Scientists may have discovered a way to create oxygen on Mars, a crucial step toward long-term colonization.

Interest in colonizing Mars has increased in recent years. Many, including Tesla and SpaceX’s Elon Musk, believe the human race needs the kind of insurance policy a second planetary home would provide. Especially as climate change has become a bigger threat, many believe it’s vital to colonize other planets. Musk has even said he’s confident SpaceX will send humans to Mars in roughly six years.

One of the biggest challenges to long-term colonization, however, is oxygen generation. Without a native method to produce oxygen on Mars, any colonization efforts would be limited by the quantity of oxygen that could be brought on resupply missions.

Scientists believe they have discovered a solution, however. NASA is currently working with MOXIE (Mars Oxygen in Situ Resource Utilization Experiment) to convert carbon dioxide in the Martian atmosphere to oxygen. MOXIE operates along the same principle as trees on Earth.

According to CNN, however, scientists at Washington University in St. Louis have come up with a method they believe will compliment MOXIE and provide a second source of oxygen. The new method, proposed by Professor Vijay Ramani and his colleagues, uses salty water to generate oxygen.

Despite its red desert appearance, Mars has quite a bit of ice. In addition, there appears to be a salty lake, along with a number of ponds, under the southern icecap.

“The presence of the brine is fortuitous because it lowers freezing point of the water. You take the salty, brackish water and electrolyze that. Our process takes the water and splits it into hydrogen and oxygen,” Ramani said.

While some NASA personnel are doubtful the process will work, due to the frost point on Mars, it appears there are no shortage of possibilities for generating oxygen on Mars. That’s one less hurdle to long-term colonization.