Some maps have asteroids in them. They come in four sizes.
The biggest asteroid has to be shot 4 times to break it. When it breaks,
two big asteroids will appear.
The big asteroid in his turn has to be shot 3 times to break it. When
it breaks, two medium asteroids will appear.
The medium asteroid has to be shot 2 times to break it. When it breaks,
two small asteroids will appear.
The small asteroid only has to be shot 1 time to break it.
Shooting/breaking an asteroid might give you points if the map has this option.
Don't expect to get lots of points from them though.
Asteroids can also contain items on some maps which come out if you shoot/break them.
If you run into them without shields you might die. It depends on the
options of the server.
Added comments
Now that we've got space rocks, any chance someone will make an empty, single player map, without bases even, but perhaps one robot which flys across the screen and then dissapears. And when you kill all the rocks, then you start again woith even more. What's that you say? Oh. Wrong game.
By Richard
And wrong place. The newsgroup or the Xpilot-hacks mailinglist would be a better place. :-)
By J-a-r-n-o
You forgot something. When shooting an asteroid, items may come out of it. This is something I added in 4.4.1.
By Zemyla