Jumpstarting Mars’ Magnetic Field to Make It Habitable
by Abby Lee Hood  /  Nov 21, 2021

“Any long term human presence on Mars — colonization, research, visit and travel — that didn’t confine settlers to airtight compounds would rely on a stable atmosphere that doesn’t lose too many particles or fry human bodies with too much radiation. Now, scientists from a star-studded list of universities and organizations, including NASA’s own chief scientist James Lauer Green, are suggesting that we protect humans on Mars from deadly atmospheric conditions by jumpstarting the planet’s magnetic field. “For a long-term human presence on Mars to be established, serious thought would need to be given to terraforming the planet,” the team wrote in a new paper that will print in the journal Acta Astronautica in January 2022, first spotted by Universe Today. “One major requirement for such terraforming is having the protection of a planetary magnetic field which Mars currently does not have.” Earth has a strong magnetic field, but Mars’ is weak and fragmented.

One of the first goals of terraforming, according to the paper, would be increasing the atmospheric pressure above the Armstrong Limit, the threshold that allows humans to survive without a full-body pressure suit. Below that pressure limit, water in the lungs, eyes and saliva spontaneously boils, the team writes in their paper — and it’s hard to imagine we’ll be getting much done on any planet where humans turn into flesh soup. So just how much of a magnetic field would be needed to protect Mars and the humans that might someday live on it? Surprisingly, the team writes that the force needed to deflect say, solar wind, is about the same as a regular fridge magnet. But they’d need to generate it over the entire planet, a substantial challenge.

The scientists suggested a few ways to pull it off. These include restarting and circulating Mars’ iron core, creating a continuous solid loop or loop of solid-state magnets, or using a chain of coupled sources with a controlled beam or a plasma torus — a big ring, basically — of charged particles with an artificial current. This means there are options that include hardware in locations as wide ranging as the Martian surface and Martian orbit. While each option has pros and cons, the team concluded that reigniting Mars’ core is least feasible, and creating a plasma torus with blasted-off moon material would not significantly erode Mars’ satellites. That latter option also somewhat mimics the plasma torus created in Io’s orbit around Jupiter.

Needless to say, creating a magnetic field would require massive resources; the absolute bare minimum of power needed would be around is around 10¹⁷ joules, which was nearly the entire power consumption of all humans on Earth in 2020. That means we’ll likely need to employ nuclear fission reactors as a power source, which team speculates would likely be required for permanent colonization anyway. Among folks looking toward permanent colonies is SpaceX CEO Elon Musk — who seems to believe we don’t have a lot of time before Earth isn’t habitable — and who’s also speculated about terraforming the Red Planet. Although the authors caution that they aren’t saying a magnetic field is necessary for life on Mars, it seems pretty difficult to imagine a sustainable Martian presence without it. And it’s intriguing, to say the least, that NASA’s chief scientist is on board.”

How to Give Mars an Artificial Magnetosphere
by Brian Koberlein  /  Novermber 19, 2021

“Terraforming Mars is one of the great dreams of humanity. Mars has a lot going for it. Its day is about the same length as Earth’s, it has plenty of frozen water just under its surface, and it likely could be given a reasonably breathable atmosphere in time. But one of the things it lacks is a strong magnetic field. So if we want to make Mars a second Earth, we’ll have to give it an artificial one. The reason magnetic fields are so important is that they can shield a planet from solar wind and ionizing particles. Earth’s magnetic field prevents most high-energy charged particles from reaching the surface. Instead, they are deflected from Earth, keeping us safe. The magnetic field also helps prevent solar winds from stripping Earth’s atmosphere over time.

Early Mars had a thick, water-rich atmosphere, but it was gradually depleted without the protection of a strong magnetic field. Unfortunately, we can’t just recreate Earth’s magnetic field on Mars. Our field is generated by a dynamo effect in Earth’s core, where the convection of iron alloys generates Earth’s geomagnetic field. The interior of Mars is smaller and cooler, and we can’t simply “start it up” to create a magnetic dynamo. But there are a few ways we can create an artificial magnetic field, as a recent study shows.

“A torus of charged particles could give Mars a magnetic field”

Ideas for generating a Martian magnetic field have been proposed before, and usually involve either ground-based or orbital solenoids that create some basic level of magnetic protection. In the TV series *The Expanse*, you can see a couple of scenes where you catch a glimpse of them. While this latest study acknowledges that might work, it proposes an even better solution. As the study points out, if you want a good planetary magnetic field, what you really need is a strong flow of charged particles, either within the planet or around the planet. Since the former isn’t a great option for Mars, the team looks at the latter. It turns out you can create a ring of charged particles around Mars, thanks to its moon Phobos.

Phobos is the larger of the two Martian moons, and it orbits the planet quite closely. So closely that it makes a trip around Mars every 8 hours. So the team proposes using Phobos by ionizing particles from its surface, then accelerating them so they create a plasma torus along the orbit of Phobos. This would create a magnetic field strong enough to protect a terraformed Mars. It’s a bold plan, and while it seems achievable the engineering hurdles would be significant. But as the authors point out, this is the time for ideas. Start thinking about the problems we need to solve, and how we can solve them, so when humanity does reach Mars, we will be ready to put the best ideas to the test.”

Reference: Bamford, R. A., et al. “How to create an artificial magnetosphere for Mars.” Acta Astronautica 190 (2022): 323-333.



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