Sails in the Space Environment

Abstract

Gossamer structures like solar sails are very fragile. First-generation solar sails will be manufactured and tested on Earth and, consequently, be required to sustain their own weight in our 1 g environment. In space they will experience what is perhaps the most hostile environment known to man—space itself. The operating “space” for a solar sail is far more than a mere vacuum, which poses problems in and of itself. Space near the Sun, which is where solar sails will first operate, is bathed in radiation from our star in the form of visible light, ultraviolet photons, x-ray, and gamma rays. The subsequent thermal extremes pose many unique design challenges. The solar wind pummels near-space constantly, and violent storms of charged particles periodically and unpredictably erupt from the Sun and engulf vast regions of interplanetary space much larger than Earth. In general, the inner solar system is not a very friendly place to operate, and it is here that solar sails will be first asked to perform.

Further Reading

NASA/CR-2002-211730, Chapter 4, author Vulpetti, where there is an introductory mathematical treatment of the sail degradation problem.

Roman Ya. Kezerashvili and Gregory L. Matloff, Solar radiation and the beryllium hollow-body sail: 1 The ionization and disintegration effects, JBIS 2007; 60:169–179 (a more comprehensive treatment of the near-Sun environmental issues.)

To consult the Australian on-line source with up-to-date solar wind information, key-in http://www.ips.gov.au/Solar/1/4. The data presented in this website is refreshed at 10-minute intervals.

The analysis of the interaction between the near-Sun space environment and the beryllium hollow-body solar-photon sail required several years and resulted in many research papers. Much of this work is cited and summarized in Roman Ya. Kezerashvili and Gregory L. Matloff, “Microscopic Approach to Analyze Solar-Sail Space Environment Effects,” Advances in Space Research, 44, 859-869 (2009).

With regard to SI, see The International System of Units (SI), also published by NIST (USA), http://www.nist.gov/index.html

The general problems of spacecraft charging and mitigation of charge effects can be found in two recent books:

• 1. Shu T. Lai, Fundamentals of Spacecraft Charging: Spacecraft Interactions with Space Plasmas, Princeton University Press, 2012

• 2. Henry B. Garrett and Albert C. Whittlesey, Guide to Mitigating Spacecraft Charging Effects, JPL Space Science and Technology Series, John Wiley & Sons, Inc., 2012

In addition, a graduate student, who completed university courses in electromagnetism, may find useful analytic approach to the complicated problems of the (1) sail floating potential, and (2) degradation of the sail’s reflective layer as carried out in Chap. 4 of Fast Solar Sailing, Springer, August 2012, by author Vulpetti. The effects of optical degradation of the sail’s reflective layer on fast sailcraft trajectories are dealt with in the Chap. 9 of the same book.