It’s another big news day for defence tech startups in Europe. Stark — the company building air and surface attack drones and the systems that are used to control and coordinate them — has just confirmed that it has closed a funding round of €500 million ($570 million) from investors that include Sequoia Capital, Founders Fund, the NATO Innovation Fund, Project A, Air Street Capital, 201 Ventures, Advent and Döpfner Capital.