In 2020, NASA’s Mars rover Perseverance landed on the surface of Mars.
The rover is searching Mars for signs of microbes that may have once lived there. The goal is to find out whether Mars could have once been habitable for living organisms and whether the components necessary for life still exist beneath the planet’s surface.
The Perseverance rover is state-of-the-art technology and equipped with a variety of research instruments, including the RIMFAX georadar.
RIMFAX is a GPR that can detect and study layers of sediment, rock, ice, fresh water, or salt water buried in the Martian soil. These layers contain information about the ancient climate conditions on Mars.
Different materials (e.g., rock, clay, water, ice, sand) reflect, absorb, or scatter radar pulses in different ways. GPR RIMFAX can be used to obtain information about layers composed of different materials and to create a structural model of the soil layers. The data obtained can be linked to information collected by other technologies on the Mars rover, providing a comprehensive picture of Mars.
GPR RIMFAX uses frequency-modulated technology and its antennas operate in the 150 MHz to 1200 MHz range. This means that the wavelength of the RIMFAX radar ranges from millimeters to several meters. Depending on what the RIMFAX team wants to investigate, the frequency of the radar waves can be adjusted to lower (up to 150 MHz) or higher (up to 1200 MHz) frequencies. Lower frequency radio waves penetrate deeper into the Martian soil, but the resolution of the images created from the collected data is lower. Higher frequencies provide better resolution, but the radar waves cannot penetrate as deeply.
RIMFAX GPR rover Perseverance
The RIMFAX research team can use the changing wave frequency to “tune” or “focus” the device according to the depth of interest and the size of the object. Depending on the depth to be explored and the size of the objects to be “seen” in the radar data, the RIMFAX research team can choose between five different operating modes. RIMFAX’s vertical resolution (15–30 centimeters) is sufficient to see and distinguish different soil layers. When the rover is moving, RIMFAX sends a GPR pulse into the Martian soil and collects data from it every 10 centimeters. Depending on the properties of the materials in the soil, RIMFAX can “see” to a depth of more than 10 meters.
Info source: NASA