NASA has set its sights on the moon with the goal of sending astronauts back to the lunar surface by 2026 and ensuring a long-term presence there until the 2030s. But the moon is not 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.
While galactic cosmic rays flow toward the Moon in a relatively steady stream, energetic particles can they come from the sun in large doses. These particles can penetrate human flesh and increase the risk of cancer.
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Earth has a magnetic field that provides a shield against high-energy particles from space. But the Moon has no magnetic field, so its surface is susceptible to bombardment by these particles.
During a large solar energy particle, the dose of radiation received by an astronaut in a space suit could exceed 1000 times dosage someone on Earth accepts. This would exceed the astronaut’s recommendation lifetime limit 10 times.
NASA Artemis programwhich began in 2017, intends to restore a human presence on the moon for the first time since 1972. Me and my colleagues at the CLEAR Center at the University of Michigan, The Center for All-Clear SEP Forecast, works to predict these particle ejections from the Sun. Anticipating these events can help protect future Artemis crew members.
11 year solar cycle
The Moon faces dangerous levels of radiation in 2024 as the Sun approaches its 11-year maximum. solar cycle. This cycle is controlled by the Sun’s magnetic field, whose overall strength changes dramatically every 11 years. As the Sun approaches its maximum activity, up to 20 large solar energetic particles can occur each year.
Both solar flarewhich are sudden eruptions of electromagnetic radiation from the sun, and coronal mass ejectionswhich are ejections of large amounts of matter 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 3 mission to land an astronaut crew on the lunar surface.
While researchers can track the solar cycle and predict trends, it is difficult to predict exactly when each solar energy 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
in 2023 NASA financed for five years space weather center of excellence named CLEARwhich aims to predict the probability and intensity of solar energy particle events.
Right now, forecasters at the National Oceanic and Atmospheric Administration Space Weather Prediction Centera center that monitors solar events cannot issue a warning for an incoming solar energetic particle event until it actually sees a solar flare or coronal mass ejection. They detect them by looking at the solar atmosphere and measuring the X-rays that flow from the Sun.
Once a forecaster detects a solar flare or coronal mass ejection, the high-energy particles typically reach Earth in less than an hour. But astronauts on the surface of the moon would need more time to find shelter. My team at CLEAR wants to make predictions solar flare and coronal mass ejections before they occur.
While scientists don’t fully understand what causes these solar events, they do know that the Sun’s magnetic field is one of the key driving forces. Specifically, they study the strength and complexity of the magnetic field in 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 and build machine learning models that predict solar events – hopefully more than 24 hours before they happen.
With the forecasting framework developed at CLEAR, we also hope to predict when the particle flux will drop back to safe levels. This way we will be able to tell the astronauts when it is safe to leave their shelter and continue working on the lunar surface.