Mars is the fourth planet from the sun at 227,940,000 km.
It is also known as the red planet because of the pinkish
coloured dust in it's atmosphere. Mars is the seventh largest planet and has
two small satellites (moons) that orbit close to its surface, Phobos and Deimos.
Phobos, the largest of the two moons,
orbits about
6000 km away.
Deimos, the smallest known moon in the solar system,
orbits about 23 000 km away.
Both Mars' two moons were discovered by
Asaph Hall ( 1829-1907) in 1877.
The first spacecraft to visit Mars wasMariner 4 in 1965,
which took the first close up images of the planets surface.
It was launched on Nov 28 1964 and reached Mars on
July 4 1965.It took 22 pictures in all.
There have been several missions to date
including Mariner 9, the sister probe to
Mariner 8 which failed on launch.
Mariner 9 was launched on May 30 1971.
It became the first probe to orbit Mars and took the first detailed images
of Phobos and Deimos.
In 1971 the Russian Mars 2 became the first spacecraft to land on the planets
surface.
There is clear evidence of some form of liquid errosion (possibly water) on the surface of Mars, including
large flooded areas and small rivers.It seems this was only a brief period in the planets history some
4 billion years ago. Mars has ice caps at both poles, made mostly of solid carbon dioxide (dry ice).
It stands 24 km (78 000 ft) high, has a base 500 km in diameter and is circled by a cliff 6 km (20 000 ft) high.
The Mars Pathfinder was launched on Dec 4 1996 and made a successful landing
on July 4 1997.
Mars Pathfinder consisted of a stationary lander and a surface rover called
Sojourner.
