Even tools dropped by an astronaut. Scientists believe there are now half a million pieces of debris the size of a marble or bigger and each piece has the potential to do some serious damage. Last year the International Space station was hit. This chip in a window was caused when it was struck by a tiny fleck of paint. But the bigger pieces ofjunk are a more pressing problem. This european satellite, the size of a double decker bus, suddenly stopped working in 2012. Since then, its been circling the earth, threatening other key satellites in its path. The problem is going to grow. Its going to grow because collisions are going to take place in the orbital environment. Were going to lose the satellites that we rely on. Thats going to be costly to us, its going to be costly to the future generation. All eyes are now trained on the remove debris spacecraft. If the technology works, the hope is future missions can be scaled up and the space clean up can begin. Rebecca morelle, bbc news. Ne