NASA rover finds 4B year old river delta on Mars
19 Mar 2026

NASA's Perseverance rover has discovered the remains of an ancient river delta buried deep beneath the surface of Mars.

The discovery, made using ground-penetrating radar, is one of the oldest pieces of evidence showing how water once flowed on the Red Planet.

The findings were based on data collected by the rover's RIMFAX instrument.

Dating back to 3.7-4.2 billion years ago
Exploration details

The six-wheeled rover traveled 6.12km inside Jezero Crater, an area in the Martian northern hemisphere that was once thought to be a water-rich environment with an ancient lake basin.

Perseverance uncovered geological features as deep as 115 feet (35m) underground during its journey.

The findings suggest that the now-buried delta dates back to some 3.7-4.2 billion years ago, making it one of the earliest indicators of water activity on Mars's surface.

RIMFAX instrument
Technological breakthrough

Perseverance's RIMFAX instrument sends radar pulses into the ground and records their reflections, creating a three-dimensional map of subsurface features.

The new findings were based on RIMFAX's deepest data collected to date, from September 2023 to February 2024 over a span of 250 Martian days.

This advanced technology has been instrumental in revealing the complex geological history of Mars and its potential for past life.

Evidence of wet past
Life potential

The discovery of the buried river delta adds to the growing evidence of Mars's wet past, a key factor in the possibility of past life on the planet.

"From the features mapped by RIMFAX, we believe that Jezero Crater hosted an ancient water-rich environment, capable of biosignature preservation that existed prior to the formation of Jezero's Western Delta," said UCLA planetary scientist Emily Cardarelli.

Liquid water on Mars?
Geological diversity

The discovery of the ancient river delta is just one of many pieces of evidence pointing to the presence of liquid water on Mars.

"Over time, we've seen more and more evidence for liquid water on the Martian surface at various rover landing sites," Cardarelli said.

"Mars is diverse, and each rover mission reveals another piece of its puzzling past and the early development of our rocky neighbor."