On Star Trek, if you want to go from one deck to another, you enter a “turbolift” and tell it where you want to go. However, many people have speculated that one day you’ll ride an elevator to orbit instead of using a relatively crude rocket. The idea is simple. If you had a tether anchored on the Earth with the other end connected to a satellite, you could simply move up and down the tether. Sound simple, so what’s the problem? The tether has to withstand enormous forces, and we don’t know how to make anything practical that could survive it. However, a team at the International Space Elevator Consortium could have the answer: graphene ribbons.
The concept is not new, but the hope of any practical material able to hold up to the strain has been scant. [Arthur C. Clarke] summed it up in 1979:
How close are we to achieving this with known materials? Not very. The best steel wire could manage only a miserable 31 mi (50 km) or so of vertical suspension before it snapped under its own weight. The trouble with metals is that, though they are strong, they are also heavy; we want something that is both strong and light. This suggests that we should look at modern synthetic and composite materials. Kevlar… for example, could sustain a vertical length of 124 mi (200 km) before snapping – impressive, but still totally inadequate compared with the 3,100 (5,000 km) needed.
Continue reading “Next Floor: Geosynchronous Satellites, Orbiting Laboratories”
The big expense in getting people to orbit or the moon or any other space destination is the cost of escaping the Earth’s gravity. One often-proposed solution involves building a giant space elevator from some point on the Earth to orbit. That sounds great, but the reality is the materials needed to make a giant stalk reaching from the ground to orbit don’t exist today. Cables or other structures for such an elevator would have to be so impossibly thick as to break under their own weight. However, a recent paper from a researcher at Cambridge and another at Columbia suggest that while you can’t build an elevator from the Earth’s surface to orbit, we may have the technology to build a tunnel that anchors on the moon and lets out in Earth’s orbit.
Before you dismiss the idea out of hand, have a look at the paper. A classic space elevator proposal has one point on Earth and the far end balanced with a counterweight keeping the cables under tension. The proposed lunar elevator would minimize these problems by having most of the bulk in space and on the moon.
Continue reading “Moon Elevator Could Be Sooner Than You Think”
Space elevators belong to that class of technology that we all want to see become a reality within our lifetimes, but deep-down doubt we’ll ever get to witness firsthand. Like cold fusion, or faster than light travel, we understand the principles that should make these concepts possible, but they’re so far beyond our technical understanding that they might as well be fantasy.
Except, maybe not. When Japan Aerospace Exploration Agency (JAXA) launches their seventh Kounotori H-II Transfer Vehicle towards the International Space Station, riding along with the experiments and supplies for the astronauts, will be a very special pair of CubeSats. They make up the world’s first practical test of space elevator technology, and with any luck, will be one of many small steps that precedes the giant leap which access to space at a fraction of the cost will be.
Of course, they won’t be testing a fully functional space elevator; even the most aggressive of timelines put us a few decades out from that. This will simply be a small scale test of some of the concepts that are central to building a space elevator, as we need to learn to crawl before we can walk. But even if we aren’t around to see the first practical space elevator make it to the top, at least we can say we were there on the ground floor.
Continue reading “One Small Step For A Space Elevator”
It’s the stuff that Science Fiction is made of: an elevator that climbs its way into space rather than needing a rocket to get there. Can it be done? No. But this Kickstarter project aims to fund research that will eventually make a space elevator possible. They’re already way over their goal, and plan to use the extra funds to extend the reach of the experiments.
A complete success would be a tether that reaches into space, held taught by a weight which is pulled away from earth by centrifugal force. That’s not really on the radar yet (last we heard humans weren’t capable of producing a substance strong enough to keep the tether from snapping). What is in the works is a weather balloon supporting a ribbon which a robot can climb. The team isn’t new to this, having built and tested several models at University and then in a start-up company that closed its doors a few years ago. Now they’re hoping to get a 3-5 kilometer ribbon in the air and to build a new robot to climb it.
For now we’ll have to be satisfied with the 1000 ft. climb video after the break. But we hope to see an Earth-Moon freight system like the one shown in the diagram above before the end of our lifetimes.
Continue reading “Can A Kickstarter Project Actually Build A Space Elevator?”
The space elevator may be a very real possibility within our lifetimes. Previously the stuff of science fiction novels, scientists and engineers around the world will continue their discussion at a conference in Japan this November. The space elevator’s basic design would include a cable that is anchored to the Earth’s surface, and on the other end, tens of thousands of kilometers away, a counterweight for balance. The space elevator could be used to solve many different problems, from nuclear waste disposal to powering homes with solar panels.
The technology driving the development of the space elevator is the carbon nanotube. Its lightweight properties and tensile strength, over 180 times stronger than steel cable, make it the ideal cable for the space elevator. Currently there are several logistical problems, which range from designing a carbon nanotube strong enough to support the elevator to finding an ideal site to design and build the elevator, which would require international consensus and input. Several organizations are working on space elevator designs, and NASA is holding a $4 million Space Elevator Challenge to encourage designs.