Lava tubes

“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.

Rust as radiation shielding

About that radiation… what about rust as a shield?
The research focused on shielding for electronics, but could this scale? Imagine our Mars transit ships being the same color as the planet itself, coated in a layer of rust for protection.

The perennial question: Moon or Mars?

We don’t need to go to the Moon in order to go to Mars. This doesn’t mean we shouldn’t go to the Moon. It’s just not a prerequisite.

I love this quote from John Grunsfeld, when asked about the radiation risk of a Mars trip: “How does that compare to the risk of blowing up on the launchpad or on ascent; getting hit by a meteor, asteroid, debris, some kind of space junk on the way there; burning up in the Mars atmosphere; burning up in the Earth’s atmosphere on the way back; or missing the Earth? You add up all those risks, and the [risk of radiation exposure] is kind of just another one.”


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.

Solar Wind (Slight Return)

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.