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Astronomy and Space articles
by Martin George of the Launceston Planetarium
14 July 2012
Three Years To Pluto
It's three years from today that the New Horizons craft, enroute to Pluto, will fly past that
dwarf planet and give us our first-ever close look at an object that has been the subject of
so much attention for the past 82 years.
New Horizons was launched in early 2006, and so has been travelling for six and a half
years now. It is past the orbit of Uranus, and will become only the fifth craft to leave the
realm of the planets and continue on to interstellar space.
An artist's impression of the the New Horizons craft passing Pluto in 2015. Credit: NASA
Astronomy and Space articles
by Martin George of the Launceston Planetarium
14 July 2012
The other craft that have done this are Pioneers 10 and 11, and Voyagers 1 and 2, which
investigated the planets in the outer solar system in the 1970s and 1980s. The Voyagers
are still transmitting information about the conditions way out beyond Pluto, but did not go
anywhere close to Pluto itself.
As happened during those planetary encounters, New Horizons will not enter orbit around
its target. It will simply perform a flyby, with the most critical period being in mid-July
when it will pass within about 14,000 kilometres of Pluto. Pluto's diameter is abut 2,300
kilometres, so this means that the craft will pass only about five and a half 'Pluto
diameters' from the surface.
As seen from the spacecraft, Pluto will, at that stage, appear about the same apparent
size as a fist held at arm's length, or about 20 times the apparent diameter of the Moon
as seen from Earth.
New Horizons is continuing to head toward Pluto at a speed of about 15.24 kilometres
per second, and is currently 3.55 billion kilometres from the Sun. At that speed, it would
make the journey along the Midland Highway from Hobart to Launceston in a little over 13
seconds!
New Horizons was 'woken up' on 30 April after a period of hibernation, and in the ensuing
weeks many tests were performed to ensure that all of its systems were working properly.
Included were a number of software upgrades to fix 'bugs' in the system, but all appears
to be well.
The next major milestone for New Horizons will be reached on 24 August 2014, when it
crosses the orbit of Neptune, now the most distant planet from the Sun after Pluto's
demotion to 'dwarf planet' status in 2006.
Serious observation of Pluto will begin in February 2015, as by that time, the craft will be
close enough to Pluto to do some real science. By May of that year, the images taken by
the craft will be as good as the best that have been taken by the Hubble Space
Telescope, which is in orbit around the Earth.
We hope to learn a lot about Pluto from this intrepid spacecraft. It will be an exciting time,
although we shall have to wait for a while to obtain all the data from the encounter. A
great deal of data will be gathered during the flyby, but at the great distance of Pluto, the
rate at which the data is returned will be quite low!
Article by Martin George, Launceston Planetarium, QVMAG.
Reproduced with permission of the Mercury newspaper.