The ExoMars Rover Instrument Suite
WISDOM - Water Ice and Subsurface Deposit Observation on Mars
The instrument suite of the ExoMars rover includes WISDOM (Water Ice Subsurface Deposit Observation on Mars), a radar that will provide a detailed view of the Red Planet's shallow subsurface structure by sounding the upper layers of its crust. Unlike traditional imaging systems or spectrometers, which are limited to studying the visible surface, this radar will access what lies beneath. WISDOM will provide the three-dimensional geological context of the terrain covered by the Rover. This additional perspective is vital for a better understanding of the planet's evolution, and the impact of its changing geology and climate on past and present habitability.
WISDOM will study the nature of the subsurface remotely, using radar pulses from a UHF ground penetrating radar, covering the frequency range from 500 MHz to 3 GHz, to map the subterranean layers. It will provide high-resolution measurements, with a vertical resolution of a few centimetres, down to a depth of 3 metres, complementing the 2-metre reach of the Rover's drill. The instrument can transmit and receive signals using two small antennas mounted on the back of the Rover. The WISDOM measurements will be used to identify optimal drilling sites by determining the nature, location and size of potential targets, and to ensure the safety of the drilling operations by minimising the likelihood of contact with potential hazards.
WISDOM's main science objectives are:
The profile of the subsurface geological structure will also complement the information from other instruments on the Rover, such as MicrOmega and the Raman spectrometer.
WISDOM's observations will also be combined with those produced by the Rover's panoramic camera, PanCam, and with analyses carried out on previously collected samples to construct three-dimensional maps of the subsurface.
A prototype, representative in terms of design, size, mass and power, has been developed. It has been tested successfully in a laboratory environment by sounding targets such as plates and spheres to validate its design specifications and verify its functionality.
Tests under quasi-realistic conditions have shown the instrument performance to be satisfactory. A field test was performed, on a glacier in the French Alps near Chamonix. The prototype carried out measurements down to more than 15 metres and detected structures with deep cracks. A series of tests in a variety of more complex environments and simulated Martian conditions began at the end of 2010, with a field test in Mount Etna, Italy, where the prototype successfully mapped the layers of the shallow subsurface.