Interview with Alexa Halford: space physics
Alexa Halford uses HABs to study space weather. In particular, she is interested in what happens when high energy particles emitted from the sun come into contact with earth’s magnetosphere, or the region of space dominated by earth’s magnetic field. Sometimes, these powerful particles lead to electronic anomalies or hardware damage, causing problems for satellites, radio communications, and devices on earth’s surface. Storms can even be unsafe for astronauts. The effects of a solar storm could have devastating results, yet the ability to accurately predict the magnitude of the storm is still a major challenge.
One extreme event in 1859 caused telegraph systems all over the world to fail. A similar event today would cause major power blackouts, communication losses, and be very expensive. It has been estimated that a similar storm would cost over a trillion dollars in losses!
Sometimes we worry too much; satellites and spacecraft are unnecessarily shut down to protect them from damage. With a better understanding of the space environment which will lead to more accurate modeling and predictions, scientists could give more accurate forecasts. Scientists are also currently working to understand the daily, less catastrophic effects of space weather on our technology. Even small perturbations of our magnetosphere end up affecting power grids. Understanding this will allow us to potentially take advantage of these blips in the power grid.
The storms don’t just affect earth. For example, Mars has a weak magnetic field, and just like how a thin comb-over blows away in the wind, it appears much of Mar’s atmosphere got blown away earlier in the history of our solar system. It is thought that without a strong magnetic field to help hold it in place, the Martian atmosphere was blown away by solar winds. Without the atmosphere to hold in heat, the water that may have made life possible on Mars long ago froze. Liquid water is thought to be essential for life, and we all should take a moment to thank our magnetic field for protecting us. Check out the video below from Science@NASA for more about these particles and our magnetic field.
Ok, so what can balloons tell us about the state of our magnetosphere? Alexa explains that X-rays are created when electrons in earth’s magnetic field are pushed into uncharged particles in the atmosphere. Instruments aboard her group’s balloons measure X-rays, and they can thus infer when electrons are lost from the magnetosphere. They compare what they see from their balloons with other ground based sensors to get an idea of not only what is happening to electrons during storms, but also protons. To get these measurements, the BARREL team, which stands for the Balloon Array for Radiation-belt Relativistic Electron Losses, has traveled to some pretty cool places like Antarctica and Sweden. It is led by Robyn Millan at Dartmouth College, where Alexa is currently a joint post-doc with NASA Goddard.
Alexa tells us the balloons in Antarctica got some great data, but there were not as many ground sensors as there are in Sweden. The combination of balloons and other ground based measurements in Sweden allows them to look at lower energy precipitation as well as allow for more direct comparisons to learn about lost protons. Importantly, the balloons allow for better time and location resolution than ground sensors alone. Together, this will help inform us about the dynamics of the magnetosphere due to a geomagnetic storm.
In addition to ground sensors, some satellites have specific high-resolution equipment to study similar conditions from space, and their data can also be combined with those from the balloons. The BARREL team initially got funding to work with some of these satellites, the Van Allan probes, and they are now also working with CubeSats in low earth orbit.
How could the amateur HAB community get involved? Wouldn’t it be cool to have a space weather station in your backyard?! Alexa told us that X-ray scintillation kits, or a miniaturization of their group’s payload, costs ~$5,000 USD, which leaves many clubs and high schools out of this type of research. However, the cost is reasonable for many universities. We discussed with Alexa possible avenues for funding such as the National Science Foundation’s EPSCoRE program or a National Geographic grant. For now, adding an extra X-ray sensor to your balloon is probably not a practical choice, but following the cutting edge research in this area can be rewarding.
One area of promising research is atmospheric chemistry. Ultimately, these raining particles affect the sky’s chemistry, and may lead to the formation of compounds such as nitric oxide. These reactions have in the past been a bit of a black box to the atmospheric community. Quantifying how much energy is precipitating and what storm components contribute to atmospheric chemistry (high versus low energy particles or electron versus proton precipitation) should continue to be a hot area of research in the future.
You can read about Alexa’s story in her own words here:
Both HAB amateurs and professionals can avoid interference of their radio communication systems by following the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center.