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On the morning of Friday 20th
January 2006, the Canberra
Deep Space Communication Complex
supported the first leg of the New Horizons spacecraft's long
journey to Pluto, due to arrive at 9.58:59, 15th July, 2015.
New Horizons is designed to
help us understand worlds at the edge of our solar system by
making the first reconnaissance of Pluto and Charon - a "double
planet" and the last planet in our solar system to be visited
by spacecraft. Then, as part of an extended mission, New Horizons
would visit one or more objects in the Kuiper Belt region beyond
Neptune.
Science
at the Frontier
Our solar system contains three zones: the inner, rocky planets;
the gas giant planets; and the Kuiper Belt. Pluto is the largest
body of the icy, "third zone" of our solar system.
The National Academy of Sciences placed the exploration of the
third zone in general - and Pluto-Charon in particular - among
its highest priority planetary mission rankings for this decade.
New Horizons is NASA's mission to fulfil this objective.
In those zones, our solar system
has three classes of planets: the rocky worlds (Earth, Venus,
Mercury and Mars); the gas giants (Jupiter, Saturn, Uranus and
Neptune); and the ice dwarfs of the Kuiper Belt. There are far
more ice dwarf planets than rocky and gas giant worlds combined
- yet, no spacecraft has been sent to a planet in this class.
The National Academy of Sciences noted that our knowledge of
planetary types is therefore seriously incomplete. As the first
mission to investigate this new class of planetary bodies, New
Horizons seeks to fill this important gap and round out our knowledge
of the planets in our solar system.
Ancient
Relics
The ice dwarfs are planetary embryos, whose growth stopped at
sizes (200 to 2,000 kilometres across) much smaller than the
full-grown planets in the inner solar system and the gas giants
region. The ice dwarfs are ancient relics that formed over 4
billion years ago. Because they are literally the bodies out
of which the larger planets accumulated, the ice dwarfs have
a great deal to teach us about planetary formation. New Horizons
seeks those answers.
Binary Planet
Pluto's moon, Charon, is half the size of Pluto. The pair form
a binary-planet, whose gravitational balance point is between
the two bodies. Although binary planets are thought to be common
in the galaxy, as are binary stars, no spacecraft has yet explored
one. New Horizons will be the first mission to a binary object
of any type.
A Mission
with Impact
The Kuiper Belt is the major source of cometary impactors on
Earth, like the impactor that wiped out the dinosaurs. New Horizons
will shed new light on the number of such Kuiper Belt impactors
as a function of their size by cataloguing the various-sized
craters on Pluto, Charon, and on Kuiper Belt Objects.
Pluto and the Kuiper Belt are
known to be heavily endowed with organic (carbon-bearing) molecules
and water ice the raw materials out of which life evolves.
New Horizons will explore the composition of this material on
the surfaces of Pluto, Charon and Kuiper Belt Objects.
The Great
Escape
Pluto's atmosphere is escaping to space like a comet, but on
a planetary scale. Nothing like this exists anywhere else in
the solar system. It is thought that the Earth's original hydrogen/helium
atmosphere was lost to space this way. By studying Pluto's atmospheric
escape, we can learn a great deal about the evolution of Earth's
atmosphere. New Horizons will determine Pluto's atmospheric structure
and composition and directly measure its escape rate for the
first time.
As the first voyage to a whole
new class of planets in the farthest zone of the solar system,
New Horizons is a historic mission of exploration and completes
the first stage of the reconnaissance of the Solar System.
Article compiled from the
New Horizons website |