oceanic atolls fall outside its acquisition tiles. Sentinel-1, a radar satellite, covers the area in Extra Wide swath mode, at a resolution of about 40 metres and on a monthly cadence — useful for spotting large ships, not for documenting the dredging of an atoll. Copernicus, in other words, follows a geographic hierarchy built around Europe, dry land and coastlines, and it leaves uncovered precisely the pieces of the world that matter most to geopolitical reporting.

Documenting what happens between the Spratlys and the Paracels therefore falls, in large part, to commercial operators. The backbone is American: SkySat, built by the California-based company Planet, is a constellation of twenty-one small optical satellites in sun-synchronous orbit at roughly 500 kilometres of altitude; it returns images at about 50 centimetres of resolution and can be tasked on demand against a single target. Pelican, also from Planet, is the new generation gradually replacing SkySat, with 30-centimetre resolution, near-real-time satellite-to-satellite links, and a planned constellation of around thirty units. Maxar and BlackSky, both American as well, round out the picture.

Figure 2 — An atoll in the Paracel Islands, occupied by China since 1974, photographed by Planet Pelican. Two runways are visible: the one at the top, on the main island, has been in service for years; the one at the bottom, on a sandy cay that until a few seasons ago sat at water level, is a recent construction. Together, the two runways double China’s operational capacity on the archipelago. Source: Planet Labs.

It would be wrong, however, to read this picture as complete dependence on the American market. European operators are also active in the South China Sea, on a regular basis: Airbus, with its Pléiades Neo family, offering resolution down to 30 centimetres, and Finland’s ICEYE, with a commercial SAR constellation that sees at night and through cloud cover at metre-scale resolution. These are sources that a number of think tanks, including the Asia Maritime Transparency Initiative at the Center for Strategic and International Studies, systematically incorporate into their analyses, alongside Maxar and Planet imagery.

There is then a third layer of observation, one concerned not with land but with the movement of ships. Beijing does not limit itself to building islands: it deploys a vast fleet of civilian fishing boats, the so-called maritime militia, to occupy, in practice, reefs that are still officially disputed and to obstruct Filipino and Vietnamese fishermen. When they want to disappear, they switch off the AIS transponder that is supposed to broadcast their position. Here too, in place of Sentinel-1, tracking in this part of the world is reconstructed by cross-referencing commercial AIS data (Spire, Kpler, MarineTraffic) with commercial SAR imagery, chiefly from Capella and ICEYE.

Figure 3 — Another atoll in the Paracel Islands, photographed by Planet SkySat. The right-hand part of the island hosts a small Chinese administrative outpost; the left-hand part, still being consolidated, shows a newly built quay and a sandy storage area. Between the two lobes of the atoll a protected inner harbour has been carved out, recognisable by the wake of a small vessel passing through. Even ten years ago the island on the right was inhabited, but the harbour structure and the strip of land on the left are entirely recent. Source: Planet Labs.

Europe is working on the next generation of Sentinel — Sentinel-1NG is expected to enter service by the end of the decade — and several member states are strengthening their own national capabilities, from France’s CSO to Germany’s SARah. These are largely institutional assets, not open like Copernicus, but they are pieces of the same evolving mosaic.

The moral of the artificial archipelago is twofold. The first: a chronicle of one of the past decade’s most fundamental geopolitical shifts exists at all because a market of commercial operators, mostly but not exclusively American, chose to sell imagery to journalists, researchers and think tanks. Without that market, the archipelago would already be a historical footnote. The second: the geography of what the European public can actually see reflects the priorities Copernicus was built around twenty years ago, and it is a geography that risks leaving uncovered precisely the scenarios that matter most for European security and public awareness. Deciding where to look is, in the end, already a decision in itself.