Curiosity reaches Mars

Mars – what is there left to learn about the big Red Planet? It’s red, it’s cold and it’s dry – that much we know. But what other secrets does our nearest neighbour harbour?

Mars has been under scientific scrutiny for years, and while our knowledge of the Red Giant has increased vastly, we have only scratched the surface in terms of the secrets the planet has to offer.

Perhaps one of the biggest head-scratchers was whether there is liquid water on the planet – evidence suggests there once was because the landscape appears to have been sculpted by flowing water. Which links nicely with another mystery – since water is an essential part of the process – is there and has there ever been life on Mars?

NASA’s Curiosity Rover is due to land near Mars’ equator, in the Gale Crater on 6^th August, and will set about looking for clues as to whether there has ever been life on the planet. The fourth rock from the Sun is most promising to harbour life thanks to its similarity to Earth. It experiences seasons similar to those on Earth thanks to a 25% tilt in its axis, and its days are of similar length – 24 hours and 39 minutes. However, its temperature is a rather chilly -53°C and its atmosphere is 95% carbon dioxide – not ideal for complex organisms like us.

But that’s not what scientists working on the Mars Science Laboratory Mission hope to find. Their mission to Mars is looking for much simpler microorganisms.

The $2.5 billion rover is equipped with ten instruments ranging from an Alpha Particle X-ray Spectrometer to a Radiation Assessment Detector to various types of camera which will prod, poke and sample the rocks, soil and atmosphere of the Gale Crater to yield evidence of past or present habitable environments.

There are three important conditions for habitability – liquid water, other chemical ingredients utilised by life, like organic molecules, and a source of energy. Evidence suggests the Gale Crater is rich in clay and sulphate deposits and was once wet, as were other parts on the planet. Curiosity will study the strata of the crater to identify the environmental conditions when each layer was deposited.

It will also look for further evidence and inventory other ingredients, including nitrogen, phosphorus, sulphur and oxygen, searching for the chemical building blocks of life and identifying features that may record the actions of biologically relevant processes.

Curiosity will study the role of the water cycle on the planet, monitoring the release of water from sulphate salts – thought to retain trace amounts of liquid – in the warmer hours and reabsorption by salt deposits during the colder hours, a process which may be of relevance to past habitability. The rover will assess the long timescale atmospheric evolution and determine the present state, distribution and cycling of water and carbon dioxide.

So the rover will be looking for preserved signs of life, but is not actually designed to detect active processes. NASA scientists say Curiosity is not designed to answer whether life exists on Mars by itself, and depending on what it finds, further exploration of the planet in future missions will answer the eternal question.

Curiosity’s mission is expected to last one Martian year – approximately 98 weeks – with scientists relaying instructions for investigation to the rover on a daily basis. But if the rover is still in good working order NASA is open to extending the mission to look at higher levels of the crater, which could yield more results.

But what if Curiosity doesn’t confirm what we’re expecting? That could be $2.5 billion wasted – but NASA say that finding conditions that didn’t favour life will be as important as finding that life did exist on Mars. The findings could give important insight into the differences and similarities between early Earth and early Mars.

So whether life existed on Mars at one time will become clear in the coming years, but I for one will be awaiting the findings of Curiosity’s mission with bated breath. Who knows, it could even be another step towards a manned mission to Mars.

• Author Kerry Taylor Smith - Web Editor, Laboratory News