What is Plasma?

Plasma is called the fourth state of matter. The American Heritage Dictionary of the English Language describes plasma as "An electrically neutral, highly ionized gas composed of ions, electrons, and neutral particles. It is a phase of matter distinct from solids, liquids, and normal gases".

Why do you care about plasma?

Plasma, the state of matter in a fusion reaction, is thought to be the next great method for generating energy. Research in plasma and fusion reactors is a very current area of research in the physics realm. The web site www.howstuffworks.com explains a little more about plasma and it's uses. "Fusion can only occur in super-heated environments measuring in the millions of degrees. Stars, which are made of plasma, are the only natural objects that are hot enough to create fusion reactions. Plasma, often referred to as the fourth state of matter, is ionized gas made of atoms stripped of some electrons. Fusion reactions are responsible for creating 85 percent of the sun's energy.
"The high level of heat required to create this type of plasma makes it impossible to contain the components in any known material. However, plasma is a good conductor of electricity, which makes it possible to be held, guided and accelerated using magnetic fields. This is the basis for creating a fusion-powered spacecraft, which NASA believes is achievable within 25 years."

What does Plasma have to do with the Space Shuttle?

The space shuttle is moving so fast durring re-entry, over 30,000km/h, that a plasma is formed on the bottom of the shuttle. Contrary to intuition the extreme heat that causes the plasma does not come from the friction of the air molecules, but from the extreme pressure that is built up in front of the shuttle. This plasma actually forms a "radar jammer" during parts of the desent to earth causing communication to be lost with the space shuttle for periods of time. As long as the plasma, or extreme levels of heat from the plasema, do not get into the shuttle there will mostlikely be no serious damage to the shuttle or the crew on board due to the plasma.