Much of the discussion about travelling to Mars and the first person to step out onto the red planet has focused on the technological challenges of space flight. What has been missing from a large amount of the discourse is whether people can survive on Mars? How well will we physiologically adapt?
Perhaps the biggest safety obstacle is the hazard posed by particle radiation from the Sun, distant stars and galaxies. Can this be overcome, and if so, for how long?
This leads to the important and emerging question of space medicine: Would particle radiation pose too grave a threat to human life throughout a round trip to the red planet? As a supplementary questions, researchers are also considering if very timing of a mission to Mars help shield astronauts and the spacecraft from the radiation?
These questions have been posed by researchers from University of California – Los Angeles. The inquiry has established that people should be able to safely travel to and from Mars. This is provided that the spacecraft has sufficient shielding and the round trip is shorter than approximately four years.
However, the supplementary question is also of importance. The timing of a human mission to Mars is critical. Here the optimal time for a flight to leave Earth is when solar activity is at its peak (the ‘solar maximum’).
Solar maximum refers to the regular period of greatest Sun activity during the 11-year solar cycle. At this time, large numbers of sunspots appear, and the solar irradiance output grows substantially.
During the solar maximum it is possible to effectively shield a Mars-bound spacecraft from the bombarding energetic particles emanating from the Sun since during this astronomical period, the most dangerous and energetic particles are deflected by the enhanced solar activity.
The research predictions reveal that galactic cosmic ray activity is at its lowest within the six to 12 months after the peak of solar activity. With solar energetic particles, the intensity is greatest during solar maximum.
Given the average flight to Mars takes about nine months, the timing of launch and the technological process, means that it is quite probable that a human mission could reach the planet and return without causing undue risk to the astronauts aboard.
The study appears in the journal Space Weather, titled “Beating 1 Sievert: Optimal Radiation Shielding of Astronauts on a Mission to Mars.”
