It’s not long before a conversation about space travel is likely to turn to the impact on the human body. Our bodies have evolved to exist on Earth with a constant force of 1G acting upon them but up in orbit, all of a sudden that force is apparently lacking. The impact of this is well known; muscle loss and reduction in bone density but there are effects of spaceflight. Cosmic radiation from the Galaxy has an impact on cognition too, an effect that has recently been studied in mice!
When an object like the space station is in orbit around the Earth it is in a state known as freefall. This means it is constantly falling to Earth but the curvature of the Earth is constantly falling away from it. In other words, it is constantly falling but never reaches the ground. This state means anyone or anything inside the space station would also fall at the same rate but this would be experienced as floating. Muscle loss and reduction in bone density are the well known impacts of such an environment but there are more that await a space traveller.
ESA astronaut Alexander Gerst spent six hours and 13 minutes outside the International Space Station with NASA astronaut Reid Wiseman on Tuesday, 7 October 2014. This was the first spacewalk for both astronauts but they performed well in the weightlessness of orbit. Credit: NASA/ESAGalactic cosmic radiation (GCR) is made up of energy originating from sources outside of our Solar System. These tend to be from supernova explosions and other energetic events in deep space. The particles from GCR are mostly protons and electrons along with some heavier nuclei. They can penetrate our atmosphere but the Earth’s magnetic field offers some protection to those on the surface. To those venturing out into space, things are a little less rosey for GCR can have quite an impact on astronauts.
Sources of Ionizing Radiation in Interplanetary Space. The Radiation Assessment Detector (RAD) on NASA’s Curiosity Mars rover monitors high-energy atomic and subatomic particles coming from the sun, distant supernovae and other sources. The two types of radiation are known as Galactic Cosmic Rays and Solar Energetic Particles. RAD measured the flux of this energetic-particle radiation while shielded inside the Mars Science Laboratory spacecraft on the flight delivering Curiosity from Earth to Mars, and continues to monitor the flux on the surface of Mars. Credit: NASA/JPL-Caltech/SwRIGCR is a real problem for longer duration space exploration like trips to Mars since currently, the radiation can penetrate spacecraft shielding and be a real threat to human health. Studies to date have shown that GCR can have an effect cognitive abilities on mice in the short term however a new study paints a rather more bleak picture. The paper published in the Journal of Neurochemistry reports that GCR exposure can have long lasting effects too.
Surprisingly, the team studied the impact on both male and female mice by subjecting them to a multi-particle spectrum GCR similar to the radiation that would be experienced on a deep space mission. The experiment was undertaken at Brookhaven National Laboratory where a 33-ion beam was used to simulate radiation from space. The team found that the radiation impaired numerous central nervous system functions from memory, pattern separation (when the brain minimises overlap between patterns of neuronal activity that represents similar experiences), anxiety, vigilance, social novelty (tendency to spend time with a previously unknown mouse rather than a familiar mouse!) and motor controls.
The discovery that the impact on females was more pronounced was unexpected but the team also established that mice which were fed an antioxidant and anti-inflammatory drugs known as CDDO-EA were less effected. The findings will be of immediate benefit to space exploration but will also help us to understand the long term impact on our cognition from radiation.
Source : Can cosmic radiation in outer space affect astronauts’ long-term cognition?
