NASA scientists have been left ‘baffled’ after a new first of its kind experiment on Mars found that oxygen levels fluctuate in a way that can’t be explained.
A portable chemistry lab on the Curiosity Rover has been sampling the air above the Gale Crater on the Red Planet for three Martian years (or about six Earth years).
Scientists have used this data to measure the way the gases that fill the air above the surface of the crater change with the seasons.
They discovered that the amount of oxygen in the atmosphere goes up by 30 per cent in the spring then drops back to normal by the autumn in a way that cannot be explained by any known chemical process.
The Curiosity Rover, which is now the only operating craft on Mars has a chemistry label that has been sampling the air around the Gale crater to find out what the surface level atmosphere on the Red Planet contains
‘We’re struggling to explain this,’ said Melissa Trainer, a planetary scientist at NASA’s Goddard Space Flight Center who led the research.
‘The fact that the oxygen behaviour isn’t perfectly repeatable every season makes us think that it’s not an issue that has to do with atmospheric dynamics. It has to be some chemical source and sink that we can’t yet account for.’
The Sample Analysis at Mars (SAM) portable chemistry lab on the Curiosity Rover confirmed the Martian atmosphere at the surface is made up of carbon dioxide, nitrogen, argon, oxygen and carbon monoxide.
About 95 per cent of the surface atmosphere is carbon dioxide, followed by 2.6 per cent molecular nitrogen, 1.9 per cent argon, 0.16 per cent oxygen and 0.06 per cent carbon monoxide.
They found that nitrogen and argon follow a predictable seasonal patter. It waxes and wanes in contraction in the crater throughout the year and is relative to how much CO2 is in the air.
WHAT IS IN THE MARTIAN ATMOSPHERE?
The Martian atmosphere is made up of a number of chemicals.
These include oxygen, carbon dioxide, carbon monoxide, water vapour, nitrogen and argon.
Carbon dioxide: 94.9%
Carbon monoxide: 0.0747%
Water vapour: 0.03% (variable)
The surface temperature on the planet ranges from 68F at noon at the equator to below -243F at the poles.
They expected oxygen to do the same but were shocked to find it didn’t.
Researchers found the amount of oxygen in the air rose throughout spring and summer by as much as 30% then dropped back to levels predicted yb known chemistry in the autumn.
This pattern repeated every spring but the amount of oxygen added to the atmosphere varied each year. NASA says this could suggest something is producing it then taking it away.
‘The first time we saw that, it was just mind-boggling,’ said Sushil Atreya, professor of climate and space sciences at the University of Michigan.
The team checked the equipment to see if it was faulty and causing false readings, but everything was working properly.
They then speculated on whether the unexpected short term rise and fall in oxygen levels could be due to water molecules releasing oxygen that then breaks apart in the atmosphere.
This was dismissed as it would take five times more water above Mars than is available to produce the extra oxygen being detected.
The NASA Viking landers, one of which is seen here at a Martian sunset in 1978, arrived on the Red Planet in the 1970s. They were able to study the atmosphere but only did so for a few days
The only other spacecraft that had instruments able to measure the Martian air near the ground were the NASA Viking landers which arrived on the planet in 1976.
The Viking lander survey of the atmosphere only covered a few Martian days so couldn’t reveal any seasonal patterns.
These new measurements by Curiosity have produced the first multi-seasonal picture of the air at the surface of Mars.
The study of the atmosphere was conducted above the gale crater, thought to be a dry lake about 3.5billion years old.
The crater is 96 miles in diameter and holds a mountain called Aeolis Mons that rises 18,000ft from its surface.
In the first experiment of its kind, scientists have used this data to measure the seasonal changes in the gases that fill the air above the surface of the Gale crater on Mars
This isn’t the first chemical mystery to be revealed by Curiosity. There is a similar surprising fluctuation in the level of methane found in the air above the crater, NASA confirmed.
Scientists think the two could be linked as there are ‘unpredictable but periodic’ crossovers when the two unusual effects happen at the same time.
‘We’re beginning to see this tantalising correlation between methane and oxygen for a good part of the Mars year,’ Dr Atreya said. ‘I think there’s something to it. I just don’t have the answers yet. Nobody does.’
The intrepid Curiosity rover, pictured here on November 3, 2019 — which has been exploring Mars’ Gale impact crater since August 2012 — is studying Mars’ surface rocks and looking for signs of life
Oxygen and methane can be produced biologically from things like microbes and abiotically from chemistry linked to water and rocks.
While researchers are examining all possibilities for the strange rise and fall in oxygen levels, they don’t think it is linked to anything biological.
They believe the Martian soil – which is rich in oxygen in the form of compounds such as hydrogen peroxide and percolates – could be one cause of the rise and fall but there isn’t enough evidence to confirm this.
‘We have not been able to come up with one process yet that produces the amount of oxygen we need, but we think it has to be something in the surface soil that changes seasonally’, said Timothy McConnochie from the research team.
‘There aren’t enough available oxygen atoms in the atmosphere to create the behaviour we see’.
NASA has put a call out to experts around the world to try and help them find a solution to the problem.
‘This is the first time where we’re seeing this interesting behaviour over multiple years. We don’t totally understand it,’ Dr Trainer said.
‘For me, this is an open call to all the smart people out there who are interested in this: See what you can come up with.’
The findings have been published in the Journal of Geophysical Research.
WHAT IS THE MARS CURIOSITY ROVER AND WHAT HAS IT ACHIEVED SO FAR?
The Mars Curiosity rover was initially launched from Cape Canaveral, an American Air Force station in Florida on November 26, 2011.
After embarking on a 350 million mile (560 million km) journey, the £1.8 billion ($2.5 billion) research vehicle touched down only 1.5 miles (2.4 km) away from the earmarked landing spot.
The Mars curiosity rover was initially intended to be a two-year mission to gather information to help answer if the planet could support life, has liquid water, study the climate and the geology of Mars an has since been active for more than 2,000 days
After a successful landing on August 6th, 2012, the rover has travelled about 11 miles (18 km).
It was launched on the Mars Science Laboratory (MSL) spacecraft and the rover constituted 23 per cent of the mass of the total mission.
With 80 kg (180 lb) of scientific instruments on board, the rover weighs a total of 899 kg (1,982 lb) and is powered by a plutonium fuel source.
The rover is 2.9 metres (9.5 ft) long by 2.7 metres (8.9 ft) wide by 2.2 metres (7.2 ft) in height.
Due to its success, the mission has been extended indefinitely and has now been active for over 2,000 days.
The rover has several scientific instruments on board, including the mastcam which consists of two cameras and can take high-resolution images and videos in real colour.
So far on the journey of the car-sized robot it has encountered an ancient streambed where liquid water used to flow, not long after it also discovered that billions of years ago, a nearby area known as Yellowknife Bay was part of a lake that could have supported microbial life.