As NASA gets set to send a rover to Mars next year, a newly released picture of what appears to be an "underground cavern" on the Red Planet is raising questions.

"The hole, shown in representative color, appears to be an opening to an underground cavern, partly illuminated on the image right," NASA wrote in a blog post. "Analysis of this and follow-up images revealed the opening to be about 35 meters across, while the interior shadow angle indicates that the underlying cavern is roughly 20 meters deep."

The crater, located on the Pavonis Mons volcano, was first spotted when the Mars Reconnaissance Orbiter took an image of it in 2011.

MYSTERIOUS 15M-YEAR-OLD CRATER ON EARTH COULD UNLOCK SECRETS ABOUT MARS

Researchers don't yet fully know the reason for the crater, adding it "remains a topic of speculation," nor do they know the full extent of the cavern.

However, it remains of interest because they are "relatively good candidates to contain Martian life," and are "prime targets" for future exploration, the authors, Robert Nemiroff and Jerry Bonnell, wrote.

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The Mars 2020 rover, which is slated to launch July 17, will attempt to detect if there is any fossilized evidence of extraterrestrial beings, in addition to other tasks.

Upon its expected arrival on the Martian surface on Feb. 18, 2021, it will join the still functioning Curiosity rover and the now-deceased Opportunity rover on the Red Planet. Unlike Curiosity or Opportunity, this rover will carry the "first helicopter that will fly on another planet," NASA added.

NASA’s long-term goal is to send a manned mission to Mars in the 2030s.

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