12.13.2016 Now and Long Ago at Gale Crater, Mars
12.13.2016 Where's Boron? Mars Rover Detects It
10.03.2016 Curiosity Self-Portrait at 'Murray Buttes'
10.03.2016 Butte 'M9a' in 'Murray Buttes' on Mars
09.19.2016 Ribbon Cutting
09.09.2016 Farewell to Murray Buttes (Image 5)
09.09.2016 Farewell to Murray Buttes (Image 4)
09.09.2016 Farewell to Murray Buttes (Image 3)
09.09.2016 Farewell to Murray Buttes (Image 2)
09.09.2016 Farewell to Murray Buttes (Image 1)
08.26.2016 Out-of-this-World Records
03.30.2016 Erisa Hines
03.30.2016 Buzz Aldrin
02.12.2016 Women in Science
02.09.2016 Adam Steltzner, a JPL engineer
01.27.2016 Night Close-up of Martian Sand Grains
01.27.2016 Curiosity Self-Portrait at Martian Sand Dune
12.17.2015 Alteration Effects at Gale and Gusev Craters
12.17.2015 Full-Circle View Near 'Marias Pass' on Mars
12.11.2015 Surface Close-up of a Martian Sand Dune
12.11.2015 Martian Sand Disturbed by Rover Wheel
11.24.2015 Carbon Exchange and Loss Processes on Mars
11.17.2015 Chemical Laptop 1
Curiosity Blasts Ground with NeutronsNASA's Curiosity rover pinged the ground with neutrons for the first time, a process called active neutron sounding, on Aug. 17, 2012. The instrument involved, called the Dynamic Albedo of Neutrons, or DAN, measures the amount of hydrogen -- an indicator of water -- in soil by observing the degree to which neutrons are scattered.
The red time profile shows neutrons that were emitted from the ground below Curiosity after the instrument's pulsing neutron generator hit the ground with pulses of neutrons having energies of 14 megaelectron volts. The blue line shows a pre-launch test of the instrument for comparison.
These data provide information about the content of water at the Curiosity landing site, and show that the instrument is in perfect shape for the first use of the neutron sounding technique in its interplanetary exploration. Later, when Curiosity is on the move, variations of the height and duration of this profile will indicate changes in the water content of the soil down to about 3.3 feet (one meter) below the surface.
The most likely hydrogen in the ground of Gale Crater is in hydrated minerals. These are minerals with water molecules or hydroxyl ions bound into the crystalline structure of the mineral. They can tenaciously retain water from a wetter past after all free water has gone.
Image Credit: NASA/JPL-Caltech/Russian Space Research Institute