Salvage

Space junk has gotten so bad that there are now private salvage companies that work on a contract basis with the government to collect and dispose of the debris. The companies have special, heavily shielded ships that can withstand small impacts of debris while they capture the larger stuff. A young pilot and the crusty owner of Salvage-One find something in orbit they didn't expect, and it leads them on an adventure to the moon, then another system, and then to Earth's only hope to stave off an invasion.