NASA Technical Reports Server (NTRS) 20020062189: Lightning Detection in a Flash

1 Pages·0.09 MB·English

by  NASA Technical Reports Server (NTRS)

Lightning Detection in a Flash
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hunderstorms may always remain an erratic and The new product, known as LDAR II, is targeted for use E
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unpredictable force of nature. Unfortunately, when by utility providers, aviation companies, airports, and IA
lightning strikes serious damage can occur. This risk commercial space vehicle launch facilities. Presently, forecast- L B
must be thoroughly analyzed and precautions must be ing services, research facilities, and a utility company are using EN
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taken—especially when multi-million dollar vehicles, such as the system. Weather forecasting services use LDAR II to view F
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Space Shuttles, are at risk. In a joint project with NASA’s the height and horizontal extension of each lightning flash. S—
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Kennedy Space Center, Global Atmospherics, Inc. (GAI), The LDAR II antenna consists of a fiberglass lightning mast P
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participated in the upgrade and commercialization of the containing signal processors that provide data to a computer. O
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Lightning Detection and Ranging (LDAR) System. Under a The user can then interpret the data, analyze the risks, and F
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Space Act Agreement, GAI and Kennedy agreed to the joint take the necessary precautions.
development of a new LDAR system that meets the needs of There are obvious safety
both NASA and private industry. benefits associated with the
Kennedy Space Center averages 75 thunderstorm days per use of LDAR II. Annually,
year, so lightning warnings are nothing new, especially in the lightning kills more Florida
hot, humid months of summer. NASA needed a system that citizens than any other
could minimize unnecessary warnings and maximize work weather hazard. It is hoped
productivity without sacrificing the safety of its personnel and that the widespread use of
projects. The resulting development was a volumetric the LDAR systems will
lightning mapping system. reduce this sort of tragedy.
NASA operates a three-dimensional LDAR system capable For example, the National
of determining the exact location and altitude of in-cloud and Weather Service used the
cloud-to-cloud lightning. This is done through the analysis of technology to assist with
the exact arrival times of electromagnetic pulses. The times weather forecasts during
are collected using seven antennae stationed around the the World Olympic soccer
region that detect VHF radiation. The collected data is then tournaments held in
analyzed, geo-located in three dimensions, and transmitted to Orlando, Florida, during
the Weather Squadron, 45th Space Wing, Patrick Air Force the summer of 1996.
Base, Satellite Beach, Florida, and to the National Weather Without the projective
Service personnel at Johnson Space Center, Texas and in capabilities of the LDAR
Melbourne, Florida. They use the data to define the existence system, thousands of
and volumetric extent of the potential lightning hazard for spectators could have been
the space program and Central Florida. GAI was able to see placed in the path of
the numerous opportunities and applications of a system that serious injury with no
could provide accurate projections of lightning patterns in forewarning of a possible
almost real-time, and made a good thing better. lightning strike. From the
GAI is the world’s largest manufacturer of lightning protection of people to
detection and location equipment, providing service to space vehicles, electric
customers in over 40 countries. They also serve as owner and companies to launch pads,
operator of the U.S. National Lightning Detection Network GAI and NASA created a
(NLDN). While the NLDN is able to plot the strike locations technology full of safety
of each cloud-to-ground flash, it does not locate in-cloud and and operational benefits. ❖
cloud-to-cloud flashes.
Under the Space Act Agreement, GAI contributed its
wealth of experience and resources to update and improve the
current lightning mapping system used by NASA. Previously,
The LDAR II fiberglass
commercial systems were only capable of locating cloud-to-
lightning mast contains signal N
ground lightning. The resulting innovations allowed GAI to A
processors that provide data to S
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position the LDAR system for commercial applications. The a computer where the user can S
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upgraded product has the ability to measure in-cloud and then interpret the extent of IN
cloud-to-cloud lightning. Notable improvements have also lightning hazard. O
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been made in the system’s location accuracy and signal ➤
detection. 2
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