While asking questions about habitability on Mars, one thing that scientists also need to consider is whether it’s safe enough for humans to even do exploration there. Radiation is definitely a big factor — in a press conference yesterday (Dec. 9) for the American Geophysical Union’s conference, scientists said the environment is unlike anything we are used to naturally on Earth.
Radiation on Mars comes from two sources: galactic cosmic rays (over the long term) and solar energetic particles (in short bursts of activity when the sun gets super-active). Of note, the sun has had a muted peak to its solar cycle, so that’s affecting the expected amount of particles on Mars. But the Mars Curiosity rover, in its first 300 Earth days of roaming, has plenty of data on galactic cosmic rays.
On the Martian surface, the average dose is about 0.67 millisieverts (mSv) per day, at least between the measurement period of August 2012 and June 2013. The journey to Mars had a dose of 1.8 mSv per day inside the spaceship. So what does that means for NASA’s human health consideration concerns?
With a 500-day trip on the surface and the journey to and from Mars (which would take 180 days each way), NASA is saying the total dosage for the mission would be about 1 Sv. Population studies over the long term have shown that increases the fatal cancer risk by 5%. Current NASA guidelines for low-Earth orbit don’t allow for a more than 3% increase, but 1 Sv is within the guidelines for several other space agencies.
But don’t rule out the trip to Mars yet, NASA states: “[NASA] does not currently have a limit for deep space missions, and is working with the National Academies Institute of Medicine to determine appropriate limits for deep space missions, such as a mission to Mars in the 2030s.”
Besides, other entities are thinking about going, such as Mars One.
Read more about the radiation findings in this Dec. 9 article on Science. The research was led by Don Hassler, a Southwest Research Institute program director and principal investigator of Curiosity’s radiation assessment detector (RAD).
Source: Southwest Research Institute