J. Heidmann et C. Maccone, ASTROSAIL AND SETISAIL - 2 EXTRASOLAR SYSTEM MISSIONS TO THE SUNS GRAVITATIONAL FOCUSES, Acta astronautica, 32(5), 1994, pp. 409-410
We use the three fundamental concepts of the gravitational lens effect
of the Sun; the solar sail propulsion of spacecraft; and the galactic
belt of life to present extrasolar system missions aimed at an ultra-
high gain investigation of the galactic centre (ASTROSAIL) and of the
sky direction most likely to reveal extraterrestrial civilizations mor
e advanced than ours (SETISAIL).