Mars (2)
Mars as seen from the Hubble telescope.
Diameter 6,794 km
4,220 mi.
Distance from the Sun 228 million km
141 million mi.
Astronomical Unit 1.5
Mass 6.4185×10^23 kg

0.107 Earths

Density 3.9335±0.0004 g/cm³
Nickname(s) Red Planet
The Fourth Rock
Valley World
Earth's Neighbor
Dusty Planet
Harbor Planet
Liquid Water World
Number of moons 2
Length of day 24 hours
Length of year 687 days
Atmosphere Components Carbon (dioxide)
Symbol Mars symbol

Mars is the fourth planet from the Sun and it is the seventh largest planet in the solar system. Its axial inclination is similar, giving it seasons like Earth. Polar ice caps expand and recede. Mars has less gravity and atmosphere with similar cloud types. Its dormant volcanoes are the largest in our solar system. Mars has two moons, Phobos and Deimos.[1]

For a planet to have liquid water, it must be the perfect distance from the Sun, not so close that it boils away, and not so far that it freezes.

There is no liquid water on Mars, it is generally far too cold and the atmospheric pressure is too low. While there are certain places (near the equator) on Mars that occasionally reach temperatures high enough for liquid water to exist, the atmospheric pressure is so low that any ice on the ground surface would change directly from ice into vapor, which is called sublimation.

Roman God of WarEdit

Roman God Of War

A war.

Mars was the son of Juno and a magical herb, the Roman god of war. Mars was also the father of Romulus and Remus, the founders of Rome. For this reason, Mars was one of the most widely worshiped gods among the Roman people.


Valles Marineris

This picture shows the Valles Marineris was taken from the Viking spacecraft.

The largest canyon in the Solar System cuts a wide swath across the face of Mars. Named Valles Marineris, the grand valley extends over 3,000 kilometers long, spans as much as 600 kilometers across, and delves as much as 8 kilometers deep. By comparison, the Earth's Grand Canyon in Arizona, USA is 800 kilometers long, 30 kilometers across, and 1.8 kilometers deep. The origin of the Valles Marineris remains unknown, although a leading hypothesis holds that it started as a crack billions of years ago as the planet cooled. Recently, several geologic processes have been identified in the canyon.[2][3][4][5][6]

Largest VolcanoEdit

Olympus Mons

An Olympus Mons was taken from the Viking spacecraft.

The largest volcano in the Solar System is on Mars. Olympus Mons rises 24 kilometers high and measures 550 km across. By comparison, Earth's largest volcano, Mauna Loa in Hawaii, rises 9 km high and measures 120 km across. Such large volcanoes can exist on Mars because of the low gravity and lack of surface tectonic motion. Olympus Mons is a shield volcano, built by fluid lava.[7]

Life on Mars?Edit

For centuries people have speculated about the possibility of life on Mars owing to the planet's proximity and similarity to Earth. Serious searches for evidence of life began in the 19th century, and continue via telescopic investigations and landed missions. While early work focused on phenomenology and bordered on fantasy, modern scientific inquiry has emphasized the search for chemical biosignatures of life in the soil and rocks at the planet's surface, and the search for biomarker gases in the atmosphere. Fictional Martians have been a recurring feature of popular entertainment of the 20th and 21st centuries, and it remains an open question whether life currently exists on Mars, or has existed there in the past.



Artist's concept of Phoenix.

The Phoenix Mission inherits a highly capable spacecraft partially built for the Mars Surveyor Program 2001 and important lessons learned from the Mars Polar Lander. The spacecraft was in an advanced state of development when NASA canceled Mars Surveyor 2001 and has been housed in a Class 100,000 clean high-bay facility at Lockheed Martin Space Systems, Littleton, Colorado.

The spacecraft will experience extreme conditions during travel to and exploration of Mars. During launch, the spacecraft will undergo tremendous load forces and shaking stresses as the launch vehicle is propelled out of Earth's gravity well. During the 10-month cruise to Mars, the spacecraft must be able to withstand the vacuum of space with potential radiation hazards from solar storms and micro-meteor impacts from interplanetary dust. During entry, descent, and landing, the spacecraft will be heated to thousands of degrees during aeroshell braking, jerked with tremendous force as the parachute is deployed, and finally will come to a soft touchdown using controlled thrusters. Finally, during surface operations, the spacecraft must withstand the extremely cold temperatures of the martian arctic and the dust storms that potentially affect the area.

Designing and constructing a spacecraft to withstand these extremes is a tricky endeavor and requires considerable testing before launch. Benefiting from the lessons learned during the Mars Polar Lander and Mars Surveyor Program 2001 experience, as well as further reliability upgrades and subsystems used in previous successful space missions, the spacecraft is in a high state of development early in the mission's fabrication phase. Therefore, the mission engineering team is working on developing enhanced spacecraft reliability through extensive testing, (i.e., beyond normal integration and environment testing that occurs for most missions).

The spacecraft has several subsystems that are being updated, if necessary, with parts and software that will increase reliability. These subsystems include (1) command and data handling, controlling the spacecraft's computer processing, (2) electrical power, consisting of solar panels, batteries, and associated converting circuits, (3) telecommunications, ensuring flow of data to and from Earth, (4) guidance, navigation, and control, assuring the spacecraft arrives safely at Mars, (5) propulsion, controlling trajectory correction maneuvers during cruise and thrusters during landing, (6) structure, providing the spacecraft framework and integrity, (7) mechanisms, enabling the movement of several spacecraft components, and (8) thermal-control, using heat transfer to ensure proper temperature ranges on all parts of the spacecraft.

How to find a soil?Edit

The fact that NASA's Phoenix lander spotted perchlorate near the Martian north pole in 2008 presented another reason to believe life could be possible on this planet. Previous landers would vaporize Martian soil and look for any organics boiling off, but they only found a few chlorine compounds (which were attributed to contamination). After the perchlorate discovery, scientists added perchlorate to some desert dirt from Chile known to contain organics, heated the soil up and found the same chlorine compounds found in Mars. This suggests that organics may have been present in the Martian soil but were broken down by the combination of heat and perchlorate.[8]

Viking to MarsEdit

Barsoom from Viking 2

This dramatic picture of a crescent Mars was taken by NASA's Viking 2 spacecraft as it approached Barsoom in 1976.

The Viking Project began in 1968 when the race for the Moon was in high gear, but its twin spacecraft did not arrive at the launch pad until 1975. A sagging U.S. economy and an expensive Vietnam War forced the government to cut deeply into NASA's budget. While the Viking mission was put on hold, the Soviet Union eagerly snapped up the 1973 launch opportunity with four probes. The race to put a successful lander on Mars looked like an easy win for the USSR. But it was Viking that was destined to take that honor as well as the distinction of being one of the most elaborate missions in the history of Martian exploration.