In the September 2004 issue of Trends, we reported on the concept of gaining easier access to orbit, and beyond, by way of a space elevator. The idea goes back to at least the 1800s, but modern technology has brought it out of the realm of fringe science fiction and into the engineering mainstream.
To recap: The objective of a space elevator is to make access to space easy, safe, and affordable. The five basic design elements of an operating space elevator are as follows:

• A platform, resembling an offshore oil rig, featuring a very tall tower, will be constructed at the equator, most likely in the middle of the Pacific Ocean.
• A thin ribbon stretching into space will rise from the platform to the sky.
• A massive counterweight will be located on the other end of the ribbon, 62,000 miles away.
• Climbing vehicles, equipped with solar panels to produce electricity from light and power the electromagnetic propulsion system, will ascend and descend the ribbon.
• High-powered, ground-based lasers aimed at the lifters’ solar panels will provide power.

The laser and power transmission technologies for the space elevator already exist and are known to work. The ribbon is the key to making the project feasible, and it is under development in labs around the world. It will most likely be made of carbon nanotubes, because they promise the highest strength of any material known and can withstand the stresses involved in tethering an object in space to the earth over an extended period.

The reusable climbing vehicles will be about the size of railroad cars and will travel hundreds, or potentially even thousands, of miles an hour. At top speed, they could reach geosynchronous orbit in as little as five hours, according to the official Science@NASA Web page. However, at more realistic speeds, it might take from five to seven days to make the trip.

“Geosynchronous orbit” simply means that the object is rotating around the Earth at the same rate that the Earth rotates, once every 24 hours. According to Investor’s Business Daily,¹ the elevator will rely on gravity and the centrifugal force of the earth’s rotation to keep the ribbon taut.

The climbing vehicles will shuttle people and cargo up to a...