The Oxford University professor digging for life on Mars from 140 million miles away in Oxford

The distance between Professor Scott McLennan’s desk at Oxford University and Mars is about 140 million miles, but it doesn’t stop him using his computer to direct Nasa’s latest spacecraft on the Red Planet’s surface.

He is a member of a team that controls the car-sized vehicle, named Curiosity, as they try to discover if Mars once had the right conditions to support life. 

Each member has a different area of expertise, such as geology or atmospheric science, or responsibility for the rover’s cameras and instruments.

Man on mission: Professor Scott McLeannan can control the Mars-roving Curiosity from the comfort of his study 

Prof McLennan says: ‘Every day Curiosity sends information back to Earth. That determines what we do and where we go next. To make anything happen, we have to give it meticulously planned instructions.’

Curiosity has sent home thousands of images of unprecedented clarity of the surface of Mars to help provide information to create a detailed picture of the planet’s past, when it was much warmer and had rushing rivers and deep lakes.

Thanks to experts such as Prof McLennan, Curiosity has collected and analysed rock samples in its on-board lab, suggesting that there may have been life on Mars three billion years ago.

So far, the evidence is inconclusive. But, says Prof McLennan, with Nasa’s next Mars mission due to launch in July, this may change. 

Curiosity, which is 10ft tall and 9ft wide, was launched in November 2011, reaching Mars nine months later. Its descent was carefully slowed by retro-rockets and a supersonic parachute. 

Landing at the bottom of the 100-mile-wide Gale Crater, it was designed to work for a minimum of a Martian year – about 687 days – but is still functioning.

It has a 7ft robotic arm, weighs about a ton and its power supply comes from a slug of plutonium.

Prof McLennan, 67, says Gale Crater is now arid but there is ‘evidence this was once a huge freshwater lake, which may have been hundreds of feet deep. Rivers tumbled down the crater walls and formed deltas when they reached the lake’s edge.’

Although midday temperatures there now sometimes rise only just above freezing, at night they plunge to minus 70C. 

But three billion years ago, ‘the climate may have been a bit like an English winter,’ says Prof McLennan.

So far, Curiosity has travelled 13 miles across the surface of the planet and climbed more than 1,400ft up the side of a mountain. 

Most impressively, last week it navigated a 30-degree gully between crags to reach the top of the escarpment. 

With its flat top above a line of vertical cliffs, to the untrained eye it looks like a Peak District moorland edge.

Curiosity’s next task, which it may accomplish this week, is to drill down and take a sample of powder from a rock slab.

Miles apart: The Curiosity may be 140 million miles apart and the professor's computer is able to direct its movements

Miles apart: The Curiosity may be 140 million miles apart and the professor’s computer is able to direct its movements

This will be dropped through a port into the rover, where tools will analyse the rock by heating it to more than 1,000C. It was these techniques that led to the discovery of organic carbon compounds that could be evidence of primitive life.

However, Mars scientists often repeat a comment by the late astronomer Carl Sagan that ‘extraordinary claims require extraordinary evidence’ – which is why no one is shouting that they have proof of life just yet.

Nevertheless, Prof McLennan says the next mission, Mars 2020, has been tailored by the attempt to find it. 

The new rover, Perseverance, is planned to land next year in a crater called Jezero.

He hopes that after two further missions, samples will be sent back to Earth and provide scientists with something that has so far been unattainable – examples of Martian sedimentary rock to analyse here, where tools such as electron microscopes might reveal fossils of single-celled organisms.

Whatever the outcome, Prof McLennan is sure it will be worth the wait: ‘All of us involved consider it an absolute privilege. Some days you get lost in the detail.

‘And then you step back and you simply marvel that you’re seeing something amazing that’s never been seen before.

‘If that doesn’t move you, nothing in science ever will.’