Asked by: Max Jones, New York
First proposed over a century ago by the Russian astronautical pioneer Konstantin Tsiolkovsky, the space elevator offers a whole new way of getting into orbit. Instead of using rockets, electric lifts travel up a cable anchored at the Earth’s equator and extending up to an orbiting counterweight whose motion keeps the cable taut.
But while simple in concept, the practicalities are immense. Chief among them is the need for a cable material that’s capable of withstanding the colossal tension. It’s long been thought that carbon nanotubes would be up to the job, but new research by a team at Hong Kong Polytechnic University has shown that a single misplaced atom in the cable could radically undermine its strength.
With no real prospect of creating a defect-free cable, the search is now on for more robust materials.