FOCAL (spacecraft)

FOCAL (an acronym for Fast Outgoing Cyclopean Astronomical Lens) is a proposed space telescope that would use the Sun as a gravity lens. The gravitational lens effect was first derived by Albert Einstein,[1] and the concept of a mission to the solar gravitational lens was first suggested by professor Von Eshleman,[2] and analyzed further by Italian astronomer Claudio Maccone[3] and others.[4]

In order to use the Sun as a gravity lens, it would be necessary to send the telescope to a minimum distance of 550 astronomical units away from the Sun,[3]: 4–7  enabling very high signal amplifications: for example, at the 203 GHz wavelength, amplification of 1.3·1015.[5] Maccone suggests that this should be enough to obtain detailed images of the surfaces of extrasolar planets.[6]

  1. ^ Einstein, Albert (1936). "Lens-Like Action of a Star by the Deviation of Light in the Gravitational Field". Science. 84 (2188): 506–507. Bibcode:1936Sci....84..506E. doi:10.1126/science.84.2188.506. PMID 17769014.
  2. ^ Eshleman, V. R. (1979). "Gravitational Lens of the Sun: Its Potential for Observations and Communications over Interstellar Distances". Science. 205 (4411): 1133–1135. Bibcode:1979Sci...205.1133E. doi:10.1126/science.205.4411.1133. ISSN 0036-8075. PMID 17735051. S2CID 27692082.
  3. ^ a b Maccone, Claudio (2009-06-09). Deep Space Flight and Communications: Exploiting the Sun as a Gravitational Lens. Berlin: Springer Science & Business Media. ISBN 9783540729426. Retrieved 2015-01-18.
  4. ^ Turyshev, S. G. and Andersson, B-G., “The 550-AU Mission: a critical discussion”, Mon. Not. R. Astron. Soc. 341, pp. 577–582 (2003).
  5. ^ Chorost, Michael (2013-06-26). "The Seventy-Billion-Mile Telescope". The New Yorker.
  6. ^ Villard, Ray (2011-01-10). "Using The Sun as a Magnifying Glass". Archived from the original on 2014-05-19.