Aug 11. Nas has begun to publish the first colour photos sent back by Curiousity and the  Mars Reconnaissance Orbiter.

Here's a selection.

For more, see www.nasa.gov.

Gale Crater panorama. Click to zoom.

Blast marks left by Curiosity.

The mountainous rim of the crater in the distance.

Aug 7: Nasa's $3 billion Curiosity rover has touched down on Mars (see http://www.nasa.gov).

The rover, which landed shortly after 5.30pm NZ time yesterday, will search for traces of so-called extremophile lifeforms.

It immediately began to transmit images (right) albeit tiny 64x64 pixel black and white format.

Professor Craig Cary of Waikato University studies life in extreme environments like the Dry Valleys of Antarctica, widely considered to have the most Mars-like conditions of any place on Earth. He comments:

"The possibility of finding life is absolutely there. For life, you need water, and you need a source of energy. The problem on Mars is the availability of water.

"All life forms need water, but the question is: at what level? We know there are organisms that can live in ice, for example, because ice has a tendency to create little channels that remain liquid even though the rest of the ice is frozen.

"Antarctic researchers have found bacteria that are hundreds of thousands of years old, dormant but still alive, in these channels. So if there's permafrost or ice underground, it's a possibility.

"The problem with Mars is that it's a big planet. You can't pick a location that you can be absolutely certain is the right place to go looking – it's a gamble." 

Curiosity handed in the 3.8 billion-year-old Gale Crater near the planet's equator, an area rich in minerals that form in the presence of water.

From golf cart to Mini Cooper
The biggest technical differences between Curiosity and previous Nasa Mars rovers is its sheer size.

"Curiosity is huge in comparison. Spirit and Opportunity were maybe the size of a golf cart, Curiosity is the size of a Mini Cooper, weighs 900kg, is twice as long, five times as heavy and produces about three times as much power," says Dr Allan McInnes, Senior Lecturer, University of Canterbury School of Electrical and Computer Engineering.

Dr McInnes was a systems engineer working on the Mars rover programme from 2000-03 and worked on the Spirit and Opportunity rovers. 

"Curiosity is specifically designed to answer some of the questions that will help with future manned Mars missions," he says.

"One of the primary mission goals is to make an extensive study of surface radiation levels and really understand what's going on there. If you are going to put people on Mars, you want to make sure they will not be exposed to extreme radiation."

The six-wheel, nuclear-powered Curiosity is expected to operate for around two years, using lasers and drills. With its plutonium fuel source, the rover could potentially work for decades.