The identical pair of spacecraft were laden with instruments
to enable them to conduct 10 different experiments. Equipment
included cameras, magnetic field detectors, and a 12 ft high
antenna providing communication between the spacecraft and
the controllers on earth (Deep Space Network).
Voyager I & 2 were launched by NASA in the summer of 1977
from Cape Canaveral, Florida. Voyager 1 was set on a shorter
faster route reaching Jupiter (400 million miles away) in
18 months.
Major Discoveries Voyager images show the swirling violent
atmosphere of Jupiter in amazing detail. In 1979 they reported
a giant storm 3 times the size of the earth surrounded by
heaving rotating currents and cloud top lightning bolts. The
data proved vital in understanding the atmospheric processes
on Jupiter that could never have been accurately studied from
earth. Vast scales of temperature were recorded from -112ºC
(170ºF) in the atmosphere to 830ºC (1500ºF) in the ionosphere.
The Great Red Spot was revealed to be a complex storm moving
in an anticlockwise direction with the outer edge rotating
over 4-6 days.
The greatest and most unexpected discovery of Voyager was
that for the first time ever, active volcanoes were seen on
another body in the solar system. Startling photographs show
Plumes that reached 190 miles from the surface. Experiments
found that material was being ejected at 2,300 miles an hour.
(In comparison Mount Etna explodes at 112 miles an hour).
Voyager I discovered 9 active volcanoes erupting on Io, the
innermost of Jupiter's four major moons and four months later
Voyager 2 found that eight of the nine were still erupting.
The volcanoes are considered to be a result of Io being heated
as it is pulled toward Jupiter. Europa and Ganymede also affect
Io's orbit but as Jupiter pulls it back tidal bulging occurs
of up to 330 feet (compared to 3 feet on earth) and Io is
tugged by Jupiter's huge gravitational force. Oxygen, sodium
and sulphur from these volcanoes was detected in the edges
of Jupiter's magnetosphere concluding that the activity on
Io affects the whole of Jupiter's planetary system.
The existence of a magnetail was also confirmed which reached
400 million miles to Saturn. A thin dusty ring was also discovered
around Jupiter with an outer edge 80,000 miles from its centre
but only 20 miles thick. The ring was considered to consist
of material from major moons. Voyager also observed auroras
similar to the Northern Lights in Jupiter's Polar regions
which also related to material from Io.
As a result of the Voyager missions a number of new were
discovered around Jupiter, including Adrastea (25 miles diameter)
and Thebe (50). Ganymede was proved to be the largest satellite
in the solar system and not Saturn's Titan as was previously
thought.
