I have an idea to complicate matters when playing in an asteroid field.
Extra equipment required: 1D6, scatter die
Procedure: After placing the asteroids and ships, determine direction and speed of asteroid drift. Roll the scatter die. This will be the direction all asteroids move throughout the game. If the scatter die comes up 'bullseye', the asteroids remain stationary throughout the game.
Next, roll the D6 to determine asteroid speed (applies to all asteroids throughout the game). Result of 1-2, asteroid speed = 1. Result of 3-4, speed equals 2 and a result of 5 or 6 indicates a speed of 3.
In the end phase of the turn, move each asteroid the indicated amount using the Range Ruler in the direction indicated on the scatter die. If an asteroid reaches the edge of the playing surface, place it on the table edge directly opposite the spot where it went off the board. Resume it's movement next turn. (think the old old video games like Asteroids).