In 2003, scientists found Chile's Atacama desert so dry it had no detectable DNA. Now it's helping prepare for Mars missions

Mars has long captivated scientists and space agencies. From NASA and ISRO to SpaceX founder Elon Musk, efforts to explore the Red Planet have intensified over the past few decades. While robotic missions continue to uncover Mars' secrets, researchers also need Earth-based locations that closely resemble Martian conditions to test equipment and study how life might survive in extreme environments.

Fortunately, scientists have found a way to mimic the Red Planet's atmosphere without leaving earth, in Chile's Atacama Desert.

Why the Atacama Desert resembles Mars

Stretching across northern Chile, the Atacama Desert is the driest non-polar desert on Earth. Its combination of extreme dryness, unusual soil chemistry and minimal biological activity makes it one of the best natural laboratories for studying Mars.


Rainfall is so rare that many parts of the desert go years without measurable precipitation. Near Yungay, about 80 kilometres from Antofagasta, researchers recorded just one rainfall event of 2.3 millimetres over four years. During that period, liquid water was present in the soil for only 65 to 85 hours, according to research published in Astrobiology. Although dew formed regularly, it contributed very little moisture.

Even the powerful 1997-98 El Niño weather event, which affected deserts farther north, failed to bring rain to the central Atacama.

NASA field observations also indicate that some locations receive only around one centimetre of rainfall every ten years, making average annual rainfall almost meaningless because many years record no rain at all.

The world's longest recorded dry spell

The Atacama is home to one of the most extraordinary rainfall records on Earth.

In Arica, a coastal city on the desert's northern edge, the World Meteorological Organization recognizes a 172-month dry spell—from October 1903 to January 1918—during which no measurable rainfall was recorded. Because Arica has maintained continuous rain-gauge observations for more than a century, scientists consider this one of the world's most reliable long-term drought records.

The 2003 discovery that surprised scientists

In November 2003, a research team led by Rafael Navarro-González and Chris McKay analysed soil collected from the Atacama Desert.

The results were remarkable.

Scientists found extremely little biological activity. Only trace amounts of organic material were detected, and very few bacteria could be grown in laboratory conditions. Most strikingly, two soil samples contained no detectable DNA.

The team also performed experiments similar to those carried out by NASA's Viking landers on Mars in 1976. The Atacama soil broke down organic material without the help of living organisms—a chemical behaviour that closely resembles what scientists expect could happen on Mars.

The findings suggested that even if organic molecules exist on Mars, they could be destroyed by chemical reactions before instruments detect them. This has important implications for future life-detection missions.

An even drier place than Yungay

For years, researchers used Yungay as the primary Mars analogue because it was easy to access.

However, in 2015, Armando Azua-Bustos and his colleagues identified an even more extreme site called María Elena South.

The researchers measured an average humidity of 17.3% at María Elena South compared with 28.8% at Yungay. These humidity levels closely match those recorded by NASA's Curiosity rover inside Gale Crater on Mars, making María Elena South one of the closest terrestrial environments to the Martian surface.

Why the Atacama is so dry

The Atacama's extraordinary aridity results from several natural factors working together.

The Andes Mountains block moisture-laden air arriving from the Amazon Basin. Along Chile's coast, the cold Humboldt Current cools the lower atmosphere, creating a temperature inversion that suppresses cloud formation. A persistent subtropical high-pressure system further pushes air downward, preventing rainfall.

These combined geographical and atmospheric conditions have produced soil chemistry that closely resembles that of Mars.

Helping scientists prepare for Mars

The Atacama Desert has become a critical testing ground for planetary science.

Researchers use it to evaluate scientific instruments, study how organic molecules survive under extreme conditions and understand how future Mars missions should search for evidence of life.

The discovery that Atacama soil can chemically destroy organic material without biological activity has been particularly influential. It demonstrated that instruments designed to detect life can produce misleading results under Martian-like conditions, prompting scientists to refine future mission strategies.

Every new observation—from rare rainfall events and record-breaking droughts to the discovery of soils with almost no detectable DNA—helps researchers better understand the Red Planet without ever leaving Earth.

As space agencies prepare for increasingly ambitious Mars missions, Chile's Atacama Desert continues to serve as one of Earth's most valuable natural laboratories for exploring the possibility of life beyond our planet.