A lightning rocket is a
rocket
A rocket (from , and so named for its shape) is a vehicle that uses jet propulsion to accelerate without using any surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely ...
that unravels a
conductor, such as a fine
copper wire, as it ascends, to conduct
lightning
Lightning is a natural phenomenon consisting of electrostatic discharges occurring through the atmosphere between two electrically charged regions. One or both regions are within the atmosphere, with the second region sometimes occurring on ...
charges to the ground. Lightning strikes derived from this process are called "triggered lightning."
Design
A conducting
lightning rod
A lightning rod or lightning conductor (British English) is a metal rod mounted on a structure and intended to protect the structure from a lightning strike. If lightning hits the structure, it is most likely to strike the rod and be conducted ...
is grounded and positioned alongside the launch tube in communication with the conductive path to thereby control the time and location of a lightning strike from the thundercloud.
The conductor trailed by the rocket can be either a physical wire, or column of ionized gas produced by the engine. A lightning rocket using solid propellant may have cesium salts added, which produces a conductive path when the exhaust gases are discharged from the rocket. In a liquid propellant rocket a solution of calcium chloride is used to form the conductive path.
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 and follow the ionization trail of the initial strike. Rockets of this type are used for both lightning research and lightning control.
Betts system
The Betts ''lightning rocket'', patented by Robert E. Betts in 2003, consists of a
rocket
A rocket (from , and so named for its shape) is a vehicle that uses jet propulsion to accelerate without using any surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely ...
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.
[{{cite web , title=US6597559B2 Lightning rocket , url=https://patents.google.com/patent/US6597559 , website=Google , access-date=13 July 2021] This system is designed to control the
time
Time is the continuous progression of existence that occurs in an apparently irreversible process, irreversible succession from the past, through the present, and into the future. It is a component quantity of various measurements used to sequ ...
and the
location of a
lightning strike
A lightning strike or lightning bolt is a lightning event in which an electric discharge takes place between the atmosphere and the ground. Most originate in a cumulonimbus cloud and terminate on the ground, called cloud-to-ground (CG) lightning ...
. As the rocket flies to the thundercloud a 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.
References
External links
July 25, 2002, triggered lightning videoTransient Response of a Tall Object to Lightning
Lightning