Perseverance, the Mars explorer, made landfall Thursday. The module landed on target in Jezero crater, 30 miles across, 300 million miles from Earth. Let me put that in perspective. Imagine you are teeing up at hole one of your favorite golf course. You select your club and take aim at the hole, a cozy 195 miles away. If you could launch a golf ball that distance, the size of the hole would be proportionately the same size as the target Perseverance was aiming at. The target was also revolving around the sun at around 55,000 miles an hour, while you and your tee were spinning at closer to 77,000 mph. Oh, sure, the rocket soaring across the millions of miles could make course corrections — but if those corrections were off-target by as much as a foot per mile from launch, Perseverance would miss the landing by nearly 57,000 miles. Quite literally, there was absolutely no margin of error for the rocket to land successfully on Mars.