In a paper published in February, scientists determined from models and data that the thickness of Martian cave ceilings required to protect you from radiation is not that much different whether you are on top of Olympus Mons (the Mount Everest of Mars), or at the bottom of Hellas Basin (Mars’ Death Valley).
From the paper’s conclusion:
Overall, the atmospheric thickness is not a dominant parameter for the required shielding. However, at a low-altitude crater where the surface pressure is above 1,000 Pa, the required subsurface shielding is about 10–20 cm [4 to 8 inches] less than at the top of high mountains where the pressure is below 100 Pa. Moreover, solar activities which determine the GCR flux arriving at Mars play an role. To reduce the annual effective dose to be below 100 mSv, the required shielding is 1.5–1.6 m [about 5 feet] during solar minimum and 0.9–1.1 m [a little more than 3 feet] during solar maximum. For a threshold of 50 mSv, the required shielding is 2.1–2.2 m [about 7 feet] during solar minimum and 1.7–1.9 m [about 6 feet] during solar maximum.
Essentially, what this research suggests is that to properly shield any underground facility, you need to cover it with at least seven feet of material, or be in a cave where the ceiling is that thick. It really doesn’t matter how much atmosphere is above you. Even at its thickest at the lowest elevation, Mars’ atmosphere doesn’t provide much protection.
Now available in hardback and paperback as well as ebook!
From the press release: In this ground-breaking new history of early America, historian Robert Zimmerman not only exposes the lie behind The New York Times 1619 Project that falsely claims slavery is central to the history of the United States, he also provides profound lessons about the nature of human societies, lessons important for Americans today as well as for all future settlers on Mars and elsewhere in space.
Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space
, is a riveting page-turning story that documents how slavery slowly became pervasive in the southern British colonies of North America, colonies founded by a people and culture that not only did not allow slavery but in every way were hostile to the practice.
does more however. In telling the tragic history of the Virginia colony and the rise of slavery there, Zimmerman lays out the proper path for creating healthy societies in places like the Moon and Mars.
“Zimmerman’s ground-breaking history provides every future generation the basic framework for establishing new societies on other worlds. We would be wise to heed what he says.” —Robert Zubrin, founder of founder of the Mars Society.
All editions are available at Amazon, Barnes & Noble, and all book vendors, with the ebook priced at $5.99 before discount. The ebook can also be purchased direct from my ebook publisher, ebookit, in which case you don't support the big tech companies and I get a bigger cut much sooner.
Autographed printed copies are also available at discount directly from me (hardback $24.95; paperback $14.95; Shipping cost for either: $5.00). Just email me at zimmerman @ nasw dot org.