@jojojordi ive uploaded the source code on this scenario http://www.greenfoot.org/scenarios/5075 the reason i did it on another senario is because im working on something to do with hacking.

if you look at your code in space you have got this public void act() { if(Greenfoot.getRandomNumber(200)<10) {addObject(new robot(), Greenfoot.getRandomNumber(700), 0); } addObject(new rocket(), 300,500); } where you add the rocket that needs to be in the constructor instead of being in act like this. public space() { // Create a new world with 600x400 cells with a cell size of 1x1 pixels. super(600, 600, 1); setPaintOrder(scoreboard.class,robot.class,rocket.class,counter.class); addObject(score,100,560); addObject(new rocket(), 300,500); } that should work :P