Presentation Information
[PPS07-P01]Searching for Surface Changes on Phobos over Decades
*Ronald Terik Daly1, Oliver S. Barnouin1, Carolyn M. Ernst1, R. Josh Steele1 (1.Johns Hopkins University Applied Physics Laboratory)
Keywords:
MMX,Phobos,Deimos,Surface Change
The moons of Mars hold critical clues to solar system formation and evolution. Later this year, the Martian Moons eXploration (MMX) mission will launch to investigate those clues. After conducting a detailed study of Phobos, the MMX spacecraft will land, collect samples, and—for the first time ever—return Phobos samples to Earth. MMX will also perform multiple flybys of Deimos.
MMX joins an armada of robotic spacecraft have imaged Phobos and Deimos, including Viking 1, Viking 2, Phobos 2, Mars Global Surveyor (MGS), Mars Express (MEx), and the Mars Reconnaissance Orbiter (MRO). Deimos has also been imaged by the Hope and Hera missions. Once MMX begins collecting images of Phobos and Deimos, we will have images of the martian moons that span ~50 years. This timespan means that we should be able to identify surface changes on Phobos and Deimos by comparing MMX images with those from previous missions, thereby assessing how Phobos and Deimos have changed through time. Given the impact crater production function for Mars and its surface area, Phobos should have one or two impact craters large enough to be detectable (>6 m in diameter) in MMX images compared to images from historical missions. The number of detectable surface changes on Phobos is likely much higher: One lunar study detected >200 times more changes in surface reflectance than new impact craters (Speyerer et al., 2016, doi: 10.1038/nature19829.).
We will search for areas of recent surface change using temporal pairs—images of a given region with similar pixel scales and lighting conditions—and ratioing images taken by MMX to those taken by previous spacecraft. We will build up a catalog of possible surface changes and classify them, similar to studies of surface changes on the Moon and Mars. Lastly, we will attempt to discern the cause of each change (e.g., is there a topographic signature, such as a crater; is it on a slope? etc.), look for patterns, and put the changes in geologic context. We plan to do this work during the primary flight phase of MMX so the mission has the option to sample or rove near areas that have changed in recent decades.
MMX joins an armada of robotic spacecraft have imaged Phobos and Deimos, including Viking 1, Viking 2, Phobos 2, Mars Global Surveyor (MGS), Mars Express (MEx), and the Mars Reconnaissance Orbiter (MRO). Deimos has also been imaged by the Hope and Hera missions. Once MMX begins collecting images of Phobos and Deimos, we will have images of the martian moons that span ~50 years. This timespan means that we should be able to identify surface changes on Phobos and Deimos by comparing MMX images with those from previous missions, thereby assessing how Phobos and Deimos have changed through time. Given the impact crater production function for Mars and its surface area, Phobos should have one or two impact craters large enough to be detectable (>6 m in diameter) in MMX images compared to images from historical missions. The number of detectable surface changes on Phobos is likely much higher: One lunar study detected >200 times more changes in surface reflectance than new impact craters (Speyerer et al., 2016, doi: 10.1038/nature19829.).
We will search for areas of recent surface change using temporal pairs—images of a given region with similar pixel scales and lighting conditions—and ratioing images taken by MMX to those taken by previous spacecraft. We will build up a catalog of possible surface changes and classify them, similar to studies of surface changes on the Moon and Mars. Lastly, we will attempt to discern the cause of each change (e.g., is there a topographic signature, such as a crater; is it on a slope? etc.), look for patterns, and put the changes in geologic context. We plan to do this work during the primary flight phase of MMX so the mission has the option to sample or rove near areas that have changed in recent decades.