Tuesday, November 29, 2011

Space Station "DNA" - David H. Mitchell (941227)

Space Station "DNA"

Copyright (C) 1994 by David H. Mitchell


Permission is hereby given to freely distribute this document provided it is not altered in any way.


The first step in building a flexible, viable Space Station is to unlearn all previous Space Station goals, methodologies and designs. Instead, we look to the most basic things we know that do work: life and free market economies. From this, the design of a long term viable, low cost and com- pletely flexible space station system becomes obvious. The basic design becomes a DNA-like backbone of support modules onto which extension units are added. By employing terrestial "office park" rental policies, if becomes possible to have a self-adjusting, self-expanding space station that acts as a model for additional space station and space colonization enterprises. NASA sets an initial standard, provides the initial framework for the first Space Station DNA, then acts as a coordinator and Association manager for the first Space Station DNA operation. NASA then offers low cost licenses for addition- al Space Station DNA. Concepts of standardized manufacturing make for easy replication of Space Station DNA components and additional stations.


Huge amounts of manpower, time and money have resulted in 2 Space Station attempts so far (Freedom and Alpha) that represent a compromise between available money, mission objectives and politics. The result has been a series of disappointments for idealistic designers, space advocates, NASA, the Congress and the tax-paying public. The basic problem has been lack of vision as to what Space Station must accomplish in the long run to be an acceptable investment in the short run.

By using a simple ideological and structural design, we can employ the best elements of how life is constructed and how ecomonic opportunity is created. This Space Station "DNA" approach makes it possible to put the beginnings of a long term viable Space Station in orbit in as little as 3 years without wasting money and without building in limits to future growth, design or capabilities.

To make this work, we use DNA-like backbone structural elements that can be made on earth, in orbit or on the moon - whichever is least costly. These units are then moved to where the space station is to be assembled. The backbone units provide a standardized interface for mechanical coupling, needed facilities and economic activities. The economic modularity is done on the same basis as an "office park" and "shopping mall" in which the entire Space Station DNA allows for rental of areas with the necessary initial costs underwritten by NASA as an experimental project to get Space Station DNA "off the ground", literally.

Space Station DNA Physical Structure:

Space Station DNA is composed of two types of standard units and one type of customized unit. The standard units are called Backbone Units and End Caps. The custom units are called Condo Units but may also be mass-produced in many cases based on need. Each Space Station DNA is build from two End Caps and one or more BackBone Units. The Backbone Units are designed so that easy expansion is possible by removing one End Cap, adding a Backbone Unit and then putting the End Cap at the new end of the chain. Non-standard Condo Units are attached to the Backbone Units by interested parties for scientific, educational and commercial use.

Each End Cap has thruster consumables, station keeping capabilities (such as thrusters and flywheels) and communications link facilities. The purpose of the End Caps is to provide a logical beginning and end to each Space Station DNA and to provide the basic positional and communications stability for the physical structure. Each End Cap also has a Space Shuttle docking adapter.

Each Backbone Unit is a cylinder 3 meters in diameter and 3 meters long. When connected together, they form a spine of 1 or more units with an End Cap at each end. Each Backbone Unit has a 2 meter hollow interior and an airtight door/hatch at one end. Additionally, one wall of the Backbone Unit has a 2 meter by 1 meter door/hatch to which a Condo Unit may be attached. The Backbone Unit has 6 "Utility Service" linkages each providing the capability for 120 vac power, 14.7 psi earth-normal air, fiber-optic SolNet (Solar System Internet) standard communications link and distilled water. The pur- pose of each Backbone Unit will be to act as an interface in all ways between the customized (or standardized) Condo Units and the Space Station DNA. The importance of Backbone Units can not be overstated. By being of identical standard design, it allows for easy volume manufacturing first on earth, then in orbital or lunar facilities. Since each Backbone Unit has 6 complete "Utility Service" linkages, multiple redundancy (both physically and economic- ally) is achieved. This also allows for high flexibility as to which Condo Units are consumers of services and/or producers of services. BackBone Units are designed for 6 possible Condo Unit door/hatch positions so that a large Space Station DNA will have each successive Condo Unit located next too, but 60 degrees rotated from, the prior Condo Unit. The resulting Space Station DNA will have a DNA-like spiral appearance.

Each Condo Unit is not longer than 20 meters in length and not wider in diameter than 2.5 meters in length. Condo Units can be of standardized or custom design as dictated by function. A solar power producing Condo Unit, for example, might consist of solar panel arrays and power conversion equip- ment and provide one of the 6 "Utility Services" power feeds under license. A science laboratory, for example, might be a shorter unit with facilities for manned habitation for short periods. Each Condo Unit would be installed, based on the designs of its owner for the needs of its owner. Condo Units are either consumers or producers of "Utility Services". A minimal Space Station DNA needs enough a Condo Unit to provide 1 set of utility services: power, air, communications and water. In a large scale Space Station DNA, multiple Condo Units would provide "Utility Services" to a large number of Condo Units which are consumers of utilities but which may product scientific information, educational services or commericial services and products.

Space Station DNA Economic Structure:

The concept is to employ free market economics and business methods which have worked on Earth as a model for Space Station DNA. To do this effectively requires defining the minimal utility services required and to design-in competition even at these basic levels. Ownership of the End Caps and Backbone Units stays with the developer (in the real estate definition of the word) of the Space Station DNA. The developer rents one Backbone Unit to which a Condo Unit is attached. So, renting a Backbone Unit is much like renting a plot of land or an office in an Office Park, Industrial Park or Shopping Mall. And, the Condo Unit can either be purchased or rented - much like one owns or rents a home or office.

NASA plays the pivotal role in getting Space Station DNA off the ground (literally) by being the first Developer. As Developer, NASA contracts for construction of the two End Caps, 6 to 12 Backbone Units, a Science Condo Unit, a Utility Services Condo Unit and a Hotel/Habitat Condo Unit. Note that there is no requirement for continuous manned capability init- ially. This reduces cost until SSTO transport goes online by reducing Space Shuttle flights to realistic capabilites. ELV's may be used to put most of the pieces in orbit, if desired.

NASA's role is largely that of being a standards coordinator and investor in the first experimental Space Station DNA. As cost to orbit is reduced and the number of BackBone Units increases (to meet demand), rental costs will decrease. Note that the evolution of the first Space Station DNA will be gradual, starting out as a NASA space station and transforming into a multi-national prototype continuously manned space colony. Several Space Station DNA's in close proximity can provide an economically viable space community.

Important elements of the economic model upon which Space Station DNA are based include NASA initially acting to subsidize Space Station DNA growth by offering low cost long term rental agreements on Backbone Units. By renting a Backbone Unit at $1,000 a month on a ten year lease ($120,000 total committment), it becomes within the reach of the top 20,000 businesses to consider renting a space - even before putting a Condo Unit in place. This is not too different than selling lots of land onto which future homes will be built. Since the Backbone Units are essentially hollow shells with two door/hatches and Utility Services connections, it may well be that the NASA subsidy might be fairly small. Many corporations, both domestic and Inter- national, might invest $120,000 for reasons as simple as promotion and ad- vertising. Clearly, any business that does this shows their serious about investing in the future. Because entertainment and sports generate huge annual revenues, it would be logical for television networks, movie studios and cable TV companies to rent facilities so as not to be left out in the years to come.

The important economic consideration is that Space Station DNA has clear-cut lines of ownership. The first experimental Space Station DNA has End Caps and Backbone Units owned by NASA (which means owned by the American People). And, a few Condo Units will be owned by the American People to give this first station minimal viability.

Contracts will be let by NASA by module on a competitive quote basis. So, End Caps will be specified by function, not final design. Backbone Units will be handled the same. The initial Condo Units will be custom quoted. It is strongly recommended that the End Cap and Backbone Units be procured from two contractors that are lowest bidders. As is customary in industry, you have at least 2 sources for critical compoents of anything you are building.

Utility Service licenses are granted to those who wish to provide utilities by the Space Station DNA owner. This means NASA for this first experimental station. Since up to 6 competing Utility Service providers are possible, this encourages competition and innovation in basic infrastructure without risk to Space Station DNA viability. We can expect all current terrestrial utilities companies to bid aggressively for the chance to be first. Indeed, a communications license bid from AT&T, for example, might well cover a significant fraction of NASA's costs for the initial Space Station DNA.

The key to getting earth-based investment into space is to offer a viable long term economic platform in space. Space Station DNA does this.

Timetables and Costs:

Since the central theme behind Space Station DNA is to build the station as it is cost effective to do so, we need therefore to look at what must be done now and done later.

What we should do in 1995 is commit to the concept and define the overall interface specifications for the modules. This should result in request for quotes for all necessary components going out by the end of 1995. All quotes should be based on having finished modules by the end of 1997. Two year design and build cycles are completely possible based on the simple design specifications and modularity. ELV's and Shuttles should put the units in orbit in early 1998 for assembly in mid to late 1998.

During 1995 NASA should open up the Space Station DNA 1 for rental agreements and for Utility License Auctions. The highest bidders to provide utility services based on design and comsumer cost specifications should be awarded. Note that this actually creates a revenue stream to demonstrate for other Space Station DNA developers after NASA to use for business planning purposes.

This timetable rewards fast, reliable performance on the part of contractors and provides a long term viable experimental space station well before the turn of the century.

Costs would be less than current space station estimated costs. Backbone Units may initially cost up to $10 million each but can easily drop to $100,000 each in mass production. End caps may initially cost $100 million to design and build and can benefit from an order of magnitude drop when mass produced. The Science Condo Unit, Utility Services Condo Unit and Hotel/Habitat Unit can each cost anywhere from $200 million to $500 million based upon design criteria desired. Note, this brings the total Space Station DNA 1 component costs to $900 million to $1.8 billion based on final design. Number of ELV launches needed to put the components in orbit is about 8. Number of shuttle launches need to assemble the station should be 3 or 4. This makes Space Station DNA very affordable - especially due to its long term physical and economic viability.


By choosing the right criteria and goals, the Space Station DNA naturally evolves as an affordable, doable Space Station experiment with long term physical and economic viability. For less than one billion dollars a year, we can have a functioning, open-ended space station in orbit in 4 years. The modularity of Space Station DNA makes each additional space station easier to produce at lower cost. By encouraging free market economics, economically self-sustaining Space Station DNA's appear viable within 10 to 15 years.

Author:  David H. Mitchell  internet email: David42@bix.com

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