Mars Facts
the red planet
Mars, aptly nicknamed the Red Planet.
Planet Mars Facts
  • Mars is the fourth planet from the sun, its diameter is only around 4,200 miles (6800 km) which is half the size of Earth.
  • It travels around the sun every 687 days and rotates on its own axis every 24 hours 40 minutes.
  • The average distance from Mars to the sun is around 142 million miles (228 million km), one and half times further away from the sun than our planet.
  • The distance between Mars and Earth varies, from as little as 34 million miles (55 million km) to as much as 249 million miles (401 million km).
  • There are vast amounts of water ice under the Martian surface.
  • Evidence shows that water used to flow on the surface of Mars.
  • Mars has seasons just like Earth.
  • Gravity on Mars is around two fifths of that on Earth.
  • Clouds made from frozen CO2 form in the Martian sky. Haze and fog are also common.
  • Dust storms on Mars can last for months and cover the entire planet.

mars surface
Image of the Martian surface captured by NASA's Pathfinder Lander.
mars sunset
A Martian dust devil captured by NASA's Rover Spirit.

Mars Surface
Mars has similar surface features that exist on Earth such as flat plains and sloping hills giving it a rather familiar look. Unlike Earth craters are present all over the planet showing a lack of any major geological activity for possibly billions of years. Evidence of past water are etched out on the planet's surface in the form of huge canyons and river valleys giving us a glimpse of how different the planet may have looked in the distant past. Mars also has huge extinct volcanoes, the largest of which is three times higher than Mount Everest. The planet gets its reddish color from the presence of iron-oxide, otherwise known as rust.
Mars has polar caps primarily composed of water ice but covered in a layer of frozen carbon dioxide. In the warmer periods of its year the carbon dioxide evaporates in the northern pole revealing the frozen water below.
Mars Temperature
Surface temperatures on Mars vary from as low as -125C (-195F) near the poles to around 20C (68F) at midday near the equator. The highest recorded air temperature on Mars is 35C (95F).
Mars Atmosphere
The thin atmosphere of Mars is only around 1% the density of our own atmosphere, consisting of 95% carbon dioxide. With atmosphere comes weather, strong winds can produce massive dust storms, dust devils are created by warm daylight air rising from the surface, faint clouds form in the Martian sky and even snow falls in the form of frozen carbon dioxide.

Moons
Mars has two very small moons, Phobos which has a diameter of 17 km (28 km) and Deimos which has a diameter of 9 miles (15 km). It is probable that they were once asteroids that were caught by the gravity of the planet.
Life on Mars
Mars may once have harbored life and may still do today. Most likely life could exist in warm pockets beneath the ground, methane has been detected in the Martian atmosphere which could have been produced biologically. In the summer months the amount of methane increases dramatically giving further credence to this theory.
Origin of Name
Mars is named after the Roman God of War.

Colonizing Mars

mars domes
A future Mars colony using inter connecting domes
When considering planets in the solar system that mankind can colonize there really only is one candidate. The two rocky planets close to the sun, Venus and Mercury, are baking hot infernos and the gas giants such as Jupiter and Saturn have no solid surface. So that leaves us with Mars, even though it is extremely inhospitable to humans in most respects it is by far the most Earth like when compared to the other planets of our solar system.

The red planet has many qualities that make it attractive to prospective colonizers such as its closeness to Earth, the familiarity of a 24 hour day or the fact that Mars has seasons just like on Earth. Undoubtedly though the most important quality is the abundance of water on Mars. Underneath its surface lies a thick layer of water ice, apart from its obvious uses such as drinking, cooking and hygiene, water can also be used for energy, such as rocket fuel by separating the hydrogen and oxygen.

Bases could be built on Mars in the form of interconnecting reinforced domes which allow for the largest space with the least amount of materials. Colonies would eventually become completely self sufficient, growing their own food, perhaps hydroponically, without the need for soil. Mars could also be used as a base for mining the incredible mineral wealth of the asteroid belt, the iron taken from there could be used to build more structures on the surface without the need of supplies from Earth, which could see colonies rapidly grow.

Of course there are many hazards on Mars, the thin atmosphere gives little protection from the suns rays so radiation levels are very high. Temperatures even in the warmest areas of Mars can dip below -60C (-80F) and there are frequent massive dust storms, you don’t want to be going for a walk on Mars unless you are very well protected. Another factor that needs to be taken into account is that gravity on Mars is only around two fifths of what we experience on Earth, this may not be enough to stop our bones and muscles from deteriorating, daily exercise may have to be part of a colonizers routine.

Even with all the dangers Mars poses there would be no shortage of volunteers to become 21st century pioneers. Many will not be able to resist the lure of visiting an alien planet, witnessing a red sky or visiting the breathtaking canyons and volcanoes that exist on Mars.

Missions to Mars
ExoMars
exomars rover Launch: 2018
Agency: ESA (Europe)
Summary: The ExoMars rover will be designed to search for life on Mars.
Maven
maven Launch: November 2013
Arrival: September 2014
Agency: NASA
Summary: The Mars Atmosphere and Volatile Evolution Mission will address key questions about previous, current and future conditions on Mars.
Mars Science Laboratory (MSL)
mars curiosity rover Launch: November 2011
Arrival: August 2012
Agency: NASA
Summary: MSL, also known as the Mars Curiosity Rover, is the next generation of Mars rovers. A rocket and cable assisted descent mechanism was used in order to land the rover in more rugged terrain. It is currently exploring the Martian surface, conducting experiments on rocks and soil using its wide variety of advanced instrumentation.
Phoenix
phoenix Launch: August 2007
Arrival: May 2008
Agency: NASA
Summary: Landed near Mars north pole to study the water ice found there and locate any possible habitable environments. The Pheonix lander sent back data over a period of 6 months, confirming the presence of water ice under the Martian surface.
Mars Reconnaissance Orbiter
mars reconnaissance orbiter Launch: August 2005
Arrival: March 2006
Agency: NASA
Summary: MRO is searching for evidence of past water on Mars and also looking for future landing sites. It will also act as a communications relay for future missions.
Mars Exploration Rover Opportunity
mars exploration rover opportunity Launch: July 2003
Arrival: January 2004
Agency: NASA
Summary: Opportunity is still roving across the Martian landscape finding abundant evidence for the action of liquid water. It has survived many times longer than planned.
Mars Exploration Rover Spirit
mars exploration rover spirit Launch: June 2003
Arrival: January 2004
Agency: NASA
Summary: Spirit had to rove several kilometers before it found evidence of past water. It also explored ancient Mars rocks preserved in mountains. Rover Spirit survived on the Maritan surface for six years, many times longer than originally planned.
Mars Express
mars express Launch: June 2003
Arrival: December 2003
Agency: ESA (Europe)
Summary: As it entered orbit Mars Express immediately began returning stunning 3D color images. It also detected surprising levels of methane and evidence for recent volcanic activity. Unfortunately the lander it carried, Beagle 2, apparently crashed into the Mars surface.
Mars Odyssey
mars odyssey Launch: April 2001
Arrival: October 2001
Agency: NASA
Summary: Mars Odyssey is capturing images of the Martian surface and has detected massive deposits of water under the near polar regions. It also serves as a communications relay for the rovers.
Mars Pathfinder & Sojourner
pathfinder Launch: December 1996
Arrival: July 1997
Agency: NASA
Summary: Successfully landed on the Mars surface, the six wheel rover Sojourner also successfully rolled of the ramp onto land returning images and weather data. The mission scheduled to last 30 days lasted almost 3 months.
Mars Global Surveyor
global surveyor Launch: November 1996
Arrival: September 1997
Agency: NASA
Summary: Initially had problems on its arrival due to an issue with one of its solar panels. It wasn't until a year and a half later that it started returning a wealth of data and high resolution images. Contact was lost in November 2006.
Viking 2
viking lander Launch: September 1975
Arrival: August 1976
Agency: NASA
Summary: The Viking 2 lander successfully touched down on the planet taking extensive atmospheric readings and conducting experiments on soil samples. The lander functioned for 4 years observing several winters which covered it in an extremely thin layer of frost. The orbiter was shut down in July 1978. Between them the two landers had taken 1,400 images of the Martian surface and the orbiters 50,000 images creating a global map which is still used today.
Viking 1
viking 1 Launch: August 1975
Arrival: June 1976
Agency: NASA
Summary: Entered Mars orbit and immediately began searching for a safe landing site for the lander. The lander successfully touched down on the Mars surface taking extensive weather readings and conducting experiments on soil samples collected with a scoop. The orbiter was powered down in August 1980. The lander survived until November 1982.
Mars 4,5,6 and 7
mars 4 Launch: July - August 1973
Arrival: February - March 1974
Agency: Soviet Union
Summary: Mars 4,5,6 and 7 were rushed forward by the Soviets in an attempt to get a craft on the Martian surface before the United States. As a result they were mostly unsuccessful. Even so they did still manage to send back some data before their quick demise including taking images and gathering data on the atmosphere. Notably Mars 6 did manage to launch a lander into the Martian atmosphere which broadcast data for almost 4 minutes before abruptly cutting off.
Mars 2 and 3
mars 3 Launch: May 1971
Arrival: November - December 1971
Agency: Soviet Union
Summary: Mars 2 and 3 had the misfortune to arrive at Mars during one of the worst dust storms ever recorded there. Even so one of their landers managed to touch down briefly on the planet's surface before being apparently blown over after only 20 seconds. The orbiters were somewhat more successful returning images, recording temperatures and studying the Martian atmosphere.
Mariner 9
mariner 9 Launch: May 1971
Arrival: November 1971
Agency: NASA
Summary: The first spacecraft to go into orbit around another planet. It had to wait a month and a half to begin its mission as a dust storm had covered the entire planet. Afterwards though it sent back a whole raft of data including over 7,000 images of Mars, the atmospheric and surface composition, density and pressure of its atmosphere, also details about the planet's gravity and topography. On top of that it also sent back the first close up images of the two moons of Mars, Phobos and Deimos.
Mariner 6 and 7
mariner 6 Launch: February - March 1969
Arrival: July - August 1969
Agency: NASA
Summary: Mariner 6 and 7 successfully flew by Mars collecting data on the mass, radius, the shape of Mars and the composition of its southern ice cap. Between them they took 200 images.
Mariner 4
mariner 4 Launch: November 1964
Arrival: July 1965
Agency: NASA
Summary: The first spacecraft to fly past Mars taking close up images of the planet. It also confirmed the existence of a thin atmosphere consisting mainly of carbon dioxide.

mars sunset
Spectacular image of a Martian sunset taken by NASA's rover Spirit.
Planet Mars Statistics

Diameter: 4,212 miles (6,779 km)
Average Distance from Sun: 142 million miles (228 million km)
Orbital Period: 687 days
Rotation Period: 24.62 hours

Maximum Surface Temperatures: 20C (68F)
Minimum Surface Temperatures: -125C (-195F)

Gravity: 3.693 m/s2 (38% Earth's Gravity)
Density: 3.94 g/cm3 (71.4% Earth's Density)
Mass: 6.4185 x 1023 kg (10.7% Earth's Mass)
Volume: 1.6314 x 1011 km3 (15% Earth's Volume)

Atmosphere: 95.32% carbon dioxide, 2.7% nitrogen, 1.6% argon, 0.13% oxygen, 0.08% carbon monoxide.

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