Piled regolith is the usual first idea for a surface habitat cover. This page stops at the mass of that pile. Areal density is thickness times bulk density. You type both. The sheet does not store a measured density for a berm. A unit check, and only a unit check, is 100 cm times 1.5 g/cm3, which is 150 g/cm2, which is 1500 kg/m2. That 1.5 is not a Gale soil measurement.

Curiosity's Radiation Assessment Detector published a surface dose equivalent of 0.64 +/- 0.12 mSv/day at Gale during solar maximum, about August 2012 through June 2013, and an absorbed dose of 0.210 +/- 0.040 mGy/day. [1] The cruise measurement inside the spacecraft, before landing, was 1.84 +/- 0.30 mSv/day dose equivalent and 0.48 +/- 0.08 mGy/day absorbed. [2] Those rates are context. They are not an input to the column, and the column is not a dose.

Screen

Leave the density blank until you have one. The form will not invent it. The result is grams per square centimeter and kilograms per square meter. One gram per square centimeter is 10 kilograms per square meter. The form does not estimate a shielded dose, a career limit, or a safe thickness. Gale crater is the place the surface rate was measured. Design envelope is the index.

Column instrument

Screening sheet. Not for flight, medicine, or operations. The column is not a dose.

Areal density is thickness times density. 1 g/cm2 is 10 kg/m2. A 100 cm column at 1.5 g/cm3 is 150 g/cm2, and that 1.5 is a unit check, not a measured soil. Gale and cruise dose rates on this page are not inputs.

What the rates are not

The surface rate is one place, one solar-cycle window, and one instrument. It is not a planet-wide average and not a forecast for a later solar minimum, when galactic cosmic rays are higher. The cruise rate was inside a spacecraft, not in open space and not under a berm. Class D for any health reading: the number is published, and this sheet will not tell you what thickness makes it acceptable.

See also

References

  1. Hassler et al. Mars' surface radiation environment measured with the Mars Science Laboratory's Curiosity rover. Science 343 (2014), doi 10.1126/science.1244797. Gale, about August 2012 to June 2013. https://doi.org/10.1126/science.1244797
  2. Zeitlin et al. Measurements of energetic particle radiation in transit to Mars on the Mars Science Laboratory. Science 340 (2013), doi 10.1126/science.1235989. https://doi.org/10.1126/science.1235989

Categories

Engineering