A satellite that can provide 24/7 surveillance of a third of the Earth’s surface relies on a rare mineral whose global supply is dominated by China, a new study has disclosed.It orbits 36,000km (22,000 miles) above the Earth and is able to stay in what is known as a geosynchronous orbit, which keeps it fixed over the same spot.This allows it to monitor both large areas of the planet and moving targets – something the United States has spent decades trying to achieve without success.China has near-total dominance of the global supply of GaN – a key component in active electronically scanned array radars, electronic warfare systems and next-generation defence platforms – and has restricted gallium exports since the satellite launched in August 2023.03:36China restricts critical metal exports following Western semiconductor curbs in latest trade warThe metal is mainly extracted as a by-product of alumina production rather than mined independently and China, the world’s largest aluminium producer, accounts for more than 95 per cent of global primary gallium production.