Interview on Space Elevators with Mr. Ben Shelef - founder of the Spaceward Foundation which is a public-funds non-profit organization dedicated to furthering space science and technology in the public mindshare and in educational curriculums.

ASG: What is Space Elevator and what is its purpose? 

Spaceward: The Space Elevator is a revolutionary space access technology, capable of delivering staggering amounts of payloads to space in a safe and benign manner, without any of the problems that plague rocket based travel.  The overview below considers a concrete design for a 20-ton capacity Space Elevator, but Space Elevators are infinitely scalable one can just as easily construct them ten times or one hundred times larger.

The Space Elevator structure is a tether, about 1/4" (0.6 cm) in diameter, and about 60,000 miles long, one end attached to the ground (or more precisely, to a ship on the equator) and the other end attached to a counterweight in space. The structure (tether and counterweight) spins in unison with earth, completing one revolution every 24 hours, and this rotation keeps the tether taught by the pull of the counterweight. For an earth-bound observer, the tether seems to simply stretch straight up into space, with the counterweight pulling up on it as if by magic. Were the tether to be released from the anchor, it would fly upwards into space, following the counterweight. For various reasons, outside of the atmosphere, the tether is spread out to be very wide and very thin (keeping the same cross sectional area) making it look more like Saran Wrap than like a round tether. In such a configuration, it is referred to as a ribbon.

In order to access space, vehicles called climbers, travel up the ribbon using mechanical traction wheels, powered by electric motors and a photo-voltaic array. The climbers move at about 200 km/h (about 120 mph), and the ride to GEO takes 4 days. Since solar light is not powerful enough to drive the climbers straight up the ribbon, the design has the photo-voltaic array placed at the underside of the climbers, and a strong beam of light projected from the ground and providing the source of power. Since the power source is left on the ground, a climber can be 25% structure and 75% payload in contrast to the 1-5% payload numbers that are common with rocket based launch systems.

In this 20 ton capacity design, the tether weighs about 1000 tons, and the counterweight weighs another 600 tons. For a sense of scale, the international space station weighs about 500 tons, and a Space Shuttle weighs about 2000 tons at liftoff, and can carry about 20 tons to space.

ASG:  How will you further space science and technology in the public mindshare and in educational curriculums? 

ASG:  How are the projects finanaced and how can people help? 

Spaceward:  We're sponsorship based.  Our current partners are very excited about SERS, since they can easily see the exposure potential. We are now looking for more sponsorship - SERS will not come for free, and will have significant construction and operating expenses. We intend to create a lot of buzz around the Space Elevator, have high-attendance (100,000 visitor) events, and get corporate sponsors.

ASG: Ben, thank you for talking to ASG via email (May 29, 2005).

Read about the Space Elevator Games. 2006 Space Elevator Competition.

Books: 

The Space Elevator: A Revolutionary Earth-to-Space Transportation System
by Bradley C. Edwards, Eric A. Westling
From Amazon.com, Amazon.co.uk, Amazon.ca

A Vision of Future Space Transportation by Tim McElyea, David Brin
From Amazon.com,  Amazon.co.uk, Amazon.ca

Goto Space Projects and Info Home Page

Copyright © 2000-2008 Vic Stathopoulos. All rights reserved.
Updated: Saturday 5th, July, 2008