Was there ever life on Mars? Now that Perseverance has landed, Imperial scientists working with NASA’s Mars 2020 mission might soon find out.

After a seven-month journey, NASA's Perseverance rover, a scientific laboratory the size of a car, made its final descent to the Red Planet on 18 February 2021 to begin a search for traces of life.

Lakes are fantastic at fostering and preserving life, so if there is any to be found then it could well be in the Jezero crater. Professor Sanjeev Gupta Department of Earth Science and Engineering

Perseverance landed in Mars's 28-mile wide Jezero crater, which contains sediments of an ancient river delta and where evidence of past life could be preserved if it ever existed on Mars. The rover will use its drill to collect samples from Martian rocks before storing the sample cores in tubes on the Martian surface ready to return them to Earth in 2030. 

The rover descended at nearly 1,000 miles per hour through the Martian atmosphere before retro rockets kicked in to reduce its speed. At around 20 metres from the surface the rover itself will be lowered by a sky crane to its target destination.

Supported by funds from the UK Space Agency, researchers at Imperial and its neighbour, the Natural History Museum, will help decide which samples are sent to Earth in a search for evidence of ancient microbial life. 

This could be the mission that answers the question of whether life ever existed on Mars...the molecular fingerprints of Martian life need not only to have been generated, but also preserved over billions of years. Professor Mark Sephton Head, Department of Earth Science and Engineering

Imperial researchers are playing a major role in the mission. Back on Earth, Imperial’s Professor Sanjeev Gupta, a geologist, is helping NASA oversee mission operations from a science and engineering point of view, helping decide where the rover will go and what it will sample. Imperial’s Professor Mark Sephton, an astrobiologist, is helping to identify samples of Mars that could contain evidence of past life.

Meanwhile, researchers from the Natural History Museum will be studying the mineralogy, chemistry, and environments recorded in sedimentary rocks exposed in the Jezero crater and looking the potential for signatures of ancient microbial life preserved within. 

Professor Gupta, of Imperial’s Department of Earth Science and Engineering, is working closely with the science team to develop the mission's strategic science vision, making sure that it fulfils its science objectives. Day-to-day he will work with the engineers in rover operations to search for samples of rocks for a future return to Earth.  

He said: “It is crucial to understand what the Martian climate was like early in Mars' history and whether it was habitable for life. Analysis of data from instruments onboard Perseverance will help us define the best spots to collect rock samples for future return to Earth. Lakes are fantastic at fostering and preserving life, so if there is any to be found then it could well be in the Jezero crater.

“Laboratory analyses of such samples on Earth will enable us search for morphological and chemical signatures of ancient life on Mars and also answer key questions about Mars' geological evolution.” 

Professor Sephton, Head of the Department of Earth Science and Engineering, is an astrobiologist who specialises in recognising the organic records of past life in rocks and will help the team select samples for eventual return to Earth.

He said: "This could be the mission that answers the question of whether life ever existed on Mars. Evidence of biology on another planet would mean that life on Earth was not alone. However, the molecular fingerprints of Martian life need not only to have been generated, but also preserved over billions of years.

“We need to choose the best samples from a planet's worth of opportunities and return around half a kilogram of material from Mars. Once safely back on Earth the samples of Mars will reveal their secrets when examined by the most powerful instruments available.”

Scientific goals

Perseverance will focus on finding the signs of life and reconstructing the geological history of Mars. Its onboard carbon-searching instruments will seek out the building blocks of life by analysing samples of rock from the surface. It will select samples before collecting them using the drill and then sealing them in sample tubes. 

When the rover reaches a suitable location, the rover will drop the tubes on the surface of Mars to be collected by a future retrieval mission, the Sample Fetch rover. Back on Earth, a team will curate and study the rocks for evidence of microbial life. 

The rover also carries the Ingenuity Mars Helicopter, which will make the first attempt at powered, controlled flight on another planet by flying short distances from the rover. A successful test of the helicopter could lead to more flying probes to survey the landscape of other planets.

Perseverance will also trial new technologies to help astronauts make future expeditions to Mars. These include testing a method for producing oxygen from the Martian atmosphere, known as MOXIE, on which Imperial's Professor Tom Pike is co-investigator.

We need to understand the scale up that would be needed for future human exploration. Professor Tom Pike Department of Electrical and Electronic Engineering

Professor Pike is looking at the problems that might be caused by dust clogging the filters of its electrolytic converter. He said: “We did experiments in Mars simulators on Earth to try to see how quickly the filters might build up enough dust to reduce MOXIE’s oxygen production. You need to have a massive throughput of Mars's atmosphere to make a significant amount of oxygen, so even if there is no problem with our experiment on Mars, we need to understand the scale up that would be needed for future human exploration.” 

The rover will also look at identifying other resources like subsurface water, improving landing techniques, and characterising weather and other potential environmental conditions that could affect future astronauts living and working on Mars. 

On 18 February, Imperial scientists Drs Steve Banham, Rob Barnes and Sam Royle from the Department of Earth Science and Engineering answered questions from the public in a Reddit ‘Ask Me Anything’ event on the forum r/Space live.

Professors Gupta and Sephton also gave a lecture on the mission for Imperial’s Science Breaks programme and answered questions from interested audience members.

This news story was adapted from a press release by the UK Space Agency.

Video: UK Space Agency with additional footage from NASA