Carbon nanotube space elevator. Conceptual computer artwork of a cylindrical fullerene (carbon nanotube) rising from the ground to Earth orbit as a precursor to a space elevator. When complete, the elevator would allow people and materials to ascend and descend to and from space. The Sun is seen in the background. The hexagonal carbon structure shown here gives fullerenes, a structural form (allotrope) of carbon, immense strength. Theoretically, a wide range of molecular shapes can be engineered at the molecular level using fullerenes. Such structures are being investigated for a wide range of technological and medical uses.