New Scientist has published a report which deems the concept of a space elevator unsound. This adds another salvo to the eternal "Would It Work?" debate which has been raging through the science (not to mention the science fiction) community for years. Many people have proposed a space elevator as a permanent, cost-effective alternative to using various forms of flight to reach space. In the typical scenario, a tether is attached to the planet (firmly, one would hope) at one end, and to a counterweight at the other end. The counterweight is a big object in geosynchronous orbit, which keeps it in a fixed position above the anchor pad. A variety of different vehicles could then traverse the tether, ferrying passengers and materiel into space at a fraction of the cost of, say, a shuttle launch. Ideally, a space elevator would also be quite a bit safer than either manned or unmanned flight, since there are fewer points of failure, and more opportunities for safety points. The New Scientist article cites the Coriolis force as the most likely cause for failure of a space elevator. The Coriolis "force" makes a moving object appear to be deflected, when it is viewed from a rotating point of reference. For example, imagine that you are standing at the center of a moving (i.e. a rotating point of reference), and you have a friend standing directly above the carousel in the bucket of a crane. If you throw a ball directly towards the edge of the carousel, your friend in the crane will see the ball travel in a straight line from the center of the carousel to the edge. However, from your perspective, the ball's trajectory will appear to be deflected to the side into a curve. The planet Earth, of course, is a rotating point of reference. If you step off it and start climbing a bit of rope into the sky, the Coriolis force will start to pull you off to the side, even though the rope itself is holding still (from the perspective of an Earthside observer). This movement could cause the elevator to begin swinging back and forth, and you don't want it to do that. One measure to prevent this oscillation from getting out of control is to slow down the rate of travel. The slower you travel, the less effect the Coriolis force will have, and the more time the counterweight will have to shift and counteract the oscillation. Unfortunately, scientists in the New Scientist article have crunched the numbers and decided that this puts the optimal transit time at about twenty four days. This would put a damper on one of the prime benefits of a space elevator, which is the potential for a relatively rapid turnaround time. It's hard to deny that the feasibility of constructing a space elevator on Earth is poor. Between the hazards posed to the tether by air traffic, space junk, and the Van Allen radiation belt, and the risks posed to nearby populations by a falling tether, a space elevator is better suited to uninhabited planets like Mars. (Not that a tether failure on Mars would be a non-trivial event - see also: Kim Stanley Robinson's Mars trilogy.) Of course, the New Scientist has pooh-poohed the concept of a space elevator in the past. Not everyone is deterred by the challenges - the First Annual Japan Space Elevator Conference was held in Tokyo last November, and the LiftPort Group ( "The Space Elevator Companies") has a countdown timer posted on their website.