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Space radiation is increasing. That might put a stop to human visitors to Mars

Mars mission: how increasing levels of space radiation may halt human visitors, The Conversation, Gareth Dorrian, Post Doctoral Research Associate in Space Science, Nottingham Trent University, Ian Whittaker, Lecturer, Nottingham Trent University, 

From surviving take off to having to rely on oxygen tanks to breathe in orbit, space travel is incredibly risky. But a huge hazard that we sometimes overlook is high energy radiation from sources both inside and outside the solar system.

A new study, published in the journal Space Weather, has shown that radiation received from outside our solar system has been increasing steadily for the last few years, returning to levels not seen since the first half of the 20th century – making space travel more dangerous today than it was during the Apollo era.

This type of radiation, known as “galactic cosmic rays”, consists of the nucleus of an atom travelling very close to the speed of light. These rays, many of which come from our own Milky Way galaxy, are some of the most energetic particles in the known universe and are found throughout the solar system.

Humans have a limited tolerance to radiation of all kinds. Particle radiation can damage DNA in human cells, cause mutations and stimulate cancer. In extreme circumstances, an acute dose of radiation can cause sickness, burns and organ failure. Anyone who works near sources of radiation has a maximum annual limit on the dose they can safely receive.

Solar cycle

In space, astronauts are partially shielded from galactic cosmic rays by the magnetic field of the sun, which deflects some of these incoming charged particles. However, the sun’s magnetic field varies in strength over time, with the 11-year solar activity cycle. At solar minimum (when the sun is least active), the solar magnetic field is weaker, allowing more galactic cosmic rays into the solar system – posing a greater radiation hazard to astronauts.  At solar maximum, the opposite is true………..

New data

Since the last solar minimum in 2009, however, the sun appears to have returned to a quieter state once again. In fact, it has not been this quiet since the end of the 19th century. This change appears to be having a strong influence on the level of incoming galactic cosmic rays once again. Since the most recent solar minimum, the new study shows this specific radiation level is on the rise once more – it is currently some 30% higher than it was on average during the latter, quieter, part of the 20th century.

Scientists are currently debating whether these radiation levels will continue to rise. Our lack of knowledge about the underlying science of long-term variation in solar cycles is making it difficult to know for sure. Several studies predict that we are entering a new period of extended solar minimum conditions. But others suggest that current conditions are just part of the normal, long-term variation in solar cycles, and nothing out of the ordinary.

Either way, this evidently has major implications for future manned space missions. Although it is not the only factor to take into account. As well as charged particle radiation from the galaxy, the sun also produces this type of radiation in the form of solar energetic particles, which are produced more often, though not exclusively, at solar maximum………. https://theconversation.com/mars-mission-how-increasing-levels-of-space-radiation-may-halt-human-visitors-94052

 

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March 28, 2018 - Posted by | 2 WORLD, technology

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