FILE - In this April 11, 1970 file photo, the Saturn rocket carrying the Apollo 13 spacecraft lifts off the launch pad at Cape Kennedy, Fla. It really is rocket science and it really is hard. North Korea proved that again. The giant explosion that gets a rocket off the ground isn't that complicated. Controlling that reaction and going where you want, when you want - that's where engineers earn their money and ulcers. And it's where past rockets and spaceships have ended in spectacular and sometimes deadly failures. Former NASA deputy administrator Hans Mark said most failures are from human error. He pointed to a dropped oxygen tank that caused the near-fatal Apollo 13 explosion. (AP Photo)
Apollo moon rocket engines recovered
Long thought to be lost forever on the ocean floor, Saturn V's massive engines that
launched astronauts to the moon more than 40 years ago have been
recovered by a private expedition led by Amazon CEO Jeff Bezos.