I watched Armageddon again fairly recently with Bruce Willis, oil drillers in space and an asteroid the size of Texas bearing down on Earth. Buried beneath the Hollywood chaos is a genuinely interesting question: What exactly could we do with an asteroid if we got our hands on one? As it turns out, the answer has nothing to do with blowing it up, sorry Bruce, but everything to do with building a new world.

Building a colony on Mars is not just an engineering problem, it's a logistics one too. The logistics, unglamorous as it sound, may ultimately determine whether humanity becomes a multi-planetary species or stays firmly rooted on Earth.

▶ Don't miss: Snowball Earth may hide a far stranger climate cycle than anyone expected

Think about what a Mars colony actually needs. Not just food and oxygen, but metal. Structural steel for habitats, aluminum for equipment, iron for tools and many of the components will wear out, break, and need replacing. Shipping all of that from Earth every time is not a serious long-term strategy. A rocket launch costs tens of millions of pounds per ton of cargo, and the journey to Mars takes between six and nine months depending on where the two planets happen to sit in their orbits. You cannot run a hardware store on that kind of supply chain.

A new study from researchers at EPFL in Switzerland posted to the arXiv preprint server has now done the hard math on mining asteroids and delivering the metals directly to Mars. The solar system contains millions of asteroids, and the metallic ones, known as M-type asteroids, are essentially giant lumps of iron, nickel, and other valuable materials floating through space. The question is whether we can actually reach them, extract what we need, and get it to Mars efficiently enough to make it worthwhile.

The answer, it turns out, is a careful yes but with conditions.

The team ran a computer program that tests thousands of different combinations to find the best possible answer across multiple supply chains. They took into account the energy required to travel between different asteroids and Mars, the mass of metals that could realistically be extracted, and, crucially, the fuel needed for the return journey.

That last point is where a clever twist enters the picture. Some asteroids are carbonaceous, they are rich in carbon and water ice. Process those materials correctly and you can manufacture rocket propellant right there in space, eliminating the need to carry return fuel from Earth. The study builds this possibility directly into the supply chain calculations.

The results identify specific asteroids that sit within reach of current spacecraft technology, where the energy cost of getting there and back is low enough to make the mission viable. The team soon learned that selecting the right targets is everything. A poorly chosen asteroid could consume more fuel than the value of the metals it delivers.

What makes this study significant is not that it solves the problem, because we are still a long way from the first asteroid mining operation. Instead it's that it demonstrates the problem is 100% solvable. A supply chain delivering metals from space to Mars, fueled by propellant manufactured on the asteroids themselves. The colony on Mars will need builders. It will also need someone to sort out the deliveries and this study shows it can be done.