NASA’s newest rover, Perseverance, produced oxygen from the Martian atmosphere. It only produced 4 grams or so, but the fact that oxygen can be produced enables supplies for astronauts and colonists to breathe, rockets to launch and return to Earth, and many of the operations we take for granted here in our oxygenated atmosphere. It was more reasonable to carry our air and fuel to the Moon, but visits to Mars will likely take weeks or months instead of the few days we spent on the Moon. A robotic oxygen factory can be flown to Mars, left to accumulate enough for the next mission, and make it easier for that mission as well as subsequent activities. One small step – that is very significant.