Mars 2020 mission: Nasa rover to use X-ray techniques to find signs of life

NASA's Mars 2020 rover mission, which aims to look for signs of past life on the Red Planet, will use smart X-ray techniques originally developed to find the oldest life on Earth, according to a mission scientist.

"Previous missions to Mars have used a relatively broad brush - analysing average chemistry over roughly the size of a postage stamp - to 'follow the water' and seek ancient habitable environments," said the mission's Deputy Project Scientist Ken Williford.

"Mars 2020 takes the next natural step in its direct search for evidence of ancient microbial life, focusing measurements to the microbial scale and producing high-resolution maps over similarly postage stamp-sized analytical areas," Williford said while speaking at the Goldschmidt geochemistry conference in Paris where he presented the methods to be adopted.

Rather than using "bulk" geochemistry techniques that measure the average composition of a rock, Mars 2020 is developing new capabilities including X-ray fluorescence and Raman spectroscopy to map the elemental, mineral, and organic composition of rocks at high spatial resolution, with analytical spot sizes about the width of a human hair.

Understanding the spatial distribution of chemical features preserved in ancient rocks is key to determining whether or not they were formed by life.

The instruments in development for Mars 2020 have roots in the search for the earliest signs of life on Earth, as well as life in extreme environments - deep underground, or in hydrothermal settings along ocean-floor ridges.

When these methods have been applied on Earth they have enabled scientists to lower limits of detection or to better understand formerly ambiguous observations.

In addition, the Mars 2020 mission will use the knowledge gained from its scientific exploration to select and collect key samples that could one day be examined in laboratories back on Earth.

About 30-40 rock and sediment core samples, each about 15 grams, will be hermetically sealed in titanium tubes and deposited in a safe location on the surface of Mars for possible retrieval by a future mission.

"Mars 2020 represents a crucial first step towards a possible Mars sample return. Our objective is to collect a diverse set of samples from our landing site with the best potential to preserve records of the evolution of Mars - including the presence of life if it was there," Williford said.

"We'll use our onboard instruments to provide the critical field context that future scientists would need to understand the measurements made back on Earth," Williford added.