【Sisters Slave (2019)】

The Sisters Slave (2019)Mars Reconnaissance Orbiter (MRO) recently passed its 15th anniversary leaving Earth behind to observe the red planet, and NASA is celebrating by recapping some of the robot’s best images. You’ve probably seen some of them pop up over the last few years but maybe never stopped to appreciate how much this mission has contributed to our understanding of Mars. Well, here’s an opportunity to soak it all in. 

The MRO launched in 2005 aboard an Atlas V rocket, reaching Mars several months later. NASA designed the probe to last for about five years, but here we are significantly past that, and the MRO is still going strong. Most of the images we’ve seen from the MRO comes from the orbiter’s High Resolution Imaging Science Experiment (HiRISE) camera, which is a 0.5-meter (1 ft 8 in) reflecting telescope. That’s the largest ever carried into deep space, and it shows. The images the MRO has returned of Mars are startlingly clear, thanks in part to the planet’s thin atmosphere. 

This mission regularly reminds us that Mars has a surprisingly dynamic surface for an uninhabited planet with no appreciable geological activity. For example, in 2012 the probe spotted the amazing dust devil below. Judging from its shadow, NASA says the twister was half a mile tall. 

A year later in 2013, the MRO spied a feature on the red planet: a crater (below). Yes, Mars has a lot of those, but this was new. Between 2010 and 2012, an object smacked into the surface, leaving a 100-foot (30-meter) pockmark. NASA says the impact tossed ejecta far as 9.3 miles (15 kilometers).

The MRO also pays attention to what’s in space around Mars. In 2008, the probe swung past the Martian moon Phobos, taking the clearest images of the tiny moonlet ever. The origin of Phobos is unclear, but scientists believe it’s either a captured asteroid or a piece of Mars blasted into orbit by an ancient impact. 

More recently in 2019, the MRO returned images of the planet’s northern polar region. That puff in the upper left corner of the below image is an avalanche happening before your eyes on another planet. NASA says thawing seasonal ice destabilized a cliff and triggered the rock slide. 

NASA has plenty more images from MRO for you to enjoy. You can even suggest new observation targets for the mission through the University of Arizona.