The concept isn't as far-fetched as it sounds. There's already research into inflatable structures that would create the mini-magnetosphere you'd need for this to work. The biggest challenge, as with many things in space, is time. While a shield would have a relatively rapid effect on radiation, it's not certain how long it would take to thicken the atmosphere and increase temperatures. A magnetic shield would amount to a kind of terraforming, after all, and even a relatively quick change could take decades. NASA and SpaceX would still have to visit a hostile planet in the years ahead.

Still, the very fact that this is even on the table is noteworthy. It suggests that it would be realistic to preserve and even improve Mars' remaining atmosphere without the staggering effort that would be needed to directly alter the planet.