NASA has its sights set on the moon, with the goal of sending astronauts back to the lunar surface by 2026 and establishing a long-term presence there by 2030. But the moon isn’t exactly a habitable place for humans.
Cosmic rays from distant stars and galaxies and solar energetic particles from the Sun bombard the surface, and exposure to these particles can pose a risk to human health.
Both galactic cosmic rays and solar energetic particles are high-energy particles that travel close to the speed of light.
As galactic cosmic rays trickle toward the moon in a relatively steady stream, energetic particles can come in large bursts from the sun. These particles can penetrate human flesh and increase the risk of cancer.
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The Earth has a magnetic field that forms a shield against high-energy particles from space. But the moon has no magnetic field, making its surface vulnerable to bombardment by these particles.
During a large solar energetic particle event, the radiation dose received by an astronaut in a space suit may be exceeded 1000 times the dosage someone uses Soil receives. That would exceed the recommended amount for an astronaut lifetime limit by 10 times.
NASAs Artemis programwhich began in 2017, plans to restore a human presence on the moon for the first time since 1972. My colleagues and I at the University of Michigan CLEAR Center, the Center for All-Clear SEP Forecast is working to predict these particle emissions from the sun. Predicting these events can help protect future Artemis crew members.
A solar cycle of 11 years
The moon will face dangerous radiation levels in 2024 as the sun approaches the maximum point in its eleven-year existence. solar cycle. This cycle is driven by the sun’s magnetic field, the total strength of which changes dramatically every eleven years. As the sun approaches maximum activity, as many as 20 large solar energetic particle events can occur each year.
Both solar flaresthese are sudden bursts of electromagnetic radiation from the sun, and coronal mass ejectionsthat expel a large amount of matter and magnetic fields from the Sun can produce energetic particles.
The sun is expected to come out its solar maximum in 2026, the target launch time for the Artemis 3 mission, which will land an astronaut crew on the moon’s surface.
Although researchers can track the sun’s cycle and predict trends, it is difficult to guess when exactly each solar energetic particle event will occur and how intense each event will be. Future astronauts on the moon will need a warning system that more accurately predicts these events before they happen.
Predicting solar events
By 2023, NASA financed for five years space again center of excellence called CLEARwhich aims to predict the probability and intensity of solar energetic particle events.
Currently forecasters from the National Oceanic and Atmospheric Administration Center for Space Weather Forecastingthe center that monitors solar events cannot issue a warning of an incoming solar energetic particle event until they actually detect a solar flare or flare. coronal mass ejection. They detect these by looking at the sun’s atmosphere and measuring the X-rays coming from the sun.
Once a forecaster detects a solar flare or coronal mass ejection, the high-energy particles typically arrive at Earth within an hour. But astronauts on the moon’s surface would need more time to find shelter. My team at CLEAR wants to predict solar flares and coronal mass ejections before they happen.
Although scientists don’t fully understand what causes these solar events, they do know that the sun’s magnetic field is one of the most important factors. Specifically, they study the strength and complexity of the magnetic field certain regions on the surface of the sun.
At the CLEAR center we will monitor the Sun’s magnetic field using measurements from ground-based and space-based telescopes. machine learning models that predict solar events – hopefully more than 24 hours before they happen.
With the prediction framework developed at CLEAR, we also hope to be able to predict when the particle flux will fall back to a safe level. This way we can tell the astronauts when it is safe to leave their shelter and continue their work on the moon’s surface.