1. The Dart and Orion missions
The year opened with a bang. Or rather, it didn’t. The successful film Don’t Look Up, in which a comet is found to be on a collision course with Earth, had been released just before Christmas 2021. In the bleak days of post-festive gloom, the news media were on an adrenaline high, chasing any and every story about potential asteroid collisions to cheer us all up. Five asteroids were to pass close to the Earth in January alone! Happily for the health and wellbeing of humanity, none was predicted to come within a whisker of hitting the planet. Nonetheless, the possibility of an asteroid colliding with Earth is a reality – the globe is covered in craters from previous impacts, and it is well known that 65m years ago, dinosaurs became extinct following the impact of an asteroid about 10km across. Can anything be done about saving us from this existential extraterrestrial threat? Fortunately, the international space community has taken the first steps towards reducing the risk of an asteroid catching us unawares. The joint Nasa- Esa mission Dart (Double Asteroid Re-Direction Test) was an ambitious attempt to alter the trajectory of a small asteroid (Dimorphos) as it orbited a slightly larger asteroid (Didymos), by sending a spacecraft to crash into it. In October, we learned that the mission had been even more successful than anticipated, and that the orbit of Dimorphos had changed – showing that we could, if given sufficient time, alter the path of an asteroid if it were on a collision course with Earth.
