“This would be the first time any of the children saw the surface. The colonists had built underground, using existing caves and lava tubes where possible, building and burying structures where necessary. This was to protect themselves from solar and cosmic radiation. On Earth, the atmosphere and magnetic field serve this purpose. But Mars has little of either, so dirt and rock filled the role.”
– from Scratching the Surface: Generation Mars, Prelude
A new paper explores lava tubes in the Hellas Planitia as possible habitats for humans.
A trip to Mars using current propulsion technology takes several months. During that time, astronauts will be exposed to solar and cosmic radiation. In Iowa, a group of undergrads is working the problem.
Hibernation during space travel is a common sci-fi trope, but I wasn’t aware anyone was actively working on it. What I find particularly compelling here is that hibernation could have positive effects on bone density change as well as helping mitigate the effects of radiation exposure.
Another thought occurs to me, though it is not mentioned here. Keeping the travelers contained in a small area opens up options for radiation shielding that might otherwise be prohibitive. What about sleeving the hibernation quarters in water, for instance? If that water could be mined from the Moon, the cost of lifting it for use in the craft could be acceptable.
Circling back to my note on solar wind and the Martian atmosphere.
In the note, I described how the solar wind interacts with the ionosphere of Mars to create an induced magnetosphere. Recent data from ESA’s Mars Express mission suggests that this induced magnetosphere actually protects the Martian atmosphere from the ion loss expected to be caused by that same solar wind. Thus, the long held idea that the solar wind blew away Mars’ atmosphere is now in question.
The article below outlines an alternative hypothesis. Rather than losing atmosphere to the solar wind, maybe Mars can’t hold onto one because its gravity is just too weak.
Here’s a fun paper that analyzes the radiation exposure of characters in The Martian. The TL;DR is that Mark Watney would have fared better than his crewmates in the Hermes.
Mars, with its thin atmosphere and lack of magnetosphere, doesn’t offer as much protection as Earth, but it’s better than nothing.