Raymond Gallun 
The Planet Strappers [EPUB ebook] 

Nelson and Ramos sped on toward Mars in their tiny plastic-bubble spacecraft. They were on the alert – it didn’t pay to take anything for granted in the Big Vacuum…The way between the worlds was mostly empty space – except for the outlaws of the void who drifted, patiently and vengefully waiting for a victim, then struck! Nelsen and Ramos tensed – blips on the radar screen! Maybe meteors… More blips – and fist-sized chunks of rock flicked through their fragile vehicles. Air puffed out… and Nelson and Ramos were fighting for their lives… A Million Miles Beyond the Moon!