It may sound like science fiction, but astronauts traveling into deep space are bombarded by cosmic rays. Radiation exposure is a scientific fact. Ahead of future missions to the Moon and Mars, scientists at the University of New Hampshire Space Research Center warn that radiation levels are much higher than previously thought, and this could have serious implications for both astronauts and satellite technology.
“The radiation doses measured over the past four years have exceeded the values of previous solar cycles by at least 30%, indicating that the radiation situation is becoming much more intense. These conditions are essential for space travel and space weather, and must be carefully studied and considered when planning and designing future missions to the Moon, Mars, asteroids and beyond,”said Nathan Shwadron, professor of physics and lead author of the study.
In a new study, scientists have found that particle fluxes in Galactic Cosmic Rays (GCRs) are growing faster and are on track to surpass record levels in the entire space era. It is also noted that in September 2017, one of the most significant events of Solar Energy Particles (SES) occurred, releasing large doses of radiation that can pose a serious threat to both people and satellites. Unprotected astronauts from radiation can develop radiation sickness or long-term health problems such as cancer and damage to organs including the heart, brain, and central nervous system.
In 2014, Schwadron and his team predicted a 20 percent increase in the dose rate from one solar minimum to the next. Four years later, their latest research shows that current conditions exceed their forecasts by about 10%, showing that the radiation situation is even worse than expected.
“We now know that the conditions in deep space are completely different from those of previous crewed missions to the moon,” says Shvadron.
The authors used data from the CRaTER instrument on the NASA LRO lunar orbiter. These and other space observations show that GCR radiation doses are growing faster than previously thought. Researchers point to an abnormally long period of recent declines in solar activity. When the sun is active, frequent spots appear on it, which can increase the magnetic field. This magnetic field is then spread by the solar wind through the solar system and deflects galactic cosmic rays from it and from astronauts.
During most of the space era, the activity of the Sun decreased and proceeded in 11-year cycles, in which a lull, called the solar minimum, is observed for 6-8 months, followed by 2-3 years of activity. But since 2006, scientists have observed the longest solar minimum and the weakest solar activity in the entire space era.
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Despite this general decline, solar eruptions in September 2017 triggered episodes of significant SES events and associated radiation caused by particle acceleration by successive magnetically coupled coronal mass ejections.
According to the scientists' conclusions, the radiation environment continues to pose significant dangers associated with both historically large streams of galactic cosmic rays and large, but isolated SES events that impede the ability to predict space weather.
The research is published in the journal Space Weather.
