This past weekend, Mars swung closer to Earth than it will for the next decade, and coincidentally a dust storm kicked up and gave skywatchers something special to view.
While the red planet looks close enough to grab through a telescope, NASA doesn’t plan to send people there until after 2020, and even that far-off date could be pushed back by something as seemingly insignificant as dust.
According to a NASA report that evaluates the risks of sending a manned mission to Mars, Martian dust poses as one of the biggest potential problems.
Compared to here, dust on Mars is thought to be larger and rougher, like the dust that covers the Moon. When Apollo astronauts landed there, they were covered in just a few minutes. Within hours, rough lunar dust had scratched up lenses and degraded seals.
While the lunar stays were short, if astronauts make the six-month journey to Mars, they’ll likely be expected to stay a while. That would give potentially hazardous dust plenty of time to accumulate in equipment, cause airlock malfunctions, or even infiltrate astronauts’ lungs.
“Martian dust is a number one risk,” says Jim Garvin, NASA chief scientist at the Goddard Space Flight Center. “We need to understand the dust in designing power systems, space suits and filtration systems. We need to mitigate it, keep it out, figure out how to live with it.”
Perfect dust storm
Dust on Mars doesn’t just sit on the ground – it gets furiously swept about in dust devils and massive dust storms. This past weekend skywatchers could easily spot an 800-mile-wide dust storm as it spun across Mars at 35 mph.
Every once and a while, Mars experiences the “perfect dust storm,” where powerful winds kick dust up into the atmosphere where it is spread around until it eventually clouds the entire planet.
One of these rare storms would obviously make it difficult for a spacecraft to land or take off from the planet’s surface, but even smaller storms like the one this past weekend are a substantial mission risk, making atmospheric wind forces the number two mission risk, according to the report.
While dust and wind are two major mission risks, the team of scientists that contributed to NASA’s Mars Exploration Program Analysis Group report believe that future orbiters and robotic missions could help us better understand the planet and reduce these risks.
“We could observe Martian wind speeds at different altitudes, which is vital both for targeting accuracy when a mission lands, and for reaching the right orbit when the mission departs,” said David Beaty, Mars Program Science Manager and the report’s lead author.
Although signs of life haven’t been discovered on Mars, that might be a different story in 25 years. The possibility that microbial organisms, or their remains, could exist in Martian soil is ranked as the number three mission risk.
Having never been exposed to these forms of alien life, they could stand as a substantial health risk to astronauts. The biggest concern to scientists, though, is that these life forms might hitch a ride back to Earth, where they could replicate, prosper, and do unknown damage.
Scientists say they need more robotic missions and soil sample return to truly evaluate this risk. Even a couple pounds of Martian dirt would be of tremendous value, Beaty said.
Once on Mars, exposure to radiation is a relatively low risk, even for a long mission, according to the report. This evaluation is supported by data from the Mars Odyssey spacecraft.
However, during the year spent traveling between planets, astronauts will not be protected by a planet’s atmosphere and will be exposed to a greater dose of radiation. NASA says this amount falls within the lifetime safety limits, and protective spacesuits and ships are in the works.
Not mentioned in the report, however, are the physiological effects to bone and muscle from time spent in reduced gravity environments. Astronauts returning from long missions on the International Space Station have suffered massive muscle and bone loss. These losses would be slowed by Mars’s gravity, which is 3/8 of Earth’s, but it could be disastrous if a crewmember broke their leg during the mission.
Scientists are currently exploring methods of slowing muscle and bone deterioration, including an exercise device that creates its own gravity.
The roundtrip journey to the red planet and back will take about a year. The mission spacecraft can carry only so much water. Every gallon takes up space that could be used for other supplies or equipment and raises the total mission cost.
However, reducing the water load on the spacecraft could force the astronauts into a situation where they would run out of water before they returned to Earth, especially if their stay on Mars is longer than anticipated.
For a long mission, potable water in some form that’s accessible near the landing site could address this risk, scientists write in the report. Future orbiter and robotic missions could help identify a region on Mars where water might be available to astronauts, which could reduce the risk of astronauts running out of water.
Water is also a source of breathable oxygen, which, for a yearlong stay on the planet, would be expensive to transport.
- Surviving Space: Risks to Humans on the Moon and Mars
- Mars Odyssey Shows Intense, But Managable Radiation Risk for Astronauts
- Delving into Dust Devils