I attended the 10/11 Space Elevator Games presentation at the SLC Library last Thursday. The Third Space Elevator Elevator Games are set for next Fri-Sun at the Davis Co Fairgrounds. See the Utah Astro wiki current events page for more details. http://www.spaceward.org/ http://www.utahastronomy.com/Current_observing_events The following summary is a combination of the presenter's slides and my own interest in the topic. Davis County Fairgrounds got the games as a last minute substitution. The university sponsor at the original Las Vegas site bailed at the last minute. It is likely that practical space elevators will come to futurition within the next ten years. Current design efforts are based on the model for a 13 ton lifter designed by Bradley C. Edwards during 2000-2003. http://www.spaceelevator.com/docs/521Edwards.pdf http://www.amazon.com/Space-Elevator-Earth-Space-Transportation/dp/097465171... The elevator lifter design consists of a solar or microwave panel and a payload bay on either side of a 3 inch nanocarbon ribbon. Laser or microwave power is beamed up from the surface to power the climber to geosynchronous orbit. The practical ability to fabricate a 35,000 kilometer nano-carbon ribbon currently does not exist. Kelvar ribbons of up to 40 kilometers in length currently can be fabricated and are the basis of geosynchronous skyhook launcher concepts. Present technology can continuously fabricate nano-carbon ribbon at about 3 centimeters a minute. A finished cable of 35,000 km would weigh less than a shuttle or planned Aries V satellite payload (45,000 metric lbs). The cable would be lowered to Earth from above geosynchronous orbit and then spliced into a continous ribbon fabrication facility. The ribbon is then spooled into a continous loop. This assures that damage to the ribbon that may accure from low-Earth orbit human space junk or meteor impacts is continously rotated out of the service. A carbon nanospace tether is scalable, by simply stringing cables next to each other. In earlier years of operation, 1/2 the climber payload will be devoted to hauling additional cables to orbit - resulting in four to six years with the ability to climb 200,000 lbs (the weight of a 747) to orbit at one time. In light of recent concept design and carbon-nanofiber developments, NASA awarded $4 million to the Spaceward Foundation competition as prize money to spur further first-order designs for the tether climber. There is a second competition for tether strength. A third high-school competition involves light-power racers on a 100ft horizontal track. The Edwards design has an initial construction cost estimate of $10 billion - less than two-thirds of one-year of funding for NASA. The last lb-to-orbit cost estimate is $100 per lb. About 20 universities will compete. Each competitor will have a half-hour to reach the top of a ribbon strung from a 400 ft crane. (Seeing a 400 foot crane is probably worth the trip alone.) In contrast, the Federal Aviation Administration (FAA) Air Traffic Control Tower (ATCT) at the Salt Lake City Airport is 328 feet tall. The first-half of each hour is for setup and breakdown; the first half for running up and down the cable. Hence, the competition runs for two 10 hour days. The Space Elevator Games used searchlights as power source. the third Space Elevator Games also will use both infrared lasers and microwave power sources. As a result, only small apeture binoculars are allowed onsite. Video cameras are allowed. On a macro scale, completion of a space elevator with practical Earth-to-orbit costs equal to current commerical air transportation ($2-$5 per kilogram) would be history tranforming event. The Spaceward presenter emphasized the potential to mine asteriods and diffuse goals such as humanity moving into the solar system. The weight of the Edwards design concept is low-enough for current rockets to ship the ribbon tether to lunar or martian orbit - opening other robotic and human exploration possibilities. Personally, I tend to discount such spacefaring futures, since for most basic minerals, like iron or gold, current proven reserves are sufficient for between 1,000 and 3,000 years, including serving population increases. IMHO, the real potential for space elevator technology relates to alternative energy futures. Fossil fuel based-economy is on its way out with global warming. A U.S. nuclear fuel based economy involves building around 2,000 reactors in the U.S. alone. Although second generation INEL reactor designs do not have the risk of meltdown as compared to first-generation light-water reactors, after fifty years of nuclear power, we still have to begin disposing of the existing inventory 100,000 tons of high level nuclear waste. Yucca Mountain remains uncompleted. Lunar based power systems are technically and economically feasible, but are considered too "far out" to accepted by decisionmakers. Orbital space power stations were retired from the domain of feasible energy solutions in the 1980s because of the prohibitive cost of lifting tons of construction material to Earth orbit. If it comes to futurition, even a 13 ton design has the lift capacity to put Earth-orbit space based power back on the table - and to provide the U.S. with the alternative for a sustainable energy future. Admission next weekend at the Davis Fairgrounds is $10. The SLC library presentation will be repeated next Thursday, Oct. 17. - Kurt P.S. - I have not done heavy fact-checking on this note. _______________________________________________ Sent via CSolutions - http://www.csolutions.net