Fact Check: Does Mars Photo Show Crater Full of Water Ice?

Photos of space can make people's imaginations run wild. Sometimes, they are used to spread false claims and misinformation. Mars has been at the center of some such claims over the years.

Newsweek has previously fact-checked an alleged "rainbow" on Mars that turned out to be a camera reflection, and also reported that a viral photo of Earth, Venus, and Jupiter in Mars' sky was actually a computer image. Now, another Mars image is circulating on social media.

The Claim

On February 13, Twitter account Everything Space, which has the handle @totalspace360, posted a photo of Mars' Korolev crater filled with white ice.

The tweet read: "ESA's Mars Express mission captured this unbelievable image of the Korolev crater filled with water ice!"

The post was retweeted more than 1,500 times and received more than 10,000 likes as of Wednesday morning ET.

Several users responded with skepticism, labeling the image "fake" or a "CGI" render.

The Facts

The image of Korolev crater was taken by the European Space Agency's (ESA) Mars Express orbiter, which launched back in 2003 and continues to operate today. ESA published the image in a press release in December, 2018, stating that it was captured using the orbiter's High Resolution Stereo Camera (HRSC).

The image is actually made up of five separate photo "strips" that were taken by the ESA spacecraft across separate orbits, and then merged together. This is a common way of taking photos in the field of astronomy, particularly where large objects like galaxies or nebulae are concerned.

So yes, it is a real image, but there is also a little bit of computer processing going on, according to Daniela Tirsch, a planetary geology expert at the German Aerospace Center (DLR), where camera technology for the Mars Express orbiter was developed.

She told Newsweek that the image shared on Twitter is essentially a real color image, combined with a digital elevation model generated by instruments aboard the Mars Express orbiter—similar to how Google Earth uses real images of our own planet combined with topography data. This is partly why the Korolev crater perhaps does not look 100 percent natural from the side-on angle.

The ESA image below uses the same data except without the digital elevation processing, and offers a more realistic-looking view of the same photo.

Korolev crater
A top-down view of the Korolev crater on Mars. ESA/DLR/FU Berlin

"The ice and the frost and everything you see is natural," Tirsch said. The only actual alterations to the image were color adjustments, since each of the five individual photos were taken at different times of the Martian year in different illumination conditions, according to the expert.

"The red tone of that image, if you were to be on Mars, might appear differently," she added.

So while it could be said that the image shared to Twitter is digitally-enhanced, it is still a real Mars photo.

The second claim to address is whether the crater is really full of water ice. This is also true.

Of the crater, ESA wrote in its 2018 press release: "It is an especially well-preserved example of a Martian crater and is filled not by snow but ice, with its centre hosting a mound of water ice some 1.8 kilometres thick all year round."

Scientists have known for several years that water ice exists on the Red Planet, with NASA stating in a 2019 article on its website that most of this ice is "locked away underground throughout the planet's mid-latitudes," and that astronauts could even use it as a resource.

Some water ice has also been observed on the surface before. ESA released an image of an unnamed Mars crater in the Vastitas Borealis plain back in 2005, seen here, that clearly shows "residual water ice" in the center.

The Ruling

Fact Check - True


ESA did release a real image of a Mars crater full of water ice, and this is the same image that has resurfaced on social media recently. The image may appear fake because of how it was processed.


Korolev crater
The ESA image of the Korolev crater on Mars filled with water ice, taken in 2018. The image is a mixture of real photo data and a digital terrain model. ESA/DLR/FU Berlin