Before we explore the nuts and bolts of COSMIC, it helps to know a few details about the Earth's atmosphere that most of us learned in school but may have forgotten. The atmosphere is not too different from a multi-layer birthday cake, with each layer sitting atop the next, except that inhaling air in the atmosphere won't often give you a stomachache. Also, the dividing lines between atmospheric layers are not nearly as well-defined as layers of creamy chocolate frosting. The lowest level of the atmosphere is called the troposphere. It consists of the air that we breathe every day and is where most of the events we associate with weather take place. This layer goes from the ground up to around 6.2 miles (10 kilometers) above the Earth's surface.
Above that sits the stratosphere, which stretches from approximately 6.2 to 20 miles (10 to 30 kilometers) above the Earth. Originally thought to be very stable, air warming or cooling in the stratosphere is now known to cause significant changes in weather patterns in the troposphere, making this area an extremely worthwhile subject to study [source: Yalda].
The last thing we need to know about is the ionosphere, which consists of the ionized, or charged, particles in the upper atmosphere starting around 50 miles (80 kilometers) above the Earth. Intense solar radiation at this altitude dislodges electrons from molecules in the air, electrifying the atmosphere [source: UCAR]. If you've seen the aurora borealis, you've seen the ionosphere in action.
Now that we have a better understanding of what COSMIC is looking at, let's explore the instruments it uses to get the best view.