We are in the midst of a new era in space exploration, one in which everyone from NASA to Elon Musk‘s SpaceX have expressed interest in the idea of sending humans to Mars and even establishing permanent settlements on the red planet.

But one major challenge to long-term colonization of Mars is the planet’s lack of a strong, global magnetic field like that of Earth’s. In a new paper, published in the journal Acta Astronautica, an international team of scientists consider how creating an artificial magnetosphere around the planet might be possible.

While this concept may sound totally outlandish, the team—which includes two NASA experts and one from Princeton University—explore how it could be done, in theory.

“If humanity is ever to consider substantial, long-term colonization of Mars, the resources needed are going to be extensive,” the authors wrote in the study. “For a long-term human presence on Mars to be established, serious thought would need to be given to terraforming the planet.

“One major requirement for such terraforming is having the protection of a planetary magnetic field—which Mars currently does not have. In this article we explore comprehensively for the first time, the practical and engineering challenges that affect the feasibility of creating an artificial magnetic field capable of encompassing Mars.”

The Earth’s magnetosphere helps protect the planet from cosmic rays—high-energy particles that move through space at nearly the speed of light. It also enables our planet to retain its atmosphere, which would otherwise be stripped by large solar storms as they pass us by.

While Mars does have small regions where a surface magnetic field remains, these areas are confined to the southern hemisphere of the planet and are not large or powerful enough to provide sufficient protection for any future colony.

In the new paper, the scientists don’t argue for the need to create an artificial magnetosphere on Mars, or discuss the likelihood of humanity colonizing Mars, they simply outline the pros and cons of the different potential engineering approaches.

“With a new era of space exploration underway, this is the time to start thinking about these new and bold future concepts and to begin filling strategic knowledge gaps,” the authors wrote.

The researchers present multiple technological solutions for generating an artificial magnetic field on the red planet under the assumption that the desire is to create one similar to that found on Earth. They include information about where the potential magnetic field generator could be located as well as possible construction strategies.

“This issue, of creating an artificial structure at unprecedented scale, has not been considered in a peer-reviewed journal before,” the authors wrote.

Among the options considered, the researchers discuss the possibility of restarting Mars’ iron core, perhaps using nuclear weapons.

Earth’s magnetic field originates within our planet’s iron core as a result of a dynamo effect—the process through which a rotating, convecting and electrically conducting fluid can maintain a magnetic field. But the interior of Mars is smaller and cooler, thus restarting the dynamo process in the planet’s interior would be very difficult, according to the authors.

The researchers conclude that it is unlikely this will ever be a viable option given the vast numbers of nuclear weapons that would be required—not to mention other issues such as major challenges regarding drilling to the core—and the uncertainty over whether or not the dynamo effect would even restart, and how long it would continue, if so.

Another option, which has been proposed before, could involve using a vast ground-based or orbital solenoid loop system. Solenoid loops are long, thin loops of wire, often wrapped around a metallic core, that produce a magnetic field when current is passed through them.

But this approach would require the construction of a huge physical structure in space that, depending on the material used, could be very heavy and involve large quantities of rare substances. The power requirement would also be large, but not unimaginably so, the authors said, especially if controlled nuclear fusion has been successfully developed as an efficient energy source in the future.

In the end, the scientists propose what they say is a “completely novel” solution, which they deem to be the best approach for creating an artificial magnetic field around the red planet.

This solution would involve the creation of an artificial ring of charged particles around the planet, possibly by ionizing matter on the surface of one of Mars’ moon’s, Phobos. Ionization refers to the process of converting an atom or molecule into an ion—one that has a positive or negative electric charges as a result of having lost or gained one ore more electrons.

After the matter from Phobos’ surface has been ionized, these charged particles would then be accelerated to create a ring-shaped cloud of ions around Mars. A similar, naturally occurring effect has been observed at Jupiter’s moon Io.

The researchers argue this approach would create a persistent magnetic field strong enough to protect a terraformed Mars. It would also require the lowest amount of power and would involve the least mass and construction effort, they said.

Nevertheless, the researchers note that the resources needed to enact any of the solutions they described would be “vast,” while each approach will come with huge technical challenges.

The experts did not consider specific timescales and logistics in the paper, given that they expect the terraforming of Mars to be a “multi-century” endeavor.

They add that certain “paradigm-changing” shifts, such as the development of successful and efficient nuclear fusion reactors, would likely be necessary to enable the colonization and terraforming of the red planet on such a scale. But as of this time, a viable, commercial fusion reactor has yet to be developed.

The planet Mars
Stock image showing the planet Mars. Would it be possible to create an artificial magnetic field around the red planet to aid human settlements?
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