The mission statement for Journey to Mars declares that Nasa expects to land an astronaut on the Red Planet by the mid-2030’s. But in order to achieve this goal, Nasa will need to develop a new planetary exploration vehicle.
Travelling to Mars is comparatively easy, as a question of time (approximately seven months) and resources. However, what happens when astronauts arrive there presents a new challenge. Mars is vastly different to the moon, the only other astral body we have set foot on. As such, the Lunar Roving Vehicle, which accompanied the Apollo astronauts on their Moon missions, is unsuitable for the Mars missions.
Both the Moon and Mars are quite dusty environments; however the pressures, temperatures and radiation levels are all quite different. For future missions to Mars, Nasa engineers need to develop innovative technology that can operate in this new environment.
The Space Exploration Vehicle will follow in the footsteps of the Curiosity rover (Credit: Nasa/JPL)
Up until now, Mars Rovers, such as Spirit and Curiosity, have allowed Earth-based scientists to safely explore the Red Planet using remote controlled drones. However, this is not a time-efficient method. “That's why it’s so important to send humans to Mars,” says Dr Maggie Lieu, a research fellow at the European Space Agency. “They would be able to do the same work over the lifetime of a rover within a few hours.”
There is also the time-delay factor to consider. The distance between Earth and Mars varies between 34 million miles and 250 million miles, depending on the relative positions of the planets in their orbits around the Sun. This means that communications between a Mars rover and the control room on Earth suffer from a significant time delay. “It takes anywhere between eight to 20 minutes one way to communicate,” says Dr Lieu. “So, it’s really difficult for rovers to react to, say, if they were driving off a cliff!”
Although no one has ever been to Mars and no surface samples have ever been returned, the red planet has been mapped by orbiting satellites, like the Maven, as well as the Mars rovers. Through these observations, scientists have determined that the reddish colour of Mars comes from the high iron oxide (rust) content at the planet’s surface.
The greatest challenge for life on Mars is the wind, which together with the dust creates massive dust storms
Surface temperature measurements taken by the Mars rovers have been recorded between a chilly -150°C (-238F ) (the Antarctic is usually “only” approximately -40°C (-40F) and a British spring time 20°C (68F). The surface pressure of Mars is 600Pa (compared to Earth’s 100,000Pa) and it has an atmosphere comprising mostly of carbon dioxide, with traces of nitrogen, oxygen, argon and other gases.
However, the greatest challenge for life on Mars is the wind, which whips up the loose detritus of the Martian landscape to create massive dust storms. Localised storms can last less than a day, but global dust storms may cover the entire planet for as long as a month. As well as hampering visibility, these dust storms can interrupt communication and solar power generation. The abrasive action and acidic content of the dust (from highly corrosive perchlorates, a salt produced from perchloric acid) can damage unprotected vehicles.
Less powerful winds known as ‘dust-devils’, however, were found to clean the solar panels on the Rovers and Landers, increasing their solar power-generating efficiency.
The lunar rovers were only allowed to travel up to six miles from the module, in case they broke down (Credit: Science Photo Library)
For the forthcoming Mars colonisation video game Pioneer: Mars, JCB designed a series of Martian exploration vehicles for various roles. These vehicles varied from an all-terrain exploration vehicle to a heavy-duty tracked excavator.
JCB approached these concept designs as a thought exercise for visualising what a machine for work on Mars might look like. “The aim was to create a range of versatile machines that could withstand the challenges and undulations of the Red Planet,” explains Ben Watson, the head of industrial design for JCB. “The excavator, for example, had quad-tracks to cope with those extreme undulations and contours they might experience.
“It's a heavy excavator with a large bucket. With the low pressure and low gravity on Mars, I assume you can load a lot more with the same power ratio as we have on Earth," says Watson. "But obviously, getting all that stuff up there would be an issue, with weight being a premium.”
As well as being pressurised, the cabin segment of the Space Exploration Vehicle is heavily shielded and can also be used as a storm shelter
While JCB’s various vehicles were designed to be function-specific, for a Mars mission the reality is far different.
The Space Exploration Vehicle that Nasa is developing for their Mars missions will have a modular design, enabling it to fulfil several tasks.
Unlike the smaller Lunar Roving Vehicle, Nasa’s Space Exploration Vehicle prototype is mounted on six wheels, each measuring over three feet in diameter and a foot wide. It comes with its own pressurised cabin, which will allow astronauts to travel further without the having to rely on space suits.
The vehicle will have to withstand the severe dust storms that rage across Mars (Credit: Science Photo Library)
A modular design allows the pressurised cabin to be detached from the chassis part – called “Chariot” – of the Space Exploration Vehicle. This allows Chariot to be used for carrying cargo or to be fitted with winches, cranes, bulldozer blades or cable reels for a variety of missions, such as repositioning solar-powered recharging stations.
The pressurised cabin segment of the Space Exploration Vehicle also allows two astronauts to comfortably live inside the cabin for up 14 days, and – in an emergency – accommodates up to four people. Rather than the standard airlock, astronauts enter via a “suitport”, which allows astronauts easy access to performing space walks as and when required.
As well as being pressurised, the cabin segment of the Space Exploration Vehicle is heavily shielded and can also be used as a storm shelter, providing astronauts with over three days’ protection against solar particle events, such as those caused by solar flares.
Vehicles like Nasa’s Space Exploration Vehicles will allow astronauts to travel further and be able to perform tasks without exposing the astronauts to undue risk
One of the key concerns for any Mars vehicle will be its reliability. Requesting roadside assistance in the event of breakdown is impractical for the Space Exploration Vehicle, when the nearest vehicle recovery provider is over 35 million miles away. As such, any planetary vehicles will need to be both highly reliable and, if the worst should happen, easily repairable.
Manned planetary exploration is limited by how quickly the astronauts are able to return to a safe, pressurised environment in the event of an emergency. In the case of the Apollo missions, this was limited to how far the astronauts could walk back to the lander module, in the event that the lunar rover broke down. This limited the astronauts to travelling no further than six miles from the Lander. The pressurised cabin of the Space Exploration Vehicle, now allows a potential exploratory range of up to 125 miles.
The vehicle can act as an emergency shelter for up to 14 days (Credit: Nasa)
Much like the electric cars currently being deployed here on Earth, the Space Exploration Vehicle will rely on batteries for power. However, batteries used on the Space Exploration Vehicle will provide far greater power-density (the power-to-size ratio) than conventional batteries on Earth. These batteries will be recharged through solar power panels. Alternatively, replaceable lithium-ion batteries could also be used.
With manned missions to Mars moving ever closer to reality, astronauts will need new and reliable vehicle technology for safely exploring the Martian surface. Vehicles like Nasa’s Space Exploration Vehicles will allow astronauts to travel further and be able to perform tasks without exposing the astronauts to undue risk. “You are not going to be able to take a whole army of specific machines,” concludes Watson from JCB. “Having a range of versatile machines who can do lots of tasks feels like a really strong direction.”
If you liked this story, sign up for the weekly bbc.com features newsletter, called “If You Only Read 6 Things This Week”. A handpicked selection of stories from BBC Future, Earth, Culture, Capital, Travel and Autos, delivered to your inbox every Friday.