ESA to live tweet asteroid impact exercise For almost a decade, world asteroid experts have been meeting every two years at the Planetary Defense Conference and pretending an asteroid impact is imminent. Why? To prepare for the unlikely – but plausible – scenario in which this comes true. For the second time in the conference's history, this major international asteroid impact exercise will be covered live via ESA social media, primarily via the @esaoperations in Twitter, highlighting the actions that might be taken by scientists, space agencies and civil protection organisations. Planetary Defense Conference goes digital This year’s conference is hosted by the United Nations Office for Outer Space Affairs, UNOOSA, in cooperation with ESA and under the umbrella of the International Academy of Aeronautics (IAA). Many other space agencies and organisations are also involved, including NASA, the International Asteroid Warning Network (IAWN) and the Space Mission Planning Advisory Group (SMPAG), among others.