May 31 (UPI) -- NASA has released a new image from its Mars Reconnaissance Orbiter that shows the red planet's Hale Crater -- a large impact crater with more than 62 miles of intriguing physical features.
The crater contains active gullies, extensive icy ejecta flows and active recurring slope lineae, which are long marks that are dark or bright.
NASA has released images of these recurring slope lineae within the crater before. In 2015, the agency suspected that the streaks, which appeared to flow downhill, were caused by contemporary flowing water. Planetary scientists had recently discovered hydrated salts -- trace amounts of water mixed with heavy doses of salts -- on the slopes of the crater, which the agency said at the time confirmed the theory.
Similar features on Earth are caused by flowing water. Scientists theorized there could be enough liquid water on the Martian surface to support microbial life.
Then last year, new research argued that the streaks were not caused by underground supplies of liquid water. A new study suggested the streaks could be flows of sand and dust. The new understanding supported evidence that the contemporary planet is very dry, scientists said.
That theory doesn't completely debunk the suspicion that the red planet contains enough water to support life. Earlier this year, NASA scientists discovered layers of water ice buried only feet beneath Mars' surface -- just not within the Hale Crater.
Scientists have theorized for more than a decade that reserves of water ice are locked underground on Mars. Scans of the planet have revealed signs of shallow ground ice at high latitudes and a mission even dug up water ice near the Martian north pole.
In 2016, the Mars Reconnaissance Orbiter found a buried sheet of ice at mid-latitudes that hold about as much water as Lake Superior.
These discoveries could influence how future astronauts who travel to Mars would harvest their water, scientists say. Human missions to the red planet would likely rely on extracting water from the local environment. They would either bake it out of hydrated minerals or mine it from ice deposits.
That would mean either breaking it down from the hydrated salts -- which may or may not lie within the Hale Crater -- or digging through a few feet of rock to access the ice sheets.