Simply accumulate 9 or more lives for one Arkonaut. This is easy to accumulate during the first Arkonaut's fifth stage of Planet Ice. Try to enter the bonus stage here, and obtain all the fruits that drop during that bonus stage for an additional life. Then, when you come out, break all the bricks. After the bonus stage, each brick will give you an additional life power up. There's enough on this stage to give you nine lives. If possible, try to get the "s" of bonus on stage four, and exit the stage through the hole just as you collect "s", this way you start stage five right at the bonus stage. You'll know they are the extra life power ups by their yellow color.