 Greetings and welcome to the Introduction to Astronomy. In this week's Exploration of the Solar System, we are going to look at the first few Vanira spacecraft, those numbered 1 through 4. Now the Vanira spacecraft were our early explanation of the planet Venus, our nearest planetary neighbor in space. So we've looked previously at exploration of our Moon, which is even closer, but now we're looking at a planet for the first time. And in fact we'll see the first few Vanira spacecraft, Vanira 1, 2, and 3, were actually unsuccessful. Well the first one, Vanira 1, launched in 1961, communications were lost after about a week, it did fly by Venus, but of course no information was able to be returned. There was a successful fly by in February of 1966 by the Vanira 2 spacecraft, which was launched at the end of the previous year, and however communications were turned off for the fly by so that images could be recorded and no contact was then re-established. So we can see a sample of one of those craft here that was used. Now Vanira 3 was launched about the same time as Vanira 2, just a couple of days later, and it was scheduled to be a crash landing on the surface of Venus. Now we'd previously crashed on the surface of the Moon in our early explorations of the Moon, so here was a chance to actually crash on the surface of a planet. That did happen on March the 1st of 1966, but contact had been lost several weeks before. So really the first successful mission that actually did what it was trying to do was the Vanira 4 spacecraft, and that was launched in June of 1967, and it was designed to study the atmosphere and again to crash on the surface, and here we see a mock-up of that impactor that was going to crash into the surface. Now this was successful as it was able to return information about the atmosphere. So it was not a successful landing on the surface, although it would have crashed into the surface eventually, but we started to learn something about the atmosphere of Venus, and this was our first real look into how this might be. And we started to find that Venus was much different than we expected, and in fact there were many thoughts prior to this that Venus might be a watery world beneath all of those clouds, but here we've begun to learn about the high pressures and the intense amount of high amounts of carbon dioxide in the atmosphere. So we're learning now beginning to learn that Venus is going to be a very inhospitable place and not a very easy place to land. We were getting very high pressures when the craft ceased signalling, and again had gotten our first measurements of the atmosphere direct study as a craft traveled through the atmosphere of another planet for the first time. So let's go ahead and summarize a little bit about what was done here. The first four Venera spacecraft were some of the earliest craft to explore the planet Venus. The first three were at least partially or completely unsuccessful, but Venera IV did give us the first direct study of the atmosphere of another planet beyond our Earth. So that concludes this discussion of the first four Venera spacecraft. We'll be back again next week for another topic on exploration of astronomy. So until then, have a great day everyone, and I will see you in class.