can take seven months – or more – to get to Mars. NASA can send supplies to the International Space Station if need be, but the same isn’t true of the distant planet. Instead, astronauts spending any time on Mars will have to rely on what’s known as in-situ resource utilization (ISRU) – using what’s around to replace objects brought from Earth. That includes food, which will eventually have to be grown there, to support any long-term residents. Instead of hauling bags of fertilizer in the spacecraft, researchers are trying to figure out how to make do with what’s on the ground, that is, Martian soil. Thanks to NASA’s rovers and landers, scientists know about the pH and mineral makeup of the planet’s soil, which is known as regolith. Mars gets its red color from the oxidation of its rocks, regolith, and dust. Below the dust is the crust, which contains iron, magnesium, calcium, potassium, and more elements, according to NASA . But their presence isn...