Aarti Holla-Maini of the UN’s Office for Outer Space Affairs is primed to spot a potential planetary strike – and a year ago, she thought the moment had come The UN official had trained for this moment. She had run drills and table-top exercises at her offices in Vienna, housed inside a grey and unassuming 1970s concrete tower complex next to the Danube River. Aarti Holla-Maini, a British lawyer with a background in the satellite business, needed to have at least played out the scenario step by