Investigating Mars: Ascraeus Mons

This image shows part of the complex caldera at the summit of the volcano. Calderas are found at the tops of volcanoes and are the source region for magma that rises from an underground lava source to erupt at the surface. Volcanoes are formed by repeated flows from the central caldera. The final eruptions can pool within the summit caldera, leaving a flat surface as they cool. Calderas are also a location of collapse, creating rings of tectonic faults that form the caldera rim. Ascraeus Mons has several caldera features at its summit. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 17440 Latitude: 11.128 Longitude: 255.731 Instrument: VIS Captured: 2005-11-19 08:59 https://photojournal.jpl.nasa.gov/catalog/PIA21822