I have a the following problem with KSP and I cannot find a way to make it work. When I upgrade the Launchpad, I can add more parts to the spacecraft, but I can not go over 18 tons of mass. Even if I upgrade to level 3, I am restricted to 18 tons. I have read that this is a 64-bit problem, however, I believe that Steam currently only allows for 32-bit. At least I can only see the KSP.exe and not KSP_x64.exe in the respective folder. Any advice? Version: 1.04 on Steam, downloaded & installed July 23rd 2015 OS: Windows 7 64-bit