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
Longer-Term Radiation Variations at Gale CraterThis graphic shows the variation of radiation dose measured by the Radiation Assessment Detector on NASA's Curiosity rover over about 50 sols, or Martian days, on Mars. (On Earth, Sol 10 was Aug. 15 and Sol 60 was Oct. 6, 2012.) The dose rate of charged particles was measured using silicon detectors and is shown in black. The total dose rate (from both charged particles and neutral particles) was measured using a plastic scintillator and is shown in red.
The variations occur each day and also on longer timescales. The daily variations are driven by the thickness of the Mars atmosphere. The longer-term variations appear to be driven by the structure of the gas and plasma in the interplanetary space near Mars. This structure, called the heliosphere, is magnetically tied to the sun, and rotates together with the sun over a period of about 27 days. The density of this heliospheric structure, as seen at Mars, varies with a roughly 27-day period, and provides "shielding" from galactic cosmic rays outside the solar system, in much the same way that the Mars atmosphere provides shielding.
The graphic has a few gaps for software uploads and other mission priorities. Radiation dose is given in arbitrary units to reflect the magnitude of the variations. Calibration of the absolute dose levels is ongoing.
Image Credit: NASA/JPL-Caltech/SwRI