SHARAD (Shallow Radar) looks for liquid or frozen water in the first few hundreds of feet (up to 1 kilometer) of Mars' crust.
Mars Reconnaissance Orbiter's Radar, Top View (Artist's Concept)
This image is an artist's concept of a view looking down on NASA's Mars Reconnaissance Orbiter. The spacecraft is pictured using its Shallow Subsurface Radar instrument (SHARAD) to "look" under the surface of Mars.
SHARAD probes the subsurface using radar waves within a 15- to 25-megahertz frequency band to get the desired, high-depth resolution.
The radar wave return, which is captured by the SHARAD antenna, is sensitive to changes in the electrical reflection characteristics of rock, sand, and any water that may be present in the surface and subsurface. Water, like high-density rock, is highly conducting, and has a very strong radar return. Changes in the reflection characteristics of the subsurface, caused by layers deposited by geological processes in the ancient history of Mars, are also visible.
The instrument has a horizontal resolution of between 0.3 and 3 kilometers (between two-tenths of a mile and almost 2 miles) and a vertical resolution of 15 meters (about 50 feet) in free space, which translates into better than 10 meters in the martian subsurface. Subsurface features on the order of these dimensions are observable.
SHARAD was provided by the Italian Space Agency (ASI). The Principal Investigator (lead scientist) is Roberto Seu.
US investigators selected to participate are: