The Radar Imager for Mars' Subsurface Experiment (RIMFAX) uses radar waves to probe the ground under the rover. It is located at the lower rear of the Mars 2020 rover’s “body."  The radar signals returned to RIMFAX look a little like sonograms that show structures under the Martian surface. The radar signals change depending on what materials are present underground, such as ice, rock, sand, and liquid water.
image of RIMFAX instrument
decorative gear graphic

Tech Specs

  • MAIN JOB:To see geologic features under the surface with ground-penetrating radar
  • LOCATION:The radar antenna is on the lower rear of the rover
  • MASS:Less than 6.6 pounds
    (3 kilograms)

  • POWER:5 to 10 watts
  • VOLUME:7 by 4.7 by 2.4 inches
    (196 x 120 x 66 millimeters)
  • DATA RETURN:5 to 10 kilobytes per sounding location
  • FREQUENCY RANGE:150 to 1200 megahertz
  • VERTICAL RESOLUTION:As small as about 3 to 12 inches thick (15 to 30 centimeters) thick.
  • PENETRATION DEPTH:Greater than 30 feet (10 meters) deep depending on materials.
  • MEASUREMENT INTERVAL:About every 4 inches (10 centimeters) along the rover track
image of Svein-Erik Hamran
Svein-Erik Hamran
Principal Investigator
Norwegian Defence Research Establishment
Kjeller, Norway

"No one knows what lies beneath the surface of Mars. Now, we'll finally be able to see what's there."

-- Svein-Erik Hamran
NASA radar studies melting ice in Antarctica on Earth. Credit: NASA/Operation Ice Bridge

Did You Know?

Scientists widely use radar to look for things underground on Earth. They use it to study Mars-like glacial regions in the Arctic and Antarctic. Ground-penetrating radar helps us locate land mines; spot underground cables, wires and pipes; and reveal ancient human artifacts and even buried treasure! On Mars, the "buried treasure" may be water ice, which helps scientists understand the possibilities for Martian life and also identifies natural resources for future human explorers.
Five Things To Know
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Just like explorers probing below Earth's crust, scientists can use this radar instrument to "see" the unexplored world that lies beneath Mars' surface.
detects water and ice
RIMFAX can detect ice, water or salty brines of more than
30 feet (10 meters)
beneath the surface
of Mars!
is like radars on earth
Engineers based the RIMFAX design on ground-penetrating radar used on Earth to probe the underground layers of rock and ice in the Arctic and Antarctic.
is a first for Mars
It is the first radar tool sent to the surface of Mars on a NASA mission.
sees structural details
RIMFAX reveals underground Mars in detail. It gives us a new view into Mars' ancient past, when different fluids and rocks settled into layers now buried.

RIMFAX: The Story Behind the Name

The Story Behind the Name: RIMFAX

RIMFAX takes its name from Hrímfaxi, the horse in Norse mythology that faithfully brings the night (Nótt).  Nótt is the grandmother of Thor, famed god of thunder.

Hrímfaxi means “the one with rime (frost) in its mane.”  Its partner is Skinfaxi, the horse that brings the day (Dagr).  Skinfaxi means “the one with the shining mane.”

Rime on twigs in winter at Yellowstone National Park
You can see how the formation of rime in winter may have inspired the myth of Hrímfaxi's frosty mane. Credit: NPS