Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt ASRC Aerospace Electrical...

Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt

ASRC Aerospace

Electrical Discharges in the Upper Atmosphere and Its Effects on

Near Space Vehicles

Cindi Schmitt, Ph.D.

ASRC Aerospace Corporation26 April 2007


ASRC Aerospace

• Overview• Ground protection and vulnerability aspects.• Recap of electrostatic discharge types and discharge energy events

from lightning and static charge build-up.• Video• Why lightning mapping is crucial for NS platform development and

CONOPS development - where we want to use them CONUS and OCONUS are exactly where lightning strikes predominate.

• SBIR research status: MDA Phase I and current Phase II investigation

• Summary• Back up slides

Slide 1

Contents


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Large towers can be used to protect against direct lightning strikes and also to minimize the effects of indirect damage. The susceptibility is larger on vehicles without a metal skin, such as high altitude airships and high altitude balloons, due to the lack of a “Faraday cage”.

Ground Lightning Strike MitigationNot the same when it's flying…

Slide 2


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Atmospheric Electrical Discharges

Slide 3

Why is electrical discharge of concern for near space platform development?

Because:Systems and subsystems behave differently when

subjected to electrical discharges. Induced voltages and currents could negatively affect the operation of

electronics: static discharge is the number one cause of sudden, unexpected failures

http://gpsinformation.us/humor/Lightening.htmlAl Nippon Airliner, Osaka, Japan 2005

Nov. 19, 1969, Apollo 12 was struck twice by lightning in the 36.5 seconds after liftoff.1.8 km (6,000 ft) off the ground.

"…numerous evidences of electromagnetic surge on TWA Flight 800 plane wreckage…"Ian Goddard, March 12, 2001 http://www.geocities.com/CapeCanaveral/Cockpit/3240/awst1.htm

Indirect effects, caused by the electromagnetic radiation from a lightning strike, can result in vehicle damage


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Multiple strikes from one discharge. Whether you can see them or not…

Examples of Strikes and Vulnerability Aspects

Slide 4

STS-55

Florida 2005


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Why Study Lightening Effects on Flight Vehicles?

Buildup of strong electric fields at certain points on a platform can generate lightning bolts without the associated storm clouds as the friction from the air helps to set up these fields. Such concentrated fields of electrical energy develop before lightning occurs, which is the field attempting to bleed off the charges. When a vehicle enters into this high electric field, electrical charges are compressed concentrating around sharp edges and protuberances. If the electrical fields build up to where there is an electrical breakdown of the air, lightning leaders form at two or more locations. The vehicle itself contributes to the conducting path between a positive and a negative electrical field. It can trigger a lightning bolt in close proximity to storm clouds, or it can generate a discharge (not considered a lightning bolt).

There are 3 types of system failures triggered by electrical surges:Immediate Recoverable Latent

Why is electrical discharge a concern for vehicles within our atmosphere?Answer: Systems and subsystems behave differently when subjected to electrical discharges.

Slide 5


ASRC AerospaceSprites, Elves

and Jets

Slide 6

massive, weakluminous flashes

Tendrils extend down to 30 kms, Body of the sprite is 60 ~ 80 km.


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Video

Slide 7


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Lightning Discharge Energy

Some sprites, referred to as C-Sprites, are vertically-oriented columns 200 m wide and 10 km long.

Slide 8

Dr. Hugh Christian: "We see tremendous variations in extratropical regions," meaning areas north or south of the tropics of Cancer and Capricorn. "You see lightning activity truly following the sun. As summer in the N hemisphere progresses, you see lightning moving farther north." (Global Hydrology and Climate Center)

JUNE 20, 2006NASA Image


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Lightning and EM Hazards Protection Designs:Previous Research Provides Scientific

Basis for Further Study

Direct-effects testing at LTI's laboratory. Funded under a NASA Langley SBIR award.

Glasair III LPPrototype

FAA FAR23 Reqmts.

CL-180 1/25 model

CargoLifter CL-160 Lightning and ElectromagneticEffects (EME) protection design team:

Project Terminated in 2002

A test resulted in a puncture of the envelope:This test allowed the role of envelope materials,load cable configuration and protection design

configuration to be evaluated.

http://www.lightningtech.com/intro.html

Slide 9

MDA SBIR Phase II Prime2005 Award for Research


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Lightning and EM Hazards Protection Designs:ASRC Aerospace and NASA

ASRC Aerospace is the NASA KennedySpace Center Prime Contractor and Consultant for lightning mitigation.

Currently, ASRC Aerospace personnel aredesigning the lightning protection systemfor the ARES 1 - scheduled to replace the aging Shuttle fleet in 3 years. The work under the MDA SBIR is directly applicableto this project as well.

The 3 types of system failures triggered by electrical surges are:1. Immediate - the system dies.2. Recoverable - takes a while to get back "on-line."3. Latent - everything seems ok but the system dies later on.

Artist Concept Drawing

MDA SBIR Phase II Subcontractor2005 Award for Research

Slide 10


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Stratospheric Electrical Environments Applicable To Photovoltaic Arrays On HAA Platforms

Slide 11

PHASE II: Down select a specific design for further development to the point of a testable prototype. This could encompass one or more of the lines of

defense described above. Provide subscale prototypes for radiation testing in a simulated space radiation environment. The objective of this program is

to characterize the upper atmosphere electrical environment so that the effects of this environment on high altitude airships (HAA) and other

platforms intending to operate in this environment can be determined and protection methods developed.

MDA – STTR Phase II Current Research


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MDA – STTR Phase II Current(continued)

• Research includes identification and categorizations of transient luminous events (TLEs), such as Red Sprites, Blue Jets, and their associated electrical properties in the region above active thunderstorms, as well as the fair-weather ambient. The induced and directly conducted currents that may be experienced by a near space platforms' PV arrays, will also be defined.

• The approach is to fill gaps in present knowledge with a combination of high altitude electric field measurements; laboratory experiments to examine electrical streamers, leaders, and spark or arc characteristics at reduced pressures equivalent to a 40,000 - 70,000 ft altitude range. Numerical modeling development will be to compute field enhancements and discharge currents at this high altitude regime.

Slide 12


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Why is electrical discharge of concern for near space platform development?Systems and subsystems behave differently when subjected to electrical discharges.

Summary

Dr. Pedro Medelius Associate PM, Chief Scientist SBIR Phase IIASRC Aerospace Corporation M/S ASRC-19 Kennedy Space Center, FL 32899 (321) 867-6335 office (321) 432-7036 cell phone (321) 867-7534 fax

Dr. Cindi Schmitt Chief Scientist, Defense Programs ASRC Aerospace Corporation 985 Space Center Dr., Suite 220 Colorado Springs, CO 80915 (719) 596-9636 office (719) 271-0409 cell phone

Slide 13

Through a Phase I and Phase II MDA SBIR, Lightning Technologies and ASRCAerospace are pursuing research concurrent to platform and vehicle development.We are using NASA and other ground-breaking research into the near spaceelectrical regime to characterize and classify electrical events, and how theseimpact operations in many ways. The three failure scenarios under investigationaffect various systems and components in many ways, and are hard to predictaccordingly.

For further questions:


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References

1. Eberle, M., Marcordes, R., Jaeger, D., Perala, R., Plumer, A., Schwartz, H., Lightning Protection Design Methodology for a Very Large Non-rigid Airship. Int'l Conference on Lightning and Static Electricity Conf., Paper 2001-01-2931, Society of Automotive Engineers, Inc., 2001.

2. NASA. Research Helps Highlight Lightening Safety Awareness Week, http://www.nasa.gov/centers/goddard/news/topstory/2003/061lightning.html

3. NASA. Satellites See Lightning Strikes in Ozone's Origins, http://www.sciencedaily.com/releases/2003/07/030716091100.htm

4. Plumer, J.A. System Functional Upset testing of Aircraft Electrical and Avionic Systems: How to Approach the Planning and Conduct of the Tests. Unpublished White Paper.

5. Plumer, J.A., Perala, R.A., Jaeger, D. Lightning and Electrostatic Charge Effects and Protection Design Approaches for Large Transport Airships. 2003.

6. University of Alaska. Red Sprites and Blue Jets. http://elf.gi.alaska.edu

7. Williams, E. Sprites, Elves, and Glow Discharge Tubes. Physics Today, Nov. 2001.

Slide 14


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BACK UP SLIDES


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The Hindenberg at Lakehurst 1936

804 ft long, 135 ft. dia.200k m3 or 7M ft3 gasMooring ~ 165 ft. high

Backup Slide 1Large airship size

Slide B-1


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Backup Slide 3

Slide B-2

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