The free spins feature is triggered by getting three or more scatters, but they must appear adjacent to each other (there are red rocket scatters that appear on all 5 reels, while the blue and green space ships appear on reels 3, 4, 5) three scatters give you a bonus game where you select a spaceship and alien and there your chosen character will beam up the bonus game type. Such as the beam em up contest. There all 5 aliens will be competing in a neighbourhood beaming up as many items and each one is worth some coin wins, at end of it the placings are sorted 1st place, 2nd place, 3rd place, 4th place, 5th place.
Your prize is whatever the amount of coins you collected. Abducting humans pays the most, while simple items such as a pot plant, teddy bear, a cat are worth less.
Some items to see on the reels are flaming cherry, flaming orange (represents the sun), console, plumb Saturn, watermelon, as you can tell the fruits have been made to look like space objects.
I gotta say this one was one of my favorite 9 liners and I always had to have some spins on it during sessions. One of my better wins was when I had 3 red scatter rockets and then this led me to beaming up the cop character and paid 100x Bet. But the best bonus I had was 203x Bet. Keep a look out for the destination bonus which is a more rare bonus than the contest, because you can get higher paying characters related to the destination. Including the abduction of the queen if you visit London. Or if you go to Egypt then get the mummy.