An extension of the Voyager primary mission following the flyby of Neptune
by Voyager 2 in 1989. The objective of the VIM
is to extend NASA's exploration of the solar system beyond the neighborhood
of the outer planets to the limits of the heliosphere,
and possibly beyond. Data received from the two Voyagers (and Pioneer
10) into the first decade or two of the twenty-first century will be
used to characterize the outer solar system environment and search for the
heliopause boundary, where the solar
wind meets the interstellar medium. Penetration
of the heliopause by either or both spacecraft, while still active, would
allow the first ever measurements to be made of the interstellar fields
and particles. At the start of the VIM, the two Voyagers had been in flight
for over 12 years. Voyager 1 was at a distance of approximately 40 astronomical
units (6 billion km, or 3.7 billion miles), and Voyager 2 at a distance
of approximately 31 astronomical units (4.7 billion km, or 2.9 billion miles).
Reference
Cesarone, R. J., Sergeyevsky, A. B., and Kerridge, S. Prospects
for the Voyager Interstellar Mission, AAS/AIAA Astrodynamics Specialist
Conference Paper 83-308, Lake Placid, N.Y., Aug. 22-25, 1983.
