Carbon nanotubes are a novel material that is 100 times stronger than steel while only one-fourth its weight and has electrical conductivity as high as that of copper. If fibers could be made using carbon nanotubes, theoretically, these fibers could surpass the performance of existing carbon fibers. However, maintaining the superior properties of carbon nanotubes in fibers is very challenging. A research team has recently developed a low-cost fabrication technology for carbon-nanotube-based composite carbon fibers with extremely high tensile strength and high modulus.