Aerospace engineer Brad Edwards’s plan for a space elevator
centers on a carbon-nanotube-composite ribbon 62,000 miles
long (roughly eight times longer than Earth’s diameter),
three feet wide, and thinner than a newspaper page. The competing
forces of gravity at the terrestrial end of the elevator and
centripetal acceleration at the deep-space end would keep the ribbon taut
and stationary over a single position at Earth’s equator.
Climbing vehicles powered by Earth-based lasers striking solar cells
would haul cargo and people to various orbits. If a climber
released a cargo or passenger vessel at the far end of the ribbon, the craft
would have enough velocity to travel to the moon, Mars, Venus,
or the asteroids. At a cost ranging from $6 billion to $24 billion,
Edwards says that the elevator is within the means of
several of the world’s governments as well as some large
private companies.