Images have been securely transmitted by satellite using Quantum Key Distribution (QKD) between ground stations in China and South Africa, a record-breaking distance of 12,900 kilometers (8,000 miles). More important than the distance is the drastic reduction in weight, and therefore ultimately of cost, in the transmission and reception technology. ADVERTISEMENT The weirdness of quantum mechanics can be harnessed to allow the secure transmission of data, at least in theory. Doing it at scale and over large distances has proven much slower than boosters anticipated. Nevertheless, progress has been made, marked now by the first quantum satellite communication link to...