Dez didn ' t catch it . Side note Anger from the fanbase aside , by the applicable rule , Dez didn ' t catch it . <| sep |> NASA doesn ' t only do space travel , it mostly does space science , exploration and research . In order to know how space and all bodies in space work like planets , stars , galaxies it is best to look at those bodies that are closest to us . And Earth is , conveniently , very close to us . We can look at the Earth from all angles , from very close from the ground , from within the air and from far from satellites in low orbit , from satellites in high orbit and collect all sorts of data . This allows us to create models and similations which we can then use and modify to the much more limited data we get from other bodies and adept the models to understand how those other bodies work and , ultimately , to make predictions . So in order to understand how the atmospheres of Mars , Venus or Jupiter work , it is best to first understand how the atmosphere of the Earth works . In order to find water on Mars it helps to see what effects water have on Earth and look for similar things on Mars . In order to understand how magnetic fields of other planets work , it helps to understand first how the magnetic field of the Earth works . And there are many more examples . In order to find signs of life on other planets , or other planets that are habitable , we first need to understand what makes Earth habitable and how life influences Earth , so that we know what exactly to look for like an Oxygenrich atmosphere and liquid water . All that data we get from Earth helps other to better understand data from distant bodies , even planets around other Stars . The data we get from the Sun helps to better understand other stars . The data we get from the Milky Way helps to better understand other galaxies . Having more knowledge about all the things in the universe also helps making predictions about the future of the Milky Way , the Sun and the Earth . And that might be important for the survival of us . If we would learn that the Sun would die very soon by looking at similar stars which it doesn ' t , thankfully , we could concentrate our efforts to find other places to live on and how to get there . Or if we would learn that the Earth ' s magnetic field would die soon which it doesn ' t , thankfully we would know from Mars what that means losing most of the atmosphere , losing most of the liquid water , getting bombarded by radiation from the sun . And that ' s also the same with climate research . Researching climate helps to better understand other planets , but also our own , and ultimately it can help to detect and prevent dangerous changes . Last , but not least , a very good place to study the Earth ' s atmosphere , weather and climate is from satellites in space . So NASA has many reasons to study Earth climate and they have many satellites specifically for that purpose , both to better Earth itself and and other planets . So without studying , trying to understand and predict Earth climate they couldn ' t do space research , which is one of their purposes .