A friend joked the other day that it might be time to put up a traffic light on Mars. There are currently three active rovers on the surface. Two belong to the U.S. — Curiosity, which has been sniffing around since August 2012, and Perseverance (Feb. 2021). China became the second nation in history to successfully land a rover on Mars on May 14th. Named Zhurong, for the Chinese god of fire, it returned its first photos to Earth this week.
Zhurong rests atop the Tianwen-1 lander. The rover-lander platform combination is similar to that used by the Yutu-1 and Yutu-2 lunar missions. In each, a ramp extends from the lander which the rover uses to wheel down to the surface. Since the China National Space Administration (CNSA) keeps its cards close it's hard to know exactly when it plans to move Zhurong, but the ramp has been deployed, so it should be soon.
As was the case with NASA's Opportunity and Spirit rovers, China's primary mission will last 90 days. Spirit continued operating for another 6 years, while Opportunity worked for nearly 15 years before a global dust storm finally put it to rest. Hopefully, Zhurong will have similar longevity. Like those rovers, it's powered by solar panels which convert sunlight into electricity. This is different from the current NASA rovers which transform the heat generated by the radioactive decay of plutonium into electrical power.
Tianwen 1 landed in Utopia Planitia, a vast, icy plain in the planet's northern hemisphere. With an expanse of some 2,050 miles (3,300 kilometers) the region is thought be an impact basin from an asteroid strike in the distant past. The lander has taken up residence a little more than 1,000 miles (1,600 km) from NASA's Viking 2 lander, which arrived in Utopia 45 years ago in 1976.
Once all its instruments are checked out Zhurong will take photos, study the local climate, measure magnetic fields and determine the mineral composition of rocks with its laser spectrometer. It's also equipped with ground-penetrating radar to search for subsurface water ice in conjunction with the Tianwen-1 orbiter, which will do the same from up high.
Back in 2016, NASA's Mars Reconnaissance Orbiter discovered a patch of underground ice in Utopia about the size of the state of New Mexico that would fill Lake Superior to the brim if you could melt it all. Water or ice evaporates rapidly at the Martian surface. Viking recorded frequent frosts and ice fog that soon sublimated (turned to vapor) in sunlight during its stay. The Utopian deposit persists because it's protected by a layer of soil from 3 to 33 feet (1 to 10 meters) thick.
Mars can be tantalizingly Earth-like with its clouds, glaciers, layered sedimentary rocks and now-desiccated lakes and rivers. In a recent paper, scientist and lead author David Horvath of the Planetary Science Institute, offers evidence that volcanic eruptions on Mars could have occurred as recently as 50,000 years ago.
Most Martian volcanism occurred between 3 and 4 billion years ago but using data from satellites orbiting Mars, the research team found evidence of an eruption in the Elysium Planitia region that would be the youngest known volcanic eruption on the Red Planet.
"If we were to compress Mars geologic history into a single day, this would have occurred in the very last second," said Horvath.
The feature is a peculiar-looking dark deposit covering an area slightly larger than Washington D.C. similar to dark spots on the moon and Mercury that are thought to be caused by volcanic eruptions. It overlies older lava flows and appears to be a fresh deposit of ash and rock rich in pyroxene, a mineral often found in volcanic rocks. NASA's Mars InSight lander detected two Marsquakes from the region, but it's not known if they're directly related to the fissure and dark patch.
Horvath also raised the intriguing possibility that magma rising from the eruption could have melted ice in the region, providing favorable conditions for life fairly recently.
"Astro" Bob King is a freelance writer for the Duluth News Tribune. Read more of his work at duluthnewstribune.com/astrobob.