A few months from now, a NASA spacecraft called the Mars Reconnaissance Orbiter (MRO) will begin its 20th year of observing the Red Planet from above. And, like most 20-year-olds on Earth, MRO's camera roll is absolutely packed.
According to NASA, MRO has just taken its 100,000th photo of the Martian surface using its HiRISE camera. Put another way, that's an average of 5,000 photos a year, 417 photos a month, or about 14 a day every day since March 2006.
The new milestone image, snapped on Oct. 7, shows a shadowy wasteland of mesas, craters and dunes known as Syrtis Major. This region is just southeast of Jezero Crater, the ancient lakebed where NASA's Perseverance rover is hunting for evidence of life, and appears as an enormous dark spot when seen from afar by space telescopes like Hubble.
MRO has observed the region many times before, and has previously turned up evidence that the sand dunes there are slowly migrating across the planet's surface.
"HiRISE hasn't just discovered how different the Martian surface is from Earth, it's also shown us how that surface changes over time," Leslie Tamppari MRO's deputy project scientist at NASA's Jet Propulsion Laboratory, said in a statement. "We've seen dune fields marching along with the wind and avalanches careening down steep slopes."
Studying how the Red Planet changes over time will help demystify the forces that govern it, and help reveal whether it was ever a lush waterworld like Earth. Launched from Florida on Aug. 12, 2005, and inserted into Mars orbit on March 10, 2006, the MRO will continue its mission to photograph the planet as long as it's able.
Occasionally, MRO does take a break from its primary mission to gaze off into space. In October, the satellite looked skyward to snap a shot of the interstellar comet 3I/ATLAS as it passed about 19 million miles (30 million kilometers) from the spacecraft — significantly closer that the comet got to Earth at its closest point on Dec. 19.
While MRO wasn't designed to observe small, fast-moving objects at such great distances, it nevertheless provided early confirmation that 3I/ATLAS showed the telltale characteristics of a natural comet, including a small nucleus enshrouded in a bright coma of gas and dust.
