The Milky Way is a wild west of highly energetic, subatomic particles blitzing across the galaxy at speeds approaching the speed of light. As these galactic cosmic rays careen around our corner of space, sometimes they. Largely thanks to the atmosphere (and Earth's magnetic fields) they don't pose a huge problem to human health on the ground. But in space it's a different story.
In space, exposure to GCRs, or space radiation, can damage DNA, play havoc with the brain and may affect the normal biological function of cells. However, the effects of cosmic rays on astronauts are still poorly understood. If we're ever going to travel further into the cosmos or spend months on the moon or Mars, we need to unravel how our bodies might be affected by the rays.
So, of course, NASA built a machine that fires beams of high-energy particles to begin testing exactly how space radiation might affect us. We're calling it now: This is a cosmic ray gun -- it's just not the kind of weapon that's going to do any immediate, obvious damage.
In a new study, published in the open-access journal PLoS Biology on Tuesday, scientists at the NASA Space Radiation Laboratory in Brookhaven, New York, detail the development and use of the first ground-based "galactic cosmic ray simulator" which is able to recreate more accurately the actual radiation environment found in space.
Cosmic rays are made up of a mixture of energetic particles such as protons, helium ions and heavier ions like carbon and iron. In the past, scientists have had the ability to fire beams of energetic particles at one another, but only one at a time. However, because the mixture of particles in GCRs interact with spacecraft and the human body in different ways, scientists are interested in exploring how they all work together.
In reality, the simulator is less "gun" and more "particle accelerator." The simulator uses Brookhaven's Booster synchotron, which is able to shoot and accelerate particles to extremely high energies which the laboratory can use. Then the lab can control how the GCR beams are delivered to a target area.
"Using well established environmental models of the space environment, radiation physics, and human body geometry, we have
estimated the number of particles and their energies that will reach critical body organs -- like the brain, lungs, and liver," says Lisa Simonsen, space radiation researcher at NSRL and first author on the study.
New technology, like beam switching, allows the simulator to shift between different beam combinations rapidly, mimicking the space environment more closely. The beams, which can measure 60x60 centimeters square, are able to be focused on a target area to deliver a dose of space radiation as researchers see fit.
"Rapid switching technology allows all of the relevant particle types and energies to be covered in a single experiment," says Simonsen.
The first experiments performed by NASA scientists began in 2018 and are evaluating acute and chronic doses of radiation in mice. The animals can be placed inside their cages and receive a dosage of space radiation right here on Earth. The results of these early experiments are yet to be published, but the authors suggest the first run of the cosmic ray simulator will allow them to plan for future operations. And it's not just for biological studies, either. The GCR simulator could be focused on different materials to understand how they might fare in spacecraft shielding.
"We are very excited to see our first published results coming out sometime this coming year to understand mixed ion effects, dose rate effects, and countermeasure efficacy in a simulated space environment," says Simonsen.
We already have an inkling about how the human body changes when it leaves the Earth. Before we can travel deeper among the stars, we need to learn the potential nasty effects we might experience on long-distance journeys. The GCR simulator is a massive technological leap forward that will help us put our feet on more distant worlds.