NASA's Curiosity Mars rover has found evidence of key ingredients for life on Earth in Martian rock samples.

Mars' Curiosity Rover drilled samples from Gale crater, the site of an ancient lake. Scientists measured the total amount of organic carbon in Martian rocks using these samples for the first time, according to NASA

All known forms of life require organic carbon, which is carbon bound to a hydrogen atom. It is also possible for organic carbon to come from non-living sources, such as meteorites and volcanic eruptions.

In previous studies, organic carbon was detected in smaller amounts in Martian rock samples. The new measurements provide insight into the amount of carbon in organic compounds as a whole.

'Total organic carbon is one of several measurements that tell us how much material is available for prebiotic chemistry,' Jennifer Stern, lead author of the study and a space scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said.

'The amount of organic carbon we found is comparable to or even greater than what has been detected in rocks from very low-life places on Earth, such as parts of the Atacama Desert in South America, as well as in Mars meteorites.'

The Red Planet today is not a suitable environment for life, but evidence suggests that billions of years ago it was similar to Earth, with a thicker atmosphere and liquid water - essential components for life.

Curiosity has been exploring Gale Crater since 2012, where the 3.5-billion-year-old Yellowknife Bay formation contains the Martian samples. Before settling at the bottom of the lake, scientists believe that the sediment was formed by the physical and chemical weathering of volcanic rocks.

The rover used its Sample Analysis at Mars (SAM) instrument to analyze the fragments, which convert organic carbon into carbon dioxide using oxygen and high heat.

Scientists can determine the source of carbon by calculating how much carbon dioxide was produced and calculating the precise isotope ratio from that, according to the statement. Chemical elements have different isotopes according to how many neutrons they have in their cores.

'Isotopic composition can only provide information about the proportion of organic carbon and mineral carbon in this case,' Stern said.

'Biological origins are not entirely ruled out, but isotope analysis cannot really be used to support them, since the range overlaps with igneous (volcanic) carbon and meteoritic organic matter, which are the most likely sources of this organic carbon.'

Researchers also found chemical energy sources, oxygen, nitrogen, sulfur, and low acidity in Gale crater, in addition to organic carbon. 'If life had ever existed at this location, it would have provided a habitable environment,' Stern said.