Space Elevato(we)rs

Next week, the Space Frontier Foundation will kick off their NewSpace 2009 Conference at the NASA Ames Research Center. The opening day of the conference, entitled ‘Space Elevator Day’ will explore new technologies and possibilities associated with Space Elevators. The conference is strategically placed between an intriguing paper published earlier this month, and the Space Elevator Games, scheduled for early August.

While the concept of a space elevator was first proposed by Konstantin Tsiolkovsky in 1895, more recently this dream is transforming from fantasy to reality. The functions of such an elevator are endless – from space tourism, to research, telecommunications, delivering payloads, and atmospheric monitoring. Perhaps the greatest function of such a device would be to empirically and directly witness the earth as an assemblage of interdependent systems.

Recently, three scientists at York University published an article in Acta Astronautica, outlining a concept prototype for a mega-inflatable tower that would act as an elevator to space. Proposed by Brendan Quine, Raj Seth and George Zhu, the 20 km tower would be made up of inflatable modules that have their roots in the Space Tether Concept that was popularized in the 1970s. The tether concept centered upon a counterbalanced mass system wherein the counterbalance would be situated in space, with a cable extending back to earth. These tethers were proposed to connect to space stations, and could be traversed by electric means. Not only does the tether give a stable system for venturing to space, it eliminates the need for chemical rockets (equivalent to 1000 tonnes of solid rocket fuel per trip) and their associated environmental impacts.

The greatest hurdle with building a space elevator, not surprisingly, is finding a material that is both strong and light enough to withstand the stress pressures of the upper atmosphere. This challenge incited Scientists examine inflatable modules, which are increasingly being used in contemporary spacecraft due to their simultaneous lightness and strength. Carbon nanotubes are also being explored for such a purpose due to their high strength, however, the expense and limited quantities of such a material suggests the inflatable modules are more viable. The inflatable tower would operate like a ‘telescoping wand’; each segment individually pulling out and locking into position. Pressure balancing and gyroscopic stabilization control systems would allow for a consistent position. These control systems would also enable the tower to counter natural forces such as strong winds by causing the structure to lean into the winds.

The proposed space elevator would be built up from the earth's surface in 150m pressurized segments, that are then stacked. Kevlar-polyethylene, which is already being produced in bulk, would be used to enclose and maintain the gas pressure. Gases such as air, helium and/or hydrogen would be used within the structure. The estimated weight for the 20km tower is approximately twice the mass of a supertanker. The York University scientists posit that the tower could theoretically be extended to 200km. It would take tourists and researchers around 40 minutes to reach the top of the 20km tower and offer a view of 600km in any direction.

The burgeoning space tourism industry is currently lead by ‘rocket’ ventures of Virgin Galactic and Project Enterprise. Space elevators, however, provide a more environmentally sensitive and safer route to space, inciting research by the Liftport Group and Japan Space Elevator Association. Recognizing the value of space elevators, NASA partnered with the Spaceward Foundation in 2004 to hold the inaugural Strong Tether and Power Beaming Competitions. The current Elevator 2010 challenges scientists to reach 1000m high while climbing at 5m/s (for a $2M prize!). While the ‘blue marble’ photograph of the earth taken in 1972, revealed the earth as an interdependent system of weather, habitats, and vegetation, space tourism has the power to frame both the relative complexities and vulnerabilities of earth.

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