Monday, September 20, 2010

Model rockets used to attract lightning

"The Betts lightning rocket patented in 2003 consists of a rocket launcher that is in communication with a detection device that measures the presence of electrostatic and ionic change in close proximity to the rocket launcher that also fires the rocket. This system is designed to control the time and the location of a lightning strike. A lightning rocket can have solid propellant that has cesium salts added which produces a conductive path when the exhaust gases are discharged from the rocket that is expelled to the static layer of a thundercloud. A conducting lightning rod which is grounded and positioned alongside the launch tube for the solid propellant is in communication with the conductive path to thereby control the time and location of a lightning strike from the thundercloud. In a liquid expelled rocket a solution of calcium chloride is used to form a conductive path from a thundercloud. As the rocket flies to the thundercloud this liquid is expelled aft forming a column in the air of particles that are more electrically conductive than the surrounding air. In a similar fashion to the system employing a solid propellant as the conductive producer this conductive path conducts a lightning strike to ground to thereby control the time and location of a lightning strike from the thundercloud.

The traditional lightning rocket by comparison is simply a rocket (generally about the size of a man) that has a fine copper attached to conduct the electrostatic charge to the ground. The system consists of a specially designed launch pad with lightning rods and conductors attached. The launch pad is either controlled wirelessly or via pneumatic line to the control station to prevent the discharge traveling to the control equipment. The fine copper wire (more recently reinforced with kevlar) is attached to the ground and plays out from the rocket as it ascends. The initial strike follows this wire and is as a result unusually straight. As the wire is vaporized by the initial strike subsequent strikes are more angular in nature following the ionization trail of the initial strike. Rockets of this type are used for both lightning research and lightning control."

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