The Xindi test strike gives Earth a warning

The Xindi test a smaller version of their Earth-destroying weapon against its intended target. The strike cuts a huge scar into Earth and reveals the danger before the main weapon is ready. Earth sends a ship into the Expanse to investigate its origin. The warning also gives the defenders an opportunity to examine the attack, reverse-engineer its technology, and prepare defenses. A ring of space fortresses is suggested as an expected response, although the story does not show such preparations on the scale expected here. The Sphere Builders exploit divisions among the Xindi, prompting a comparison with colonial control through rival groups.