A lightning rocket is a

rocket A rocket (from it, rocchetto, , bobbin/spool) is a vehicle that uses jet propulsion to accelerate without using the surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely fr ...

that unravels a conductor, such as a fine

copper wire Copper has been used in electrical wiring since the invention of the electromagnet and the telegraph in the 1820s. The invention of the telephone in 1876 created further demand for copper wire as an electrical conductor. Copper is the electr ...

, as it ascends, to conduct

lightning Lightning is a naturally occurring electrostatic discharge during which two electric charge, electrically charged regions, both in the atmosphere or with one on the land, ground, temporarily neutralize themselves, causing the instantaneous ...

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 will preferentially strike the rod and be conducte ...

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

launcher that is in communication with a detection device that measures the presence of

electrostatic Electrostatics is a branch of physics that studies electric charges at rest (static electricity). Since classical times, it has been known that some materials, such as amber, attract lightweight particles after rubbing. The Greek word for amber ...

and

ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

ic 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 continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to ...

and the

location In geography, location or place are used to denote a region (point, line, or area) on Earth's surface or elsewhere. The term ''location'' generally implies a higher degree of certainty than ''place'', the latter often indicating an entity with an ...

of a

lightning strike A lightning strike or lightning bolt is an electric discharge between the atmosphere and the ground. Most originate in a cumulonimbus cloud and terminate on the ground, called cloud-to-ground (CG) lightning. A less common type of strike, ground- ...

. 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.

References

External links

July 25, 2002, triggered lightning video

Transient Response of a Tall Object to Lightning
Lightning