Japanese scientists are developing plans for a space elevator. A couple of U.S. firms have also been working on the same concept, which does not require new scientific breakthroughs, but is instead requires solving a series of engineering and materials fabrication problems. The biggest one is developing a process to make a 62,000 mile ribbon of carbon nanotubes. Carbon fiber materials are strong enough to support the loads that will be imposed on the ribbon cable, but the manufacturing processes to make the cable have to be developed.