The close-up image, captured by the MRO’s High Resolution Imaging Science Experiment (HiRISE) camera on March 30, 2015, shows an impact crater in almost touchable detail. The crystal-clear image can be deceptive when it comes to the crater’s size. Although it might appear larger, in fact the crater is only about one kilometer across, just over half the diameter of Earth’s most celebrated meteor crater, the Winslow Crater in Northern Arizona.
The crater’s sharp rim and well-preserved ejecta, spread over the surrounding plain, can clearly be seen. NASA describes the crater as being “relatively recent” in geological terms but in human timescales, it’s ancient.
In the image, the crater is characterized by steep inner slopes carved by gullies and what NASA describes as “recurring slope lineae on the equator-facing slopes.” More recent craters, such as this example in the Sirenum Fossae, often have steep active slopes. The University of Arizona, which operates HiRISE, will continue monitoring this crater to check on any changes over time.
The Sirenum Fossae region of Mars lies roughly one-third of the way south of the Martian equator at 161° west. This region consists of a low lying trough or ditch, scarring 2,735 kilometers (1,700 miles) across the Martian landscape. The Sirenum Fossae is believed to have been formed as a result of movement along a pair of geological faults that caused the center section to drop down.
The HiRISE camera is just one of a number of cameras and spectrometers on board NASA’s MRO which has been conducting reconnaissance of the Red Planet since late 2006. The MRO’s original two year primary mission has been extended on a number of occasions and is now into its tenth year. Onboard instruments send back a range of data analyzing the landforms, geology, polar caps and other Martian features. The mission is the forerunner to future missions that will monitor weather and surface conditions on Mars, as well as picking out potential future landing sites. The long term aim is to gather as much data as possible with one eye to a future manned mission to the Red Planet.
To date, the MRO has sent back more data on Mars than all previous interplanetary surveillance missions combined.
