Forerunner Ship

Summary
There is a Forerunner ship used to power High Charity. When the Flood attack the city, the Prophet of Truth uncouples the ship from High Charity's power grid, and uses it to travel to Earth. The Forerunner ship travels vertically, like a rocket. It is also capable of slipstream travel.

Images
http://img146.echo.cx/img146/4969/sightsthumb9mq.jpg