Kohlhase meets legendary astronomer, Clyde Tombaugh, discoverer of Pluto,
at the Voyager Neptune encounter in August 1989. Credit: Charles Kohlhase
RS: For how long were you involved with Voyager?
KOHLHASE: “Most of my intense work was from 1974 until
launch in 1977, designing all the options for the missions.”
RS: You had to balance the interests of engineers
and scientists. That must have been a difficult job,
trying to satisfy the requirements of both groups?
KOHLHASE: “There were certain
engineering constraints we felt
pretty strongly about. We could
lay those out in the launch datearrival date space and make sure
we avoided, say, flying behind
one of the planets and looking
back at the Sun if the Earth was
in the same direction. There
were many things to consider.
“I think the most interesting
issue we had to deal with was
the sheer number of trajectory
possibilities. There were some
10,000 of these, taking into account
the orbital periods of Jupiter and
Saturn and those of their dozens of satellites. The trick
was to find the best encounter dates at each planet
that gave you the largest number of close encounters
with bodies of interest. We also had three different
launch opportunities in 1976, ‘77 and ’78. 1977 was the
‘Goldilocks’ opportunity, with the arrangement perfect
for flying through the region of the Galilean satellites.
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