Asteroid impacts are crucial events for the evolution of Earth. Asteroids and comets may have transported some of the ingredients of life (water and organic molecules from the outer solar system to our planet. At the same time, there is strong evidence that impacts destroyed much of the life on earth multiple times. The last and most famous event is the impact of an order of 10 km sized object that led to the extinction of dinosaurs, 65 million years ago. Those big impacts are rare, however, much smaller events can create large damage. The estimated age of Meteor Crater in Arizona, an impact crater of approximately 1.2 km in diameter, is only 50000 years. Only a century ago, in the Tunguska event on 30 June 1908, a small asteroid exploded in the atmosphere above Siberia and destroyed more than 2000 km2 of Forest. And very recently, in 2013, the impact of an only ~20 m asteroid damaged a large number of buildings in the Russian town of Chelyabinsk, luckily killing nobody, but injuring more than 1500 people. The question is not if another asteroid will get on a collision trajectory, but when it will happen.
For the first time in history, humankind is becoming able to prevent a catastrophic asteroid impact. Search programs are nearly complete for km-sized near-earth asteroids, and are striving to reach completeness for 100m-sized objects in the next years. Deflection of hazardous asteroids is in reach with current technology. In the International AIDA cooperation, NASA’s DART mission is in development for launch in 2021 for a deflection demonstration of asteroid Didymos in 2022. ESA’s Hera spacecraft, currently under study, is expected to follow on to study the impact effect in 2026.
Abstracts are invited covering all aspects of planetary defense: Search programs for near-earth asteroids, dynamical and physical characterization of potentially hazardous objects, theoretical studies of potential deflection methods, and all components of deflection missions.