 Greetings and welcome to the Introduction to Astronomy. In this week's Exploration of the Solar System, we are going to look at the Luna 4-9 spacecraft and continuing the study of our moon. So it's a lot of spacecraft to look at there, we've got six spacecraft to discuss, but we're going to see there's not a lot to say about them. So let's look at a few of these. First of all, the Luna 4 and 6 were launched in April of 1963 and June of 1965. They both had failed course corrections and missed getting to the moon. Luna 5, 7, and 8 were launched in May, October, and December of 1965. These were attempts at soft lunar landings, actually a soft landing on the moon. And as you can see here, the retro rockets failed in these cases and they were unsuccessful. Did they land on the moon? Yes. Did they soft land on the moon? Definitely not. Although you can see labeled over here in our image some of the, one of the regions where the Luna 8 would actually have landed. So it would have crashed into the surface of the moon at that location. Now we also have the Luna 9 spacecraft and that's the one we really want to look at here. So first of all, we see its landing site here labeled on the moon and we can also take a look at a mock-up of one of these craft that is shown here in a museum, one of the first craft, again to land on the moon. Now Luna 9 was launched in January of 1966 and it was the first craft to successfully soft land on any other celestial object, in this case our moon. And it landed on February 3rd of 1966. Now this gave us the very first time that we could ever see another craft, an object landing on the surface of another world and we can also see the very first image here, one of the very first images from Luna 9 showing us what the surface of the moon looked like taken from the surface. Now we'd certainly had previous observations from orbit and we could see images of the moon but this is the first time we had ever taken a picture from the surface of any other celestial object and of course as we work our way through we'll see far more but it is very interesting to see the first here. Now this also demonstrated that we could actually successfully land on the moon. Why would we think that would be such an issue? Well we didn't know for sure before landing what the lunar soil was like and how thick it would be and we know now that the lunar surface is covered with a powdered rock that has been fragmented from billions of years of micrometeorite impacts and we did not know how deep this would be and if the craft would just sink into it if it was too deep of a surface and that was very important for future manned landings on the moon because you wanted to make sure that that craft was going to be on the surface and would be able to take off again. So not only did we get the first images from the surface of another world with Luna 9 we also showed that it was able to successfully land a craft on the surface of the moon as well. So let's go ahead and summarize here and what we've looked at are we talked about the five of these lunar craft Luna 4 through 8 all had issues two missed the moon completely two crashed into the moon instead of soft landing. Luna 9 was the successful one and really gave us the first images taken from the surface of another celestial object and told us that we could be able to land a craft on the surface of the moon. So that concludes this lecture on the Luna 4 through 9 spacecraft. We'll be back again next week for another video on the exploration of the solar system So until then have a great day everyone and I will see you in class!