Life on Mars – Curiosity wants to know the odds

Science and Technology

Despite the slight possibility of incurring the wrath of a Roman War God, humans have been very, very curious about our neighbouring planet, Mars – starting with playing the scientific voyeur through the most basic of telescopes, to several botched attempts at space missions. Commonly referred to as the Red Planet, because of the copious amounts of iron oxide on its surface, Mars has been the subject of many a debate and musing regarding its environment and the biggest question of all time – whether there are any forms of extra-terrestrial life forms surviving on it.

Gale Crater, Mars: this is the landing site for the Mars Science Laboratory (MSL) mission rover, Curiosity. Gale Crater is 154km in diameter. The ellipse at top left is the predicted landing region, an area about 20km long and 7km wide./Science Photo Library

NASA is currently waiting on tenterhooks for their latest rover, Curiosity, to land on the “Red Planet”, which is scheduled to land at 6.31 (BST) this morning in the vast Gale Crater, where it will begin its mission by exploring an alluvial fan – which is a pattern of sediments thought to be created by flowing water. The rover is expected to explore Mars for one Martian year (687 Earth days) sampling rocks.

“We expect to land downslope of the alluvial fan, and since water flows downhill, we’re optimistic we’ll find evidence for an ancient watery environment there… if there was ground water, or a lake there, then it’s possible this was once a habitable environment,” said John Grotzinger, a geologist and project scientist working on the Mars Science Laboratory mission.

The Curiosity rover has four scientific goals:

  • Determining whether life ever arose on Mars

Before considering the possibility of life on Mars, scientists must first determine whether the environmental conditions present are capable of supporting life. Two previous rovers, Spirit and Opportunity, discovered promising evidence suggesting the presence of water, and now scientists are hoping to strike gold and find more things necessary for life to thrive – such as carbon, hydrogen, nitrogen, oxygen, phosphorous and sulphur. Thus, Curiosity will study carbon and water cycles on Mars to determine how levels of both have changed over time.

  • Characterising the climate

Mars’ current atmosphere is thin and cold, which does not bode well for any bodies of water that may have existed on the planet. However, a thicker and wetter atmosphere in the past may have provided a more optimal environment for microbial life. Curiosity will measure stable isotopes of elements of biological interest, such as carbon, and biosignatures, such as sudden changes in the abundance of particular isotopes, which may suggest the presence (past or present) of life.

  • Characterising the geology

As with Spirit and Opportunity, Curiosity will be searching for more evidence of rocks that were formed in the presence of water to further confirm that water was, at one point, present on Mars. It will also study its rocks and soil to further understand the geologic processes that have affected the Martian crust and surface.

  • Preparing for human exploration

Curiosity is a large rover, and if its landing is successful, it will help scientists to design and send the necessary equipment and infrastructure required for astronauts travelling to Mars. Curiosity will also analyse radiation levels and other hazards that astronauts may face in order to develop safety precautions.