Mars May Kill Astronauts — And It’s Not How You Think

March 30, 2025 by Melissa Ait Lounis

NASA’s biggest challenge on Mars might not be radiation or distance — but something far more insidious underfoot. New research uncovers a silent threat that could jeopardize astronaut survival long before the return trip.

As the race to send humans to Mars intensifies, scientists are sounding the alarm about a silent threat that could undermine every mission plan: toxic Martian dust.

A new study from the Keck School of Medicine at the University of Southern California (USC) reveals that the very soil of the Red Planet could cripple astronaut health, causing severe and possibly irreversible respiratory damage.

A Deadly Cocktail Underfoot

Beneath the surface-level calm of Mars lies an invisible danger. Its soil is filled with ultra-fine dust particles that scientists warn are both chemically aggressive and biologically invasive. “There are many potential toxic elements that astronauts could be exposed to on Mars. ” said Dr. Justin L. Wang, lead author of the study.

“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.“

The threat is worsened by the size of the particles. Martian dust is smaller than the minimum size that the mucus in our lungs is able to expel, allowing it to travel deeper into the lungs and remain lodged in tissue.

Storms That Spread Poison

Beyond its chemical makeup, Mars poses a second threat: its fierce climate. Every Martian year, the planet is battered by regional dust storms. And every few years, those storms expand into global events, filling the atmosphere with airborne grit.

In 2018, one such storm disabled NASA’s Opportunity rover by coating its solar panels and blocking sunlight. For astronauts, the implications go beyond power loss. These storms act as massive delivery systems for toxic particles.”Silicosis and exposure to toxic iron dust resemble coal worker’s pneumoconiosis,” Wang explained.

Warnings From The Moon

The risks of planetary dust are not hypothetical. Apollo astronauts encountered similar hazards on the Moon. Upon returning to their landers, many described persistent coughing, eye irritation, and even blurred vision after exposure to lunar dust. NASA later confirmed the most dangerous risks were tied to inhalation and vision interference.

Martian dust, however, adds another level of toxicity. Along with silica and iron, the regolith contains perchlorates, gypsum, and trace metals like arsenic, cadmium, and chromium. Some of these substances are known to be carcinogenic or highly toxic — but their combined effects in Martian conditions are still poorly understood.

Health Care, Millions Of Kilometers Away

When astronauts get sick on Earth, help is minutes away. On Mars, it’s a very different story. “It’s significantly more difficult to treat astronauts on Mars for diseases because the transit time is significantly longer than other previous missions to the ISS and the Moon.” the researchers noted.

A full mission could take three years, with crew spending a year or more in low gravity, high radiation, and constant exposure to toxic particles.

Treatments also come with trade-offs. Research suggests that“ vitamin C can help prevent diseases from chromium exposure and iodine”, meanwhile, may actually cause the thyroid diseases it’s meant to prevent.