Why does NASA's Curiosity rover have a 'lucky penny' on Mars? | Space photo of the day for May 6, 2026

A penny on Mars, captured in a photo by NASA's Curiosity rover. (Image credit: NASA/JPL-Caltech/MSSS)

Can you imagine picking up a lucky penny on Mars?

What is it?

NASA's Curiosity rover captured a surprisingly Earthly image on the surface of Mars. With its Mars Hand Lens Imager (MHLI), the rover snapped a close-up image of a penny. (To clarify: The penny wasn't found there by accident; it traveled to Mars with the rover.)

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This image was captured on Oct. 2, 2013 on the 411th sol, or Mars day, of the Curiosity rover's mission on the planet. On the penny's surface, reddish Martian dust has collected over the 14 months that the mission had already been on Mars by that point.

Why is it incredible?

It's neat to see a penny on another planet. It's a (now endangered) relic from our own world minted over 100 years ago, in 1909, feeling the Martian wind dragging dusty debris across its surface millions of miles away.

But this penny serves a surprisingly important purpose: scale. In photographs, it can sometimes be difficult to tell how big or small something is without an object of known size, like a penny or a banana, in frame for scale.

"When a geologist takes pictures of rock outcrops she is studying, she wants an object of known scale in the photographs," MAHLI Principal Investigator Ken Edgett said in a statement in which NASA refers to the coin as a "lucky penny on Mars."

"If it is a whole cliff face, she'll ask a person to stand in the shot. If it is a view from a meter or so away, she might use a rock hammer. If it is a close-up, as the MAHLI can take, she might pull something small out of her pocket. Like a penny."

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Chelsea Gohd
Content Manager

Chelsea Gohd served as a Senior Writer for Space.com from 2018 to 2022 before returning in 2026, covering everything from climate change to planetary science and human spaceflight in both articles and on-camera in videos. With a M.S. in Biology, Chelsea has written and worked for institutions including NASA JPL, the American Museum of Natural History, Scientific American, Discover Magazine Blog, Astronomy Magazine, and Live Science. When not writing, editing or filming something space-y, Gohd is writing music and performing as Foxanne, even launching a song to space in 2021 with Inspiration4. You can follow her online @chelsea.gohd and @foxanne.music