by NASA has set its sights on the Moon, aiming to return astronauts to the lunar surface by 2026 and establish a long-term presence there by the 2030s. But the Moon is not exactly a habitable place for humans.
cosmic rays from distant stars and galaxies and energetic solar particles from the Sun bombard the surface, and exposure to these particles can pose a risk to human health.
Galactic cosmic rays and energetic solar particles are high-energy particles that travel close to the speed of light.
While galactic cosmic radiation travels toward the Moon in a fairly steady stream, energetic particles can come from the Sun in large bursts. These particles can affect human flesh and increase the risk of cancer.
The Earth has a magnetic field that provides a shield against high-energy particles from space. But the Moon has no magnetic field, making its surface vulnerable to these particles.
During a large energetic solar particle event, the radiation dose received by an astronaut inside a space suit could exceed 1,000 times the dose received by a person on Earth. That would exceed the recommended astronaut life limit by 10 times.
NASA’s Artemis program, which 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’s CLEAR center, the Center for All-Clear SEP Forecasting, work on predictions. these particle emissions from the Sun. Forecasting these events may help protect future Artemis crew members.
11 year solar cycle
The Moon is facing dangerous levels of radiation in 2024, as the Sun approaches the maximum point in its 11-year solar cycle. This cycle is driven by the Sun’s magnetic field, which changes its overall strength significantly every 11 years. When the Sun is approaching its maximum activity, up to 20 large energetic solar particle events can occur each year.
Both solar flares, which are sudden bursts of electromagnetic radiation from the Sun, and coronal mass ejections, which are the expulsion of large amounts of material and magnetic fields from the Sun, can produce energetic particles.
The Sun is expected to reach its solar maximum in 2026, the target launch time for the Artemis III mission, which will land an astronaut crew on the surface of the Moon.
Although researchers can follow the Sun’s cycle and predict trends, it is difficult to measure exactly when each energetic solar event of particles 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
In 2023, NASA funded a five-year space weather center of excellence called CLEAR, which aims to predict the probability and intensity of energetic solar particle events.
Currently, forecasters at the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center, the center that tracks solar events, cannot issue a warning of an incoming energetic solar particle event until it detects They solar flare or coronal mass eruption. They find these by looking at the Sun’s atmosphere and by measuring X-rays that flow from the Sun.
Once a solar flare or coronal mass ejection is detected by a forecaster, the high-energy particles usually reach Earth within less than an hour. But astronauts on the surface of the Moon would need more time to seek shelter. My team at CLEAR is trying to predict solar flares and coronal mass eruptions before they happen.
Although scientists do not fully understand what causes these solar events, they do know that the Sun’s magnetic field is one of the main drivers. Specifically, they are studying the strength and complexity of the magnetic field in certain regions of the Sun’s surface.
At the CLEAR center, we will monitor the Sun’s magnetic field using measurements from ground-based and space-based telescopes and build machine learning models that predict solar events—hopefully more than 24 hours before they occur.
With the forecasting framework developed at CLEAR, we also hope to predict when the particle flux will fall back to a safe level. That way, we will be able to tell the astronauts when it is safe to leave their shelter and continue their work on the surface of the moon.
This article is republished from The Conversation, a non-profit, independent news organization that brings you reliable facts and analysis to help you make sense of our complex world. It was written by: Lulu Zhao, University of Michigan
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Lulu Zhao serves as principal investigator of CLEAR at the University of Michigan, which receives funding from NASA.
