Saturday, April 27, 2013

Stairway to Heaven, Why not an Elevator?

We all know that while rockets are great, the resources required to get them off the planet and into orbit are astronomical. Shuttle missions according to NASA cost about $450 million per launch for fuel and other resources. These costs are simply too high to continue to ignore, which is why alternatives are being considered.

conceptual animation for a space elevator 
Short of suddenly discovering antigravity technology only a few ideas exist for alternatives to the costly rocket launches currently thrusting us into space today. One of the most promising proposals for solving this problem is the construction of a space elevator also known as a space ladder, space bridge, and skyhook among other things. The premise is actually quite simple. A long cord or “tether” as it’s called would be attached to the Earth around the equator. This would then stretch into space past the point of geosynchronous orbit to a counterweight orbiting fast enough to keep it stationary over one location. The high speed of the orbiting counterweight beyond the appropriate height for orbit would typically launch it out into space, but this would be prevented because of the tether. The force of this moving away from the planet would stretch the tether taught between the earth and the counterweight, permitting an elevator to ride up and down along the cable using electricity and motors rather than massive quantities of fossil fuels to transport people and material into space.

Unfortunately, the extreme tension involved in successfully implementing a plan of this nature would snap cables made of the materials we currently have available for a project like this. Despite this setback, those seeking to continue our forays into space are still looking at ways to make such a structure possible including a cable made of either carbon nanotubes or boron nitride nanotubes. These materials provide higher tensile strengths and weigh less than conventional materials making them excellent candidates for use in projects such as this. This particular challenge wouldn’t be present on lower gravity bodies such as the moon, which could accomplish the same thing with currently available materials.

Meteoroid impacts are another potential problem facing the creation of a space elevator. Because the tether would extend outside of the Earth’s atmosphere it would be exposed in places to meteoroid impacts that could compromise the integrity of the tether and potential threaten the safety of any people or materials being transported at the time. To help prevent this, a design for an extremely thin “ribbon” was proposed for the tether, reducing the likelihood of meteoroid impacts against it and providing a good deal of surface area for an elevator to use simple rollers as its means of ascension.

Weather here on Earth is also a factor to be considered especially given that the plan requires the tether to be anchored to the equator. To help avoid the issues associated with high volumes of lightning and the destructive effects of hurricanes a location for the anchor’s construction has been proposed in the west pacific.

The Future
With more research and development being done every year we grow ever closer to successfully creating a functioning space elevator. Many designs are currently being researched which includes research being done by Google’s Google X Lab and the Obayashi Corporation based in Japan which claims to be able to successfully establish a space elevator in 2050. Who knows what’s possible within the next 37 years? One thing however is sure; the space elevator is a concept that has found a permanent home here in my N3rd C0rn3r.