Photo of a coronal mass ejection, together with a part of a solar filament, triggered by the sun on Feb. 24, 2015. If the sun is active, the magnetic field gains strength and extends further out in space, to help deflect the energy of cosmic rays from the vicinity of the inner solar system.
(Solar Dynamics Observatory of NASA)
Space radiation, is a bigger worry for voyaging astronauts than scientists thought, at least in the near future, a new study suggests.
“The radiation dose rates from measurements obtained over the last four years exceeded the trends from the previous solar cycles by at least 30 percent, showing that the radiation is getting much more intense,” study lead author Nathan Schwadron, a professor of physics at the University of New Hampshire’s Space Science Center, said in a statement.
“These particles radiation conditions are important environmental factors for space travel and space weather, and should be carefully studied and incorporated in the planning and design of future missions to the moon, Mars, asteroids and beyond,” Schwadron added. [How Radiation in Space Poses a Threat to Human Exploration (Infographic)]
Schwadron and his colleagues studied the observations of NASA’s Lunar Reconnaissance Orbiter (LRO), one that has been circling the moon since 2009. Specifically, they looked at dose rates of galactic cosmic rays measured over the past four years by LRO’s Cosmic Ray Telescope for the Effects of Radiation (CRATER).
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Lunar Reconnaissance Orbiter
Galactic cosmic rays (GCRs) are super-energetic particles — mostly protons and atomic nuclei that are accelerated to enormous speeds by far, and dramatic events such as supernova explosions. GCRs may cause damage to spacecraft electronics and, in large enough doses can cause radiation sickness in astronauts, and in the longer-term problems, such as cancer.
“We now know that the radiation of deep space, that we could send the human crew up to this point is very different compared with those of previous manned missions to the moon,” Schwadron said, referring to NASA’s Apollo missions, which landed six crews on the lunar surface between July 1969 and December 1972.
The increase of the GCR levels is associated with a prolonged stretch of low solar activity, which changes on an 11-year cycle. During the active phases, the sun’s magnetic field spreads throughout the solar system more extensively (by the flow of charged particles known as the solar wind), and it allows more incoming GCRs.
But an active sun poses its own problems. Solar flares and coronal mass ejections — powerful blast that huge clouds of hot plasma ejected into space at millions of miles per hour, and can also result in an increase of the radiation significantly.
And large solar eruptions are not limited to the active periods of the solar cycle. Indeed, a series of solar eruptions in September 2017, increased deep-space radiation significantly, the researchers said.
The new study has been accepted for publication in the journal Space Weather.
Originally published on Space.com.