Asteroid

The Asteroid addon adds -you guessed it- asteroids to the Echo Cluster. Asteroids appear as UFOs out of nowhere, and fly through the cluster on their own. But the best part is that they can be towed by ships (not by one-engined ships though) to anywhere you want them.

Asteroids can only be seen from a configurable distance, so don't be surprised if you don't see any of them for quite some time. You can intercept asteroids using the IA# friendly code (where # is the number of the asteroid) and then tow them using a friendly code of TA# (yes, # is still the number of the asteroid) while you're also performing other missions like minesweeping, sensorsweeping or cloaking.

Towing an asteroid is quite a nice thing to do in itself, because as long as you're towing that asteroid you will not burn any fuel. This is a nice way to move a lot of clans through your territory, or to have a warship travel a long way into enemy space. But of course this is not the main purpose of the asteroids. Purpose number one is to supply you with new minerals. Simply tow an asteroid to one of your planets and it will hit the surface, bringing new minerals into the planet. As a side-effect of the impact a number of structures on the planet will be destroyed, a number of natives and colonists will be killed and both native and colonist happiness will drop by 50 points. Of course you do not want to have an asteroid impacting on a native planet or a planet with a lot of colonists, and since you'd like to mine those minerals at a reasonable pace you'll be looking at mineral densities too when deciding which planet to treat on a meteor hit.

Option number two is somewhat more devious: tow an asteroid over to an enemy planet to crush some structures (less defenseposts are always nice) and bring down the happiness of their clans and natives. If you're planning on hitting your enemy with an asteroid always keep in mind though that you'll be giving them a lot of minerals when doing this, so don't go towing asteroids into enemy planets unless you're about to take that planet from them anyway.

Asteroids also carry Quadbenium, a new mineral which allows you -under certain conditions, read the documentation- to perform a  Q-jump. This allows a ship to "jump" to a distance anywhere between 10 and 100 LY. This jump happens before the normal host-sequence: before robbing, towing and all others. This jump will burn only Quadbenium, no fuel. Nice cheap way to move LDSFs, though there are more interesting (battle) options such as surprising your enemies by moving those 96 lightyears between you and them in one turn instead of two. Just keep in mind that there is a chance of your ship getting lost in space while performing a Q-jump.