Solar Sailing to the Sun's Inner Gravity Focus: A Design Study

摘要

The next extrasolar destination after the heliopause at 200 AU is likely to be the Sun'sinner gravity focus at 550 AU. At solar distances beyond this point, electromagneticradiation from celestial objects occulted by the Sun will be concentrated in a highlyamplified narrow beam. This effect of general relativity will be of interest to SETIresearchers, astronomers seeking to image nearby extrasolar planets, explorers of the nearfringe of the Oort Comet Belt and designers of interstellar relays. In this paper, analgorithm is developed allowing one to calculate interstellar cruise duration to thisdestination for solar sail craft launched from initially parabolic solar orbits and alwaysoriented normal to the Sun as a function of perihelion distance, payload mass, sail area,reflectivity and areal mass thickness. It is assumed that a significant fraction of payloadmass is devoted to a xenon-fueled radioisotope electric rocket to allow cross-rangecapability ＞550 AU from the Sun. It is shown that travel times to 600 AU approximate 5-7 decades for reasonable values of the parameters considered.