The distance between Mars and Earth is constantly changing due to the Earth's orbit, but they come closest to each other every 26 months, when the distance between them is only 80 million kilometers. :) With the current gear technology, this distance is approx. 9 months, but the current technology is already 50 years old, so the performance isn’t too steep. If I heard right, there are ion engines under development that could reduce this time to as much as 76 days because a spacecraft would be able to reach speeds of 40,000 km / h.