Space-habitat illuminators with non-imaging optics

William A. Parkyn

doi:10.1117/12.448822

19 November 2001 Space-habitat illuminators with nonimaging optics

William A. Parkyn

Proceedings Volume 4446, Nonimaging Optics: Maximum Efficiency Light Transfer VI; (2001) https://doi.org/10.1117/12.448822
Event: International Symposium on Optical Science and Technology, 2001, San Diego, CA, United States

Abstract

The strongest known material, carbon nanotube, has inspired designs of spinning space habitats reaching radii of 1000 km. Known as the Space Ring, a cylinder of such radius, with a 'short' 500 km length, has an 'open sky' geometry that only self-occludes a third of the view of the stars, as they spin around twice per hour. Sunlight is unsuitable for illuminating the Ring interior because it cannot be turned off. Instead, the Ring axis is sideways to the sun, and solar-cell concentrator troughs cover its exterior to provide power for a central illuminator. Because the inside living space is p times the projected cell area, illumination effectiveness is at a premium, even if the electrical efficiency of the cells is 50 percent, and enormous storage capacity accounts for 'night-time' sunlight. Only a quarter of the light output of a central isotropic emitter would fall on the Ring, so that nonimaging optics is called for. Overall luminaire size (and cost) is reduced by increased emitter luminance, but considerations of eye safety oppose this. An ideal CPC of revolution would produce a rectangular 'sun' with 4:1 aspect ratio, fixed overhead in a blue sky, unable to generate rainbows, sunrises, or sunsets.

Citation Download Citation

William A. Parkyn "Space-habitat illuminators with nonimaging optics", Proc. SPIE 4446, Nonimaging Optics: Maximum Efficiency Light Transfer VI, (19 November 2001); https://doi.org/10.1117/12.448822

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available