Mars [1] named
after the Roman god of war and sometimes referred to as the "Red
Planet" orbits the Sun at a
distance of
227,940,000 kilometers or 1.52 AU (1 AU being
the distance
between the Sun
and the Earth, approximately 150,000,000
kilometers.) placing it just inside or at the outer periphery of
the
Solar
System’s habitable zone, [2] while a mean diameter of 6,794 kilometers
makes it the seventh largest of the planets in size.
A
great many spacecraft have
visited Mars beginning with Mariner 4 in 1965, but on July 4, 1997, a
milestone
in human exploration became reality when the Mars Pathfinder
successfully landed in Ares Vallis, opened, and allowed a mobile rover
called Sojourner to begin examining the surrounding terrain. This was
followed by the Mars Expedition rovers,
Spirit and Opportunity, which were successfully delivered to the
planet’s
surface and began controlled exploration in 2004.
On May 25, 2008, these were followed in turn by the Phoenix lander a
static device (equipped with a robotic digging arm) designed to search
for enviorments suitable for microbial life and confirm the presence of subsurface water ice. Armed
with high resolution cameras, spectrometers and other scientific
equipment these solar powered robots are sending back
invaluable information and incredible pictures. This information along
with that being gathered by the orbiters Mars Express,
Mars
Reconnaissance Orbiter and Mars Odyssey is part of an
ongoing process which slowly but surely is uncovering Mars'
secrets. [3]
The
search for water
both on and below the surface is a high priority. Its presence in
significant amounts is of paramount importance to future human
exploration and eventual colonization of the planet. In fact a vast
frozen sea has been discovered in Mars’ Elysium region, covered in dust
and
other detritus it appears
to be
less than five million years old.