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An artist's concept of NASA’s Mars Reconnaissance Orbiter, which has been orbiting the Red Planet since 2006. The antenna is part of SHARAD, a radar that peers below the Martian surface. Image Credit: NASA/JPL-Caltech |
A new study published in
Geophysical Research Letters casts doubt on a 2018 discovery of a briny lake potentially lurking beneath Mars’ south polar cap.
SHARAD, the Shallow Radar sounder on NASA’s Mars Reconnaissance Orbiter (MRO), performed a maneuver that allowed it to peer deeper beneath the polar ice than ever before. It recorded only a faint signal where MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding), the low-frequency radar on the European Space Agency’s Mars Express spacecraft, found a highly radar-reflective surface under the ice in 2018, which that team interpreted to be due to the presence of liquid water.
“The existence of liquid water under the south pole is really compelling and exciting, but if it is there, SHARAD should also see a very bright reflectance spot, and we don’t,” said study lead author Gareth Morgan, a SHARAD co-investigator and Planetary Science Institute senior scientist.