Dropball is a solo sport played by launching a ball from orbit towards the surface of a planet while following a set of rules. The sport can be regarded as a ritualized version of military skill competitions. Dropball is extremely popular in the system of Nadia, but has a wider following thanks to sanctioned Known Net recordings. A regulation dropball is 1 meter in diameter and composed of pure iron (99.9999%). Traditionally the launch site for the dropball has been Level 5 dock of the The Chiliagon Sport Center station, operating in the vicinity of the Vera-Lyuba L1 point. The dropball is released on a vector, undergoes atmospheric entry, heats up during aerobraking, and comes to rest with rapid lithobraking.
Scoring is based on the measured distance from the impact center of the ball to the predetermined target. The sport can be played with or without augmentation; however the later uses a modified scoring system to account for the enhanced ability. Dropball bombardments can take place throughout the year; there is an uptick in activity following the week long tournament of the Nadian Model Cityscape Creation Society.