Cheyava Falls

**Cheyava Falls** is a rock found on Mars in 2024 by NASA's _Perseverance_ rover while it was looking around the Jezero crater. This rock, named after a Grand Canyon waterfall, has had attention due to its possibility of being evidence of ancient life on Mars. The rover's tools found organic compounds within the rock, which are needed for all known life. According to NASA, Cheyava Falls "possesses qualities that fit the definition of a possible indicator of ancient life".

## Discovery

This unusual rock, named Cheyava Falls, was found in 2024 by NASA's _Perseverance_ rover in Jezero crater. Cheyava Falls is has large white calcium sulfate veins and bands of reddish material, pointing to hematite, a mineral that gives Mars its rusty color. The veins are "filled with millimeter-size crystals of olivine". The rock has millimeter-sized off-white spots surrounded by black material, looking like "leopard spots". These spots contain iron and phosphate, elements often associated with microbial life. According to a seven-step scale called Confidence of Life Detection (CoLD) used by NASA astrobiologists, the rock is on Step One, showing a "possible signal" of life.

The "arrowhead-shaped rock" was found at the northern edge of Neretva Vallis area, on 18 July 2024, and is . On 21 July 2024, _Perseverance_ took a part of the rock that became its 22nd core sample that can be sent back to Earth by a future project. The rover took a "selfie" with the rock on 23 July 2025.

The sample from Cheyava Falls is called the **"Sapphire Canyon"**, while the formation where Cheyava Falls were found is called the "Bright Angel", a set of rocky outcrops on the northern and southern edges of Neretva Vallis, an ancient river valley  wide that was made by water rushing into Jezero crater.

The rock was studied by tools: the Planetary Instrument for X-Ray Lithochemistry (PIXL) and Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC).

On 10 September 2025, NASA reported a "potential biosignature" finding in Cheyava Falls: mudstones with organic carbon and with nodules less than 1 milimetre in size, and millimetre-scale boundaries, made by the meeting of different chemical reactions, which were heavy in ferrous iron phosphate and iron sulfide, as expected with minerals vivianite and greigite. That would mean low-temperature redox reactions after the rocks were deposited, between organics and Fe–S–P minerals. These textures and chemistries qualify as possible signs of life but require a closer look at the sample to be sure. On Earth, vivianite is frequently found in sediments, peat bogs, and around decaying organic matter. Similarly, certain forms of microbial life on Earth can produce greigite.

If confirmed to be a biosignature, that would mean that there was microbial life on Mars around 3.5 billion years ago. According to geologist Michael Tice:

The same organic materials can be made in non-biological ways which require "hot conditions" like volcanic activity; the place the rock was found suggests that it was underwater, and no past volcanic activity has been found in that area.

## Further research

NASA-ESA Mars Sample Return mission was designed to take the samples collected by _Perseverance_ and bring them to Earth. The mission was deemed "financially unsustainable" and was suggested to be cancelled by the Trump administration.

The article in _The Economist_ compared the sample return from Cheyava Falls with the return of a stranded astronaut from the book (and movie) _The Martian_.

According to the first author of the _Nature_ article, Joel Hurowitz, "labs on Earth could look for ways of achieving the same effects without either biology or high temperatures"; but even if it can be done, the result might fail the Knoll criterion: "to be evidence of life, an observation has to not just be explicable by biology; it has to be inexplicable without it".