Hydranencephaly or hydrancephaly [1] is a condition in which the brain's cerebral hemispheres are absent to varying degrees and the remaining cranial cavity is filled with cerebrospinal fluid.[2]
JPL built and operates the twin Voyager spacecraft. The Voyagers Interstellar Mission is a part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of NASA's Science Mission Directorate in Washington.
The probe was moving at a velocity of 15.4 km/s (55,000 km/h) relative to the Sun as of December 2014 and is traveling through the heliosheath. Upon reaching interstellar space, Voyager 2 is expected to provide the first direct measurements of the density and temperature of the interstellar plasma.