Europe's first Mars rover: from Stevenage to outer space
PUBLISHED: 10:44 10 August 2018
The launch of Europe’s first rover to Mars is two years and counting. The engineers at the Stevenage site building it are putting it through its final paces so it can search for life
Mars has played on the imagination for centuries. From the Romans’ god of war to the invading B-movie Martians of the 1950s, the Red Planet has exerted a powerful fascination.
Now Hertfordshire is to play a key role in exploring the planet and the countdown has begun. Europe’s first Mars rover, which is being built in Stevenage, is scheduled to take off from Russia in two years’ time and land on Mars in 2021. It aims to answer one of the major scientific questions of our time – has life existed or still exists on Mars?
A prototype of the ExoMars rover has begun a demanding test campaign to ensure it can survive the rigours of launch and landing, as well as operations under the environmental conditions of Mars.
ExoMars is a joint endeavour between the European Space Agency and Russia’s Roscosmos, and the rover, being built at Airbus Defence and Space, will be the first of its kind to drill up to two metres below the surface and determine if evidence of life lies buried.
Abbie Hutty, senior spacecraft structures engineer, explains: ‘Our mission has a primary objective of finding life on Mars. We know enough about the surface to know it’s too hostile for life to survive there because of all the radiation that’s constantly bombarding it. We need to look below the surface. If there is any life still on Mars, that’s where we think it would still survive, or if we are looking at past life we might be able to find remnants of that life at that depth.’
The six-wheeled solar powered vehicle will use panoramic and close-up cameras and will drill for rock samples at various depths.
Its structure, as well as its electrical and thermal components, and the interfaces with its scientific instruments, have to be tested to check they can survive the journey through space and operations at its destination. A structural and thermal model of the rover was therefore recently transferred from Gunnels Wood Road to the Airbus site in Toulouse, France, where it is being shaken on a vibration table to ensure it can survive the intense juddering at rocket launch.
The model will also be subjected to the shocks associated with entering another planet’s atmosphere at high speed, and as parachutes open, and finally the touchdown on Mars’ surface.
There will be two months of tests under Mars atmospheric conditions, to ensure it can withstand the huge daily temperature shifts, as well as storms and radiation.
‘Some of the biggest challenges on Mars relate to the temperature,’ Abbie explains. ‘It’s really very cold. At night it can get down to -130°C. Everything in terms of the materials is very brittle at those low temperatures, so any impacts are much more damaging than they would be at warmer temperatures.
‘On Mars, it can shift 100°C from day to night. That means all the different materials are contracting and expanding due to those temperature changes, but at different rates, and that means they are trying to tear themselves apart from the other structural components.’
She adds that sand getting into mechanisms is a real issue, as well as dust storms. ‘Not only can you not see where you are going, but it will be blocking the light to our solar panels and getting into places we don’t want it.
‘The surface of Mars is also heavily irradiated, so we have to think about the damaging effect on software systems on board.’
The tests in France will be conducted in a chamber to simulate the low atmospheric pressure of Mars and its carbon dioxide-rich atmosphere.
A closed compartment inside the rover, where Martian soil samples will be analysed, will be thermally controlled to maintain temperatures between 20°C and -40°C.
A ‘Mars yard’, designed to mimic the surface and terrain of Mars, was established at Airbus in Stevenage in 2014 to put rover models through their paces.
‘We use it to develop the locomotion systems and navigation systems on the rover,’ Abbie explains. ‘How it drives and also how it looks ahead of itself and decides where it needs to go.
‘We’ve got sand here that’s been specially dried in a kiln so it doesn’t stick together. The surface of Mars is very dry and powdery.’
The rover will have an unmatched capability to autonomously navigate up to 70 metres a day with no outside guidance from ground control.
Abbie says, ‘It can take 24 minutes for a signal to get from the Earth to Mars. With autonomous navigation, the rover can look at what’s ahead of it and pick its own safe path through and navigate to its final destination.’
The launch to Mars is due in summer 2020 and the rover is scheduled to land there in January 2021. The completed rover will be shipped from Stevenage next summer for testing and further work before it is integrated into the rocket and descent module in Russia that will deliver it to the alien planet.
More than 40 missions have been dispatched to Mars since the early 1960s, but the first fully successful touchdowns had to wait until the arrival of the US Viking 1 in July, 1976, followed by Viking 2 in September the same year. Since then, there have been five more successful landings on the Red Planet – all by US spacecraft – as well as a number of failed attempts.
As part of the ExoMars project, the Trace Gas Orbiter was launched into space in 2016 and is now orbiting Mars looking for atmospheric gases that may be linked to active geological or biological processes. It will play a key role – relaying the rover’s data back to Earth, a capability already demonstrated with communication relays to NASA’s rovers currently on Mars.
The ExoMars Schiaparelli module – which was designed to demonstrate entry, descent and landing technologies on Mars – separated from the Trace Gas Orbiter in October 2016 as planned, but crash-landed on the Red Planet due to conflicting information in the onboard computer causing the descent sequence to end prematurely.
The current test campaign for the rover is expected to last until the beginning of this month, when the rover model will then move to Lavochkin in Moscow. Here it will be sealed inside a replica descent module and again subjected to vibration, shock and thermal tests.
Pietro Baglioni, the European Space Agency’s ExoMars rover team leader, says, ‘This campaign kicks off a series of tests that will verify the mechanical and thermal design of the ExoMars rover – essential preparation that brings us a step closer to roving on the Red Planet.’
Another test model will soon start an eight month-long campaign focusing on the rover’s movements and navigation over a variety of different ground types, ranging from fine-grained soil to larger boulders.
ExoMars marks a new era for European space exploration – advancing from remote observation to the surface of Mars. Hertfordshire is at the forefront of that, and its robot could make one of the biggest discoveries in human history.