A rover and a helicopter are preparing to land on Mars, aiming to offer humans the opportunity to answer an enduring question: has life ever emerged on another planet?
Nasa’s ninth mission to descend on the cold, dry red planet will be steered by a $2.7bn (£2.1bn) car-sized rover – christened Perseverance by two teenagers in the US – after it touches down on Thursday following a seven-month interplanetary journey.
Previous Mars missions, including Curiosity and Opportunity, have shown that Mars was once a wet planet with an environment potentially supportive of life billions of years ago. Astrobiologists hope this latest mission can offer some evidence to prove whether or not that was the case.
Perseverance is carrying a clutch of instruments designed to analyse rocks for chemical hallmarks of life, or “biosignatures”, and will also store other samples from the planet’s surface. Future missions, fuelled by Europe and the US, will retrieve these samples and return them to Earth.
Apart from new instruments and an upgraded autopilot system, engineers have also given Perseverance the ability to deploy a diminutive helicopter. Called Ingenuity, the 1.8kg helicopter is the first flying machine ever sent to another planet, and could serve as a “pathfinder” to discover inaccessible areas or as a scout for future rovers.
Mission controllers are steering Perseverance towards the 28-mile-wide (45km-wide) Jezero crater, north of the planet’s equator. The site was chosen for its promise for preserving signs of life – it was once home to an ancient lake and river delta that may have collected and buried microbes and locked them within rocks.
But with its low gravity and rarefied atmosphere, Mars is hardly a hospitable destination – more than half of the Nasa spacecraft sent there have blown up or crashed, thanks to hardware and software problems. Nasa’s new generation of rovers, including Perseverance, rely on a rocket platform called a sky crane to lower it on to Mars’s surface.
After atmospheric friction slows down Perseverance – which weighs more than a tonne – a parachute will pop out and reduce the rover’s speed to a few hundred miles an hour.
Once the sky crane’s engines fire, the probe will slow down until it hovers about 20 metres above Mars’s surface. Cables deployed by the crane will carefully lower the rover and once it touches the surface, the cables will be cut and the sky crane will fly away to make its own uncontrolled landing at a safe distance.
“I am happily nervous, in anticipation of the words ‘we are safe on Mars’,” said the astrobiologist Susanne Schwenzer of the Open University.
“Having watched the Curiosity landing live, and knowing it can work, makes me optimistic, but of course, landing on another planet … is never easy, never routine.”