Nasa 'climate change' test chamber to simulate Venus' toxic conditions The pressure is equivalent to levels experienced just over half a mile under the ocean. The chamber can handle a number of different "planetary" atmospheres but scientists say Venus was the most difficult due to its "high temperatures and high pressures and the combination of chemicals on the surface." It also has two "sapphire glass" windows at the end of each chamber that can allow scientists to observe conditions. The chamber, complete with stainless steel bolts measuring an inch in diameter and 10 inches long, also has about a million pounds of force acting on its lid. On Thursday Rodger Dyson, the Nasa engineer in charge of the project, said the experiments were important to help understand climate change. He said Venus "used to be like Earth so there is a lot of lessons for us to learn from it." "It was thought that Venus was very much like earth several billion years ago - why did it go down its path of overheating," he said. It is now 98 per cent carbon dioxide in the atmosphere. Is earth heading in that direction? The climate modelling we do on earth - people are concerned about climate change - but the problem with any of our models is that we have had troubles predicting the weather a week from now let alone trying to predict something over a 10-20 year time frame. He added: "On Venus it is a whole another experimental environment, where you have the same gravity and the same physics but you have different boundary conditions. So it is a way of verifying climate models. "There are actually people talking about sending helium balloons to Venus but the problem all along has been "how do you survive that environment" and are just getting to the point where we have technology that can allow us to do that." He said that the chamber should be able to have a "Lander" vehicle in it "so we can show it can last on the surface of Venus for about 243 days." He said scientists chose Venus because of several interesting reasons including its proximity to Earth - it can take as littler as four months in "travel time" - and its similar gravity and physics. Only 10 spacecraft have reached Venus" surface, in at least partial working order. Nine were Soviet landers while only one American surface mission launched, in 1978. The last lander sent to Venus, the Soviet Union's Venera 13, lasted only 127 minutes on the planet's surface before succumbing to temperatures of 855F and intense. "The reason this is significant for space exploration is because the last time we went to the surface of Venus was well over 20 years ago and that mission only last around 127 minutes, approximately on the surface," he told the BBC's Radio 4 programme. So two hours is about the longest we have been able to have anything survive there. Quite frankly 20 years ago we didn't know what the atmosphere was made of or really just how hostile a place it really was. He added: "Now if you want to go back there, it is about a $1 billion to go back and do a mission, so you really don't want spend just a couple of hours (there) you want to spend ideally a whole year." No details of the cost have been disclosed but it is expected. Experiments are due to start in May.