 Christmas is a time for celebrating with family and loved ones. Even if it's not religious, it's just the time of year where you get together with the people that you love. But for space nerds, Christmas time will always be reminiscent of Apollo 8. Apollo 8 launched on December 21st of 1968, and it was, by all accounts, a bit of a Christmas miracle of a mission. After losing three astronauts Gus Grissom, Ed White, and Roger Chaffee in the Apollo 1 fire on January 27th of 1967, NASA was forced to drastically revisit its spacecraft. There were so many problems found with the Apollo command module that the agency had to seriously revise its spacecraft, and this put everything on a delayed schedule for landing a man on the moon by the end of the decade. But NASA management found some pretty interesting and clever ways to make up for lost time, one of which was all-up testing. Instead of testing the Saturn V rocket in stages and then adding those stages together before a launch, NASA had Werner von Braun and his team launch the Saturn V all up all in one go. This was the Apollo 4 launch, and it paid off. The rocket worked beautifully, and this helped NASA regain some lost time. But in addition to revising the command module, the lunar module was also falling badly behind schedule, and so NASA made a decision. If the lunar module wouldn't be ready to fly in Earth orbit before going to the moon, why not go to the moon with just the command service module? And so the plan changed. The first manned mission for Apollo would be Apollo 7, and it would test the command service module as revised after the fire in Earth orbit. If it worked, then NASA would take the same spacecraft, just the command service module, all the way to the moon. This would be a chance for a crew, as well as the men in mission control, to figure out all the details of a lunar mission with the simpler profile of not actually having a second spacecraft to deal with the lunar module or landing on the moon. But it would really be a great test for the command service module and prove that that mothership spacecraft, the one that would support the crew for the duration of the mission and bring them back through the atmosphere to a safe splashdown, was really up to the task of getting to the moon and bringing them home. Of course, it wouldn't be enough to just go to the moon. Apollo 8 was going to go into lunar orbit, proving that the service module's propulsion system, that big engine that would propel the spacecraft in space on a mission, was able to relight at those key moments in flight, putting the spacecraft in lunar orbit and getting it out of lunar orbit back towards the Earth. And so Apollo 8 launched with just a command service module and a dummy lunar module as ballast. Most of the way to the moon, the crew couldn't actually see their target. That's because the spacecraft was just not oriented in the right direction. They didn't get their first look at the moon until they were there, on December 24th. And that Christmas Eve, they did a live TV transmission from lunar orbit. Each of the astronauts on board made some observations about the moon. Command module pilot Jim Lovell was struck by the vast loneliness, something that made him realize just what he had back on Earth. Lunar module pilot Bill Ander saw the sky as a forbidding and foreboding expanse of blackness. Commander Frank Borman saw the moon as a vast, lonely, forbidding expanse of nothing. And it was during this live TV transmission that the crew famously and somewhat controversially read from the book of Genesis, live to the United States and the world. But for all the firsts accomplished on Apollo 8, perhaps the most incredible is that this was the first time humans ever saw the Earth rising above the horizon of the moon. And it wasn't just the crew who saw it. They took this iconic picture to share it with the rest of the world.