NASA's "Curiosity" rover lands at the foot of a tall mountain rising from the Gale Crater in the Martian southern hemisphere. There are plans for a two year research effort on Mars. A rocket-powered sky crane lowered "Curiosity" to the surface with a deceleration from 13,000 MPH to zero within the planned time frame of under ten minutes.
The ultimate objective of the mission is to determine whether or not Mars is or ever was suitable for hosting microbial life forms. The cells of prokaryotes and eukaryotes have two common characteristics. That is, both have a plasma membrane and cytoplasma.
Prokaryotes have a simpler construction while the eukaryotes contain a nucleus. Scientists would be looking initially for prokaryotes in the form of bacteria and cyanobacteria; such as, blue green algae. Next in the life chain are the eukaryotes consisting of protozoa, fungi, plants and lastly animals.
The Martian atmosphere is 95% carbon dioxide, nearly 3% oxygen 2% argon, with trace quantities of oxygen, carbon monoxide, water vapor and ozone. The density of Mars is about 25-30 % less than planet Earth. In addition, gravity is
slightly over 1/3 the size of Earth's. A smaller gravitational force could have
important implications for humans on Mars since there would be less stress on
internal organs in an atmosphere with a fraction of the gravitational pull as earth.
For Mars to sustain life-particularly human life, scientists would be required to construct a geodome concept with extensive tree planting to maintain a viable oxygen/CO 2 cycle together with existing water harnessed from the middle to high altitude regions on Mars or from brine. Sunlight would be problematic because the planet gets approximately half of the natural sunlight of earth.
Mars was once warm enough for liquid water to cover a portion of the planet. Ice formed at the poles as on Earth. If a large enough volume of water is determined to be present on Mars or its south polar cap, then the next step would be to harness the water for purposes of sustaining life in the not too distant future.