| Title | Manned Mars Mission Radiation Danger Increasing | |
| Date | Friday October 24 2014, @08:43PM | |
| Author | Blackmoore | |
| Topic | ||
| from the in-space-noone-can-hear-you-cook dept. | ||
The Register reports
A drop in the solar wind of a kind not seen since 1715 has made travel beyond Earth orbit a lot more dangerous, according to Professor Nathan Schwadron, studying data from the Cosmic Ray Telescope for the Effects of Radiation – so much so that a manned Mission to Mars may not be feasible for many decades.
The Sun may be entering a so-called "Maunder Minimum", a lengthy spell of low activity. Such a minimum last occurred from 1645-1715. Solar Minimums are characterized by significant reduction in the solar wind.
The solar wind normally has the effect of reducing the amount of dangerous cosmic radiation that can reach the inner solar system. While particles and radiation from the Sun are dangerous to astronauts, cosmic rays are even worse, so the effect of a solar calm is to make space even more radioactive than it already is.For the sake of planning, a 3 per cent risk of an astronaut dying due to radiation exposure during a mission is seen as the acceptable limit: it's a dangerous job, after all (one should note that the death would probably be after the mission from cancer, perhaps many years later, rather than from severe radiation sickness while still in space). From Schwadron and his crew's analysis, if a lengthy solar quiet spell is indeed in the cards, the maximum time an astronaut can reasonably spend in space will be well under a year.
The time to 3 per cent Risk of Exposure Induced Death (REID) in interplanetary space was less than 400 days for a 30 year old male and less than 300 days for a 30 year old female in the last solar Maximum cycle.
The time to 3 per cent REID is estimated to be ~20 per cent lower in the coming solar Minimum cycle. If the heliospheric magnetic field continues to weaken over time, as is likely, then allowable mission duration will decrease correspondingly to about 320 days for men, 240 days for women.
Using our current technology, Space.com says the fasted time to Mars orbit is 168 days, making even a manned fly-by mission perilously close to the 300 day limit.
One way missions would still seem possible. But the Martian atmosphere provides precious little shielding and a solar minimum would double the amount of cosmic radiation on the surface.
Former NASA astronaut Dr Franklin Chang Díaz has suggested that nuclear plants of the type used in submarines could power plasma rockets to take a crewed ship to Mars in a month.
| Links |
printed from SoylentNews, Manned Mars Mission Radiation Danger Increasing on 2024-04-23 10:29:36