BBC Focus Magazine

[worldmaker]

Introduction - "Pulses" and "Springs"

A few years ago I wrote a short science fiction story called "Pulses". Part of the story had my leading character travel amongst a series of space stations and a term I coined for them was "Spring Stations".
To me the term "spring" comes from the image of a spinning ring. A ring is used to create artificial gravity through centrifugal forces. I imagined that the term "spinning ring" would eventually shorten to "spring". A spring invokes images of life amidst the desert, a place of rest and relaxation in the midst of the barren desert of space. Ever since I have used the term to define any design of object, ring, cylinder, sphere that might use spin to create gravity.
I would like to introduce you to a variant of this image for future space travel; and, if I'm right, you may soon see "SpringShips" sailing amongst the planets and stars.

Background

I won't go into too much detail, you are probably reading this because you already have some knowledge and interest in the ideas of interplanetary, eventually interstellar, voyages. I will also assume that you are aware of the dangers to human health of long journeys in freefall, without gravity to stimulate muscle and bone strength, making it difficult to travel far unless we find a way around this problem.
One solution is to go fast and reduce time spent in space. Another way is to create the effect of gravity en-route. Ideally we ought to be doing both.
The solution we have at our disposal with current technology is the use of spin forces to simulate gravity by rotating a portion or all of a spacecraft whilst on a voyage.
There have been various notable illustrations of the concept in science fiction and fact, but they don't seem to address other problems inherent in space travel - especially the threats from micrometeorites and solar radiation.
It is my believe that a single form of vessel can be created to deal with all three problems: freefall hazards to human health, physical impact from micrometeorites and exposure to solar radiation during periods of soar flares - the SpringShip is that solution.

Design - A Disc

If we begin with the basic principle of the spring - a disc or ring shape - then we have another feature inherent in its shape which presents either a hazard or a help.
My earliest thought on the issue of ship design were concerned with the nature of the disc and its alignment. Whenever I saw other designs I noticed a tendency to adopt what I would call the "face forward" form of spacecraft.
In the "face forward" form the ship is spun along its axis to create spin and gravity is created in effect in one or more chambers or a ring on arms extending out from an axial core. As these arms are perpendicular to the axis and main body of the ship the end result is that the disc is presented face-onwards to the line of flight - presenting the maximum surface area to the front - not very healthy for the crew under any condition.
My solution to this was to tilt the ring or disc into an edge-onwards alignment. This alignment in turn automatically leads to the solution of the second problem. If a "face forward" position threatened the ship and crew from micrometeorites it could conceivably threaten them, at some points along their journey, to exposure from solar radiation. However, by tilting the ring into a horizontal position the design offered comparable protection to radiation as it does to micrometeorites.

Courses & Alignments

Most, if not all, journeys throughout the solar system will entail movement along the plane of the ecliptic - the horizontal plane on which the planets orbit the sun. This means that whenever following a course around the solar system a ship will, in most cases, present a side to the sun. By adopting my alignment for the SpringShip it becomes effective in dealing with solar radiation as only the edge of the ship is directly exposed to radiation and charged atomic particles emitted by the sun.

Shielding

There is a key benefit of an edge-on orientation for a SpringShip - only the edge has to carry the heaviest shielding.
To shield a crew against both micrometeorites and radiation would require substantial weight of material. Whatever material is eventually adopted must be heavy and dense enough to deflect or absorb the impacts of micrometeorites and their effects on the structure of the ship, and absorb or deflect radiation from the sun.
I imagine that this shielding will eventually be a mixture of physical structure and electromagnetic forces. In a manner similar to the Earth's magnetic fields, a shielding field could be broadcast around the ship, conducted by shielding plates along the rim of the disc or aerials protected from the hull at key positions.

The Springs

There is one important feature of the ship that will require most of the effort on design and construction - the spinning rings. The springs need to deal with a number of issues, not least of them being reaction torque.

Torque

So, you have a ring spinning in space. That's all right when the ring spins on its own and you have set it spinning by some action such as small rocket jets. However, when you mount the ring inside a larger vessel you have to deal with torque - the counterforce that occurs when you cause the ring, or any wheel to spin in a direction.
You know how a helicopter works? When the main rotor spins one way the natural tendency of the fuselage is to rotate in the opposite direction in reaction to the mechanical forces used on driving the main rotor around. To prevent this all helicopters have an extended tail boom and small tail rotor to push against this torque. There is a way that this can be done onboard a SpringShip - a second ring.

Two Rings

To counter torque a SpringShip has two main rings rotating in opposite directions. They don't have to be the same size, only the same mass and force on the common axis they would share.
With the freedom to vary the size of the rings the obvious solution to saving on space and weight is to have one ring smaller and seated inside the circle of the other. While the larger rings of a SpringShip would be used for accommodation and working spaces around the outer rim of the ship, a smaller ring would rotate nested inside the space closer to the axis. The key to saving weight and cost is in reducing the length of axis required to serve both rings, shortening the circumference of the inner ring and shortening its support arms, etc.

Conclusion

This is a shortened extract from the original proposal, available at www.worldmaker.org . Over many years I've attempted to identify the solutions to many problems of a sustainable, healthy, long range space voyage. Not only for the sterling adventurers of the worlds numerous space agencies and their throwaway politicians, willing to sacrifice human life in the Greater Cause of exploration, but what comes next - the long term commercial exploitation of space for everyone.
Civilians will not tolerate being treated in the same way that politicians treat their "volunteers". They demand higher standards of health, safety and reliability. The SpringShip offers a healthier environment, giving simulated gravity, more space, reduced hazards from physical impact or radiation exposure.
The SpringShip is the answer to taking mankind on the next step to the stars.
I continue to work on the financial aspects of paying for its construction.

5th of May, 2009



[Footnote: this is a resubmission of the original article following the redesign of the Focus magazine web site and forum, in July 2009.]