The Rimfax georadar is one of the seven scientific instruments on the NASA rover "Perseverance," which landed on Mars in February 2021. The rover's task is to search for remnants of life and Rimfax will analyse the various geological layers in the ground to determine the best place to take samples.
The Mars 2020 rover is the fifth rover to launch to Mars and is also the most advanced. The rover is a rolling laboratory and it is also the first time a rover has a georadar attached. In spaceflight, a rover is a manned or unmanned motorized land vehicle used to explore alien celestial objects.
Mapping what is underground on Mars
With Rimfax, researchers will get a continuous picture of the geology along the rover's carriageway, which will provide important information about which areas are interesting to study further. An important goal is to find sedimentary layers where there may have been water and thus opportunities for life.
Rimfax can "see" beneath the surface by sending radio waves into the ground and by reflecting some of these waves. In this way, it can create a picture of what exists beneath the surface. What kind of substances are there? Is there moisture in the sand? And not least – are there signs of old life hiding?
The georadar will enable researchers to map structures and formations more than ten metres into the ground.
Strong Norwegian research communities are behind
Rimfax is entirely developed and produced by the Norwegian Defence Research Establishment (FFI) with support from Norwegian industry. When the US space agency NASA invited the research community to propose instruments for its Mars-2020 Mission, FFI proposed its georadar. Of the 58 proposals received, FFI's Rimfax became one of seven selected instruments.
NASA commissioned FFI to develop the georadar, and a strong Norwegian research community was selected for the NASA mission. Rimfax is operated from the Centre for Research-based Innovation, CENSSS, at the University of Oslo with researchers from the University of Oslo, the University of California, Los Angeles (UCLA), the University of Arizona, and Cornell University.
Rimfax consists of an antenna and an electronics box. The gold-plated box contains the technology that makes it possible to read more about the planet's interior. The rover and all mounted equipment must withstand night temperatures from minus 135 degrees Celsius to Mars days with 20 degrees Celsius. Rimfax must also be able to withstand 100 degrees Celsius because it sits close to the nuclear reactor of the rover.
The georadar itself is quite small and weighs only 2.5 kilograms. Georadars can also be used for archaeological surveys and for research on avalanches.
Georadars with many applications
FFI has worked with similar radars before, and initially developed radars of this kind to make it possible for the Armed Forces to "see" through walls and into the ground. The use would be, for example, to find buried mines. The same type of technology is used in archaeology and to research avalanches. FFI has also studied the use of this type of ultra-wideband radar in a medical context, for example to image the heart.
Rimfax stands for Radar Imager for Mars' Subsurface Experiment. The name also plays on Norse mythology: Rimfakse is the horse that the night rides across the sky. The morning dew came dripping from Rimfakse's bissel and the name translates as rhyme from the mule.
Sources:
Norwegian Romsenter
FFI
Nysgjerrigper
Titan
Forskning.no