FOCAL - Probe to 550 to 1000 AU - A Status Review
C. Maccone (2008), JBIS, 61, 310-314Refcode
: Sun gravitational lens, space probe, special relativity, propulsion, telecommunicationsAbstract:
This paper presents a status review of the “FOCAL” space mission studied by this author and others since 1992 and formally proposed to ESA for consideration after the year 2000. The FOCAL probe is intended to reach distances between 550 and 1000 AU to exploit the huge radio magnification provided there by the gravitational lens of the Sun, as predicted by the general theory of relativity. However, the alignment between the radio source (any star, for instance), the centre of the Sun and the FOCAL spacecraft is rather strict, and so it will be necessary to send a FOCAL probe in the opposite sky direction for any stellar system we wish to observe. For instance, before humanity ever embarked in a true interstellar mission even to the closest stars, the Alpha Centauri three stars system at 4.40 light years from us, it plainly appears that before launching a really interstellar spacecraft it will be better to send a FOCAL probe in the opposite direction of the sky. In fact, the distance it must reach is 278 times smaller than 4.40 light-years, or, in other words, assuming equal engineering problems, FOCAL will take 278 times less than the trip to Alpha Centauri. This makes the Sun focus a reasonable target for our probes to reach within this century.
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