 Greetings and welcome to the Introduction to Astronomy. In this week's Exploration of the Solar System, we are going to look at the Venera 5 and 6 craft, which continued our study of Venus. So let's see what we have learned here. And what we see is that Venera 5 and 6 were launched pretty much at the same time. Venera 5 on January 5th of 1969, and Venera 6 a few days later on January the 10th, and they arrived at Venus almost at the same time even closer, one on May 16th and one on May 17th, both of 1969. The idea of these craft was to explore the atmosphere of Venus. So we want to look at the surface, but as we began to study Venus we found out that it is a very inhospitable atmosphere, and many of the things that had been found was that it had extremely high temperatures and pressures, and very corrosive substances in the atmosphere, making it very difficult. So these were kind of intermediate stages to try to be able to explore more of Venus. They would use a parachute to slow down their descent through the atmosphere, and knowing how thick the atmosphere was, the parachute could be adjusted to allow for the maximum amount of time for the craft before it eventually became destroyed as it got too close or too far down into the atmosphere of Venus. These were able to study the composition of the atmosphere in more detail than previous observations, and the craft were improved to be able to give a longer survival time under the extremely harsh conditions that exist in Venus. How long was that? Well these craft survived about 50 minutes each, less than an hour. So even though it was more than had been done before, it still was not a very long time. We're finding that the conditions on Venus are very inhospitable to the craft that we send there, and those craft do not survive very long. What do we find? We find again, high temperatures, extremely high temperatures, and we have not made it down to the surface yet, and it will get hotter and hotter. High pressure is much higher than anything we have on Earth, and extremely high levels of carbon dioxide. And we'll see of course that that carbon dioxide is related to the very high temperatures through the greenhouse effect. Carbon dioxide is not just a small fraction of a percent of the atmosphere in Venus as it is on Earth, it is actually the vast majority of the atmosphere making up more than 95% of the atmosphere. However, the information that was gained here was helpful in terms of preparation for future landings on Venus that we will see with future Venera craft that were actually able to make it through the atmosphere and land on the surface and give us to date our only images of the surface of Venus that were taken directly from the surface. So let's go ahead and finish up with our summary, and what we've looked at again is Venera 5 and 6 were designed to study the atmosphere of Venus. They were improved from previous craft for longer survival by building on those previous findings learning what we knew about Venus and adjusting the craft to be able to survive longer under those conditions, and this led the way for future landings on the surface of Venus. So that concludes this lecture on the Venera 5 and 6 spacecraft. 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.