Affichage des articles dont le libellé est Mars. Afficher tous les articles
Affichage des articles dont le libellé est Mars. Afficher tous les articles

8.05.2016

CURIOSITY THE MARS ROBOTIC ROVER

Curiosity is a car-sized robotic rover exploring Gale Crater on Mars as part of NASA's Mars Science Laboratory mission (MSL). As of August 5, 2016, Curiosity has been on Mars for 1422 sols (1460 total days) since landing on August 6, 2012.


The Rover Curiosity
 Curiosity was launched from Cape Canaveral on November 26, 2011, at 15:02 UTC aboard the MSL spacecraft and landed on Aeolis Palus in Gale Crater on Mars on August 6, 2012, 05:17 UTC. The Bradbury Landing site was less than 2.4 km (1.5 mi) from the center of the rover's touchdown target after a 563,000,000 km (350,000,000 mi) journey.
The rover's goals include: investigation of the Martian climate and geology; assessment of whether the selected field site inside Gale Crater has ever offered environmental conditions favorable for microbial life, including investigation of the role of water; and planetary habitability studies in preparation for future human exploration.
Curiosity's design will serve as the basis for the planned Mars 2020 rover. In December 2012, Curiosity's two-year mission was extended indefinitely.

Goals and objectives
As established by the Mars Exploration Program, the main scientific goals of the MSL mission are to help determine whether Mars could ever have supported life, as well as determining the role of water, and to study the climate and geology of Mars. The mission will also help prepare for human exploration. To contribute to these goals, MSL has eight main scientific objectives:

Biological

  • Determine the nature and inventory of organic carbon compounds
  • Investigate the chemical building blocks of life (carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur)
  • Identify features that may represent the effects of biological processes (biosignatures and biomolecules)

Geological and geochemical

  • Investigate the chemical, isotopic, and mineralogical composition of the Martian surface and near-surface geological materials
  • Interpret the processes that have formed and modified rocks and soils

Planetary process

  • Assess long-timescale (i.e., 4-billion-year) Martian atmospheric evolution processes
  • Determine present state, distribution, and cycling of water and carbon dioxide

Surface radiation

  • Characterize the broad spectrum of surface radiation, including galactic and cosmic radiation, solar proton events and secondary neutrons. As part of its exploration, it also measured the radiation exposure in the interior of the spacecraft as it traveled to Mars, and it is continuing radiation measurements as it explores the surface of Mars. This data would be important for a future manned mission.

About one year into the surface mission, and having assessed that ancient Mars could have been hospitable to microbial life, the MSL mission objectives evolved to developing predictive models for the preservation process of organic compounds and biomolecules; a branch of paleontology called taphonomy.


Martian rover Curiosity using ChemCam

Specifications
Dimensions: Curiosity has a mass of 899 kg (1,982 lb) including 80 kg (180 lb) of scientific instruments. The rover is 2.9 m (9.5 ft) long by 2.7 m (8.9 ft) wide by 2.2 m (7.2 ft) in height.
Power source: Curiosity is powered by a radioisotope thermoelectric generator (RTG), like the successful Viking 1 and Viking 2 Mars landers in 1976.


Curiosity rover showing the radioisotope thermoelectric generator that supplies electrical power and heat to the rover

Radioisotope power systems (RPSs) are generators that produce electricity from the decay of radioactive isotopes, such as plutonium-238, which is a non-fissile isotope of plutonium. Heat given off by the decay of this isotope is converted into electric voltage by thermocouples, providing constant power during all seasons and through the day and night. Waste heat can be used via pipes to warm systems, freeing electrical power for the operation of the vehicle and instruments. Curiosity's RTG is fueled by 4.8 kg (11 lb) of plutonium-238 dioxide supplied by the U.S. Department of Energy.

Heat rejection system:
The temperatures at the landing site can vary from −127 to 40 °C (−197 to 104 °F); therefore, the thermal system will warm the rover for most of the Martian year. The thermal system will do so in several ways: passively, through the dissipation to internal components; by electrical heaters strategically placed on key components; and by using the rover heat rejection system (HRS). It uses fluid pumped through 60 m (200 ft) of tubing in the rover body so that sensitive components are kept at optimal temperatures. The fluid loop serves the additional purpose of rejecting heat when the rover has become too warm, and it can also gather waste heat from the power source by pumping fluid through two heat exchangers that are mounted alongside the RTG. The HRS also has the ability to cool components if necessary.
Computers: The two identical on-board rover computers, called Rover Computer Element (RCE) contain radiation hardened memory to tolerate the extreme radiation from space and to safeguard against power-off cycles. Each computer's memory includes 256 kB of EEPROM, 256 MB of DRAM, and 2 GB of flash memory. For comparison, the Mars Exploration Rovers used 3 MB of EEPROM, 128 MB of DRAM, and 256 MB of flash memory.


Source : Wikipedia
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8.02.2016

MARS-EARTH COMPARISON TABLE






Mars is only about one-half the diameter of Earth, but both planets have roughly the same amount of dry land surface area. This is because over two-thirds of the Earth's surface is covered by oceans, whereas the present surface of Mars has no liquid water.


Mars and Earth are very different planets when it comes to temperature, size, and atmosphere, but geologic processes on the two planets are surprisingly similar. On Mars, we see volcanoes, canyons, and impact basins much like the ones we see on Earth.






Many of the same physical land features we see on Earth also exist on Mars. But the sheer size of some landforms on Mars dwarfs that of similar features on Earth. The table below compares many of Mars' conditions, specifications and features with those on Earth.








Source : phoenix


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ABOUT THE PLANETE MARS

Travelers of the Future, Beware! Mars is no place for the faint-hearted. Arid, rocky, cold and apparently lifeless, the Red Planet offers few hospitalities. Fans of extreme sports can rejoice, however, for the Red Planet will challenge even the hardiest souls among us. Home to the largest volcano in the solar system, the deepest canyon and crazy weather and temperature patterns, Mars looms as the ultimate lonely planet destination.
If you dream of going, here's what to expect:
Mars Facts:    Learn about the similarities and differences between Mars and Earth, and about the two small moons that orbit Mars.
Mars Earth Comparison:


Earth and Mars comparison


"Mars" here on Earth
If you want to know what it might be like to spend time in the Martian environment, visit the Haughton-Mars Project, which tested prototype Mars astronaut suits on July 26, 2000 and August 3, 2000. The Haughton impact crater is in the Canadian high arctic, and has a rocky polar desert setting somewhat like Mars--though, of course, nothing on Earth comes close to the extreme conditions on the red planet.

Other places on Earth that can help us understand Mars include:

  • Death Valley, California, where Ubehebe crater and "Mars Hill" have geologic features similar to those on Mars
  • Mono Lake, California, which is a 700,000-year-old evaporative lake that compares to Gusev Crater, a basin on Mars where water once was likely
  • Channeled Scabland in Washington, where catastrophic floods swept through the land much like what happened long ago in the Ares Vallis flood plain where Mars Pathfinder landed
  • Permafrost in Siberia, Alaska and Antarctica, where subsurface water-ice and small life forms exist
  • Volcanoes in Hawaii, which are like those on Mars, though much smaller



Source : NASA 

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8.01.2016

MARS THE MESTERIOUS RED PLANETE

Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, after Mercury. Named after the Roman god of war, it is often referred to as the "Red Planet" because the iron oxide prevalent on its surface gives it a reddish appearance. Mars is a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the valleys, deserts, and polar ice caps of Earth.



The rotational period and seasonal cycles of Mars are likewise similar to those of Earth, as is the tilt that produces the seasons. Mars is the site of Olympus Mons, the largest volcano and second-highest known mountain in the Solar System, and of Valles Marineris, one of the largest canyons in the Solar System. The smooth Borealis basin in the northern hemisphere covers 40% of the planet and may be a giant impact feature. Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to 5261 Eureka, a Mars trojan.



Until the first successful Mars flyby in 1965 by Mariner 4, many speculated about the presence of liquid water on the planet's surface. This was based on observed periodic variations in light and dark patches, particularly in the polar latitudes, which appeared to be seas and continents; long, dark striations were interpreted by some as irrigation channels for liquid water. These straight line features were later explained as optical illusions, though geological evidence gathered by uncrewed missions suggests that Mars once had large-scale water coverage on its surface at an earlier stage of its existence. In 2005, radar data revealed the presence of large quantities of water ice at the poles and at mid-latitudes. The Mars rover Spirit sampled chemical compounds containing water molecules in March 2007. The Phoenix lander directly sampled water ice in shallow Martian soil on July 31, 2008. On September 28, 2015, NASA announced the presence of briny flowing salt water on the Martian surface.



Mars is host to seven functioning spacecraft: five in orbit 2001 Mars Odyssey, Mars Express, Mars Reconnaissance Orbiter, MAVEN and Mars Orbiter Mission and two on the surface Mars Exploration Rover Opportunity and the Mars Science Laboratory Curiosity. Observations by the Mars Reconnaissance Orbiter have revealed possible flowing water during the warmest months on Mars. In 2013, NASA's Curiosity rover discovered that Mars's soil contains between 1.5% and 3% water by mass (albeit attached to other compounds and thus not freely accessible).



There are ongoing investigations assessing the past habitability potential of Mars, as well as the possibility of extant life. In situ investigations have been performed by the Viking landers, Spirit and Opportunity rovers, Phoenix lander, and Curiosity rover. Future astrobiology missions are planned, including the Mars 2020 and ExoMars rovers.
Mars can easily be seen from Earth with the naked eye, as can its reddish coloring. Its apparent magnitude reaches −2.91, which is surpassed only by Jupiter, Venus, the Moon, and the Sun. Optical ground-based telescopes are typically limited to resolving features about 300 kilometers (190 mi) across when Earth and Mars are closest because of Earth's atmosphere.

Source : Wikipedia





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