== Interstellar Age ==
Jim Bell, Penguin/Dutton 2015, Tigard Library 629.43 BEL
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 .p46 Bell claims 1965, Caltech Gary Flandro invented "Grand Tour", little credit until 1998 NASA Exceptional Achievement Medal. 
  .probably not accurate
  .Kohlhase p104: 1961, gravity assist invented by 25 yo Michael A. Minovitch, mathematician grad student at JPL, 1962, Grand Tour
  .1964 Max Hunter writes about it, 1965 Flandro works out details.
  .Flandro: ''You have to learn not to be discouraged by experts''
 .p68 11,000 work-years devoted to Voyager, 1/3 of the labor force for the Great Pyramid at Giza for King Cheops
  . cite: C. Kohlhase ''The Voyager Neptume Travel Guide'', [[ http://babel.hathitrust.org/cgi/pt?id=uiug.30112056430637 | JPL Publication 89-24 ]] [[http://hdl.handle.net/2060/19900004096 | NASA ntrs]] page 135 
   .Kohlhase: $865M, 5 trillion bits, Deep space network antenna captures 1e-16 W
 .p81 re. Voyager disks, Hawking said we are simply not evolved enough to make contact.  
  .Analogies to aboriginal contacts invalid;  most damage was disease, we have science and can figure things out, contact will be very slow.
 .p146 Enceladus pronounced en-CELL-uh-dus

After the last planetary encounter (Voyager 2 passed Neptune in 1989), the spacecraft cameras were shut down, though sensors remain active, and may continue to work until 2025 or so, when the RTG power sources decay and cannot provide enough power to keep the electronics warm.   

The termination shock was traversed by Voyager 1 in 2004, and Voyager 2 in 2007.  

The heliosheath is 80 to 100 AU out.

Voyager 1's plasma density instrument failed at Saturn, but other instruments (probably) detected the edge of the heliopause on August 25, 2012.   Ed Stone is the project leader for keeping this $5M/year program alive.  Current distance is about 133 AU (2015 September).

Voyager 2 is leaving the sun at 15.4 km/s, 3.26 AU per year, and was 108 AU away (2015 April), crossing the heliopause Real Soon Now.