 Greetings and welcome to the Introduction to Astronomy. In this week's Exploration of Astronomy, we are going to talk about the Apollo 1 mission and the beginning of the Apollo program that would eventually land humans on the Moon for the first time. Now, Apollo 1 was essentially planned to be the first of the Apollo missions with astronauts so actually being able to launch. The launch was scheduled for February 21st of 1967. Now as you know, we landed on the Moon in 1969 so we're getting pretty close here and this is just the beginnings of the Apollo mission. The idea was to be able to test the command module for future Moon flights. Now what happened is before that there was a launch rehearsal on January 27th of 1967 and there was a big problem there and in fact a cabin fire that ended up killing three astronauts. So the cabin fire ended up destroying the command module and killing the three astronauts pictured here Gus Grissom, Ed White, and Roger Chafee. Now determination later was that there were definitely some problems with this. It was an electrical fire and the cabin was pressurized oxygen so pure oxygen under high pressure gave a very rapid spread to the fire that occurred. So it ended up completely burning out the module as we can see here in this picture taken afterwards. And because the cabin was pure oxygen that really helped the fire to spread fast and was very quickly overwhelmed the astronauts. So it turned out they could not even get out because of the pressurized hatch and that could not be open so there was no way for them to get out as it was and eventually or quickly their suits were damaged by the fire and they would have asphyxiated in the chemicals that were being burned within that within the lunar command module. Now after this of course as you might expect crewed missions were suspended for a year and a half. So as you'll see that gets us pretty close to the Apollo 11 mission that landed humans on the moon for the first time and that was to investigate this disaster. What had to figure out what the problems were. I've mentioned a little bit about those right here as to what happened and to be able to figure out what could be done so that such a disaster did not happen again. And as we will see that took a while to investigate we took about a year and a half. Now the Apollo mission did not stop as we'll see in future lectures. The Apollo mission continued. So there were certainly uncrewed launches that occurred during this investigation. But all of the crewed missions were suspended until 1968 when they began again as we'll see those with some later missions as well again once they were able to figure out the details of exactly what happened here. And of course in hindsight looking back we can see some of the problems that were set up in this craft as it would have been a very dangerous situation. If something like this were to happen you get that little bit of fire within a pure oxygen atmosphere and it just spreads very very fast. So let's go ahead and summarize what happened with Apollo 1 and what we look at again it was really kind of the beginning of the program that would eventually land humans on the moon. We found that an electrical fire started within the command module during a rehearsal so this was not a launch this was not in space this was just during a rehearsal on the launch pad which destroyed the module and killed the three astronauts who were trapped inside. And the review of the tragedy allowed for fixes to be implemented for the success of the future Apollo missions that would land humans on the moon just a couple of years later. So that concludes this lecture on the Apollo 1 mission. We'll be back again next time for another exploration of the solar system. So until then have a great day everyone and I will see you in class.