Mars missions at risk: Could toxic dust threaten astronauts’ health and safety?

Mars has long been considered a prime candidate for human exploration, with both Nasa and the Chinese Manned Space Agency (CMS) planning crewed missions to the Red Planet in the coming decades.

However, new research suggests that toxic dust storms on Mars pose a significant risk to astronaut health and mission success.

A recent study published in the journal GeoHealth highlights how the fine, electrostatically charged dust covering the Martian surface contains hazardous compounds such as silica, perchlorates, gypsum and nanophase iron oxides.

These substances, when inhaled, could lead to severe respiratory conditions, thyroid dysfunction, and other life-threatening ailments.

Scientists from the Keck School of Medicine at the University of Southern California (USC), UCLA Space Medicine Center, and Nasa’s Johnson Space Center collaborated on this research, stating the need for robust mitigation strategies to protect future astronauts from these hazards.

What is the threat posed by Martian dust storms?

Every Martian year (lasting about 687 Earth days), regional dust storms coincide with the planet’s southern hemisphere summer. Every three Martian years (roughly five and a half Earth years), these storms expand into global dust storms that envelop the entire planet and can be observed from Earth.

These storms are already known to be a serious hazard for robotic missions. In 2018, Nasa’s Opportunity Rover was lost after a massive dust storm coated its solar panels, rendering it unable to generate power.

Similarly, the InSight Lander succumbed to dust accumulation in 2022, losing the ability to operate its scientific instruments.

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For crewed missions, the implications are even more concerning. Prolonged exposure to Martian dust could have dire health consequences, given its unique composition and physical properties.

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Unlike dust on Earth, which becomes rounded due to weathering, Martian dust particles are jagged and abrasive, making them more likely to damage lung tissue and other sensitive biological membranes.

How can Martian dust affect astronaut health?

One of the primary concerns is the ability of Martian dust to penetrate deep into the respiratory system. “There are many potential toxic elements that astronauts could be exposed to on Mars,” explained Dr. Justin Wang, a medical researcher at USC.

“Most critically, there is an abundance of silica dust in addition to iron dust from basalt and nanophase iron, both of which are reactive to the lungs and can cause respiratory diseases.”

Silica exposure is particularly dangerous because it can lead to silicosis, a lung disease commonly found among miners and construction workers on Earth.

“Silicosis and exposure to toxic iron dust resemble coal worker’s pneumoconiosis, which is common in coal miners and is colloquially known as black lung disease,” Wang added.

Perchlorates, another toxic component of Martian dust, could disrupt thyroid function and lead to serious blood disorders such as aplastic anemia, a condition where the body stops producing enough blood cells.

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“Astronauts are already at risk for pulmonary fibrosis due to the radiation exposure in spaceflight, and many of the hazards including silica and iron oxides can cause pulmonary disease that could be superimposed,” Wang noted.

During the Apollo missions, astronauts who came into contact with lunar regolith experienced symptoms such as coughing, throat irritation, and watery eyes due to the fine, clingy nature of moon dust.

Martian dust is expected to behave similarly but with even greater toxicity due to the presence of heavy metals like chromium, beryllium, arsenic, and cadmium, which have been linked to serious health conditions on Earth.

What engineering challenges does Martian dust pose?

In addition to health risks, Martian dust could pose significant technical challenges for spacecraft, habitats, and scientific equipment. “It’s constantly falling from the sky and covering everything,” said Professor Brian Hynek from the University of Boulder.

“Every few years there are globe-encompassing storms that lay down a thick coat.” Dust accumulation on solar panels, landers and spacesuits could lead to mission failures if proper cleaning and maintenance strategies are not implemented.

“Our rovers have already experienced this with loss of scientific instruments or the entire mission due to solar panels rendered too dusty to charge the batteries,” Hynek told CNN.

Dust infiltration into habitats could also create long-term exposure risks for astronauts, necessitating advanced air filtration systems.

Julia Cartwright, an independent research fellow at the University of Leicester, pointed out that dust mitigation is a major issue for space exploration. “On the Moon and Mars, you’re dealing with very sharp, pointy particles that haven’t been worn down over time,” she told CNN. “This is a problem if they are in the air that you are breathing – sharp particles are more likely to cause irritation to soft membranes, which is where you can run into issues with your lungs.”

The challenges extend to air purification as well. “Assuming that you are able to filter these out, you would still need to have a strategy for changing out all of the filters that you would have to breathe through and you would need to have a load of those filters on board the spacecraft,” Cartwright explained.

What can be done to avoid this?

Given that a round-trip Mars mission could last three years, with astronauts spending at least a year on the planet’s surface, medical intervention will be significantly more complex than for missions to the International Space Station (ISS) or the Moon.

“The distance from Earth to Mars means that rapid evacuation back to Earth is ruled out, and so it’s necessary to have a complete medical capability locally on the surface,” Professor Jonathan Eastwood of Imperial College London told CNN.

Preventing dust exposure will be key to ensuring astronaut safety. Strategies under development include air filtration systems, cabin cleaning techniques and electrostatic repulsion devices to keep dust from adhering to spacesuits and habitat interiors.

Wang and his colleagues also highlighted dietary interventions, such as vitamin C supplementation to mitigate chromium exposure and iodine to counteract thyroid damage from perchlorates.

However, they cautioned that excessive supplementation carries risks. “Taking too much vitamin C can increase the risk of kidney stones, which astronauts are already at risk for after spending extended periods in microgravity,” Wang noted.

Nasa and other space agencies are actively researching technologies to counteract the dangers of regolith. Protective coatings, specialised sprays, and electron beams are among the solutions being tested to reduce dust adhesion.

Additionally, ongoing studies are examining how Martian dust behaves in different environments, helping scientists design better countermeasures.

Natalya Zavina-James, senior exploration research manager at the UK Space Agency, conveyed the broader implications of these findings.

“The study illustrates the breadth of considerations needed to protect astronauts’ health,” she told CNN. “It’s great to begin to see studies, like this one, addressing the human health aspect of Mars exploration. This is a critical aspect of the horizon goal, with huge ethical implications that must be considered in depth before crewed missions take off.”

Despite its dangers, Martian dust is not an insurmountable obstacle. “While the dust on Mars isn’t going to be the most dangerous part of a mission to the Red Planet, it’s definitely a hazard that can be harmful to astronauts, yet easily avoidable given we’re properly prepared for it,” Wang said.

As the Artemis programme progresses and plans for human exploration of Mars take shape, developing comprehensive medical, engineering and operational strategies will be essential.

With inputs from agencies