ASRC Aerospace
Electrical Discharges in the Upper
Atmosphere and Its Effects on
Near Space Vehicles
Cindi Schmitt, Ph.D.
ASRC Aerospace Corporation
26 April 2007
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Contents
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
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide 1
ASRC Aerospace
Ground Lightning Strike Mitigation
Not the same when it's flying…
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”.
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide 2
Atmospheric Electrical Discharges
ASRC Aerospace
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.
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
"…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
http://gpsinformation.us/humor/Lightening.html
Al Nippon Airliner, Osaka, Japan 2005
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide 3
Examples of Strikes and Vulnerability Aspects
ASRC Aerospace
STS-55
Florida 2005
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Multiple strikes from one
discharge. Whether you
can see them or not…
Slide 4
ASRC Aerospace
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).
Why is electrical discharge a concern for vehicles within our atmosphere?
Answer: Systems and subsystems behave differently when subjected to electrical discharges.
There are 3 types of system failures triggered by electrical surges:
Immediate
Recoverable
Latent
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide 5
Sprites, Elves
ASRC Aerospace
massive, weak
luminous flashes
and Jets
Tendrils extend
down to 30 kms,
Body of the sprite
is 60 ~ 80 km.
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide 6
Video
ASRC Aerospace
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide 7
Lightning Discharge Energy
ASRC Aerospace
Some sprites, referred to as C-Sprites,
are vertically-oriented columns 200 m
wide and 10 km long.
JUNE 20, 2006
NASA Image
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)
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide 8
ASRC Aerospace
Lightning and EM Hazards Protection Designs:
Previous Research Provides Scientific
Basis for Further Study
Glasair III LP
Prototype
FAA FAR23 Reqmts.
Direct-effects testing at LTI's laboratory.
Funded under a NASA Langley SBIR award.
http://www.lightningtech.com/intro.html
CargoLifter CL-160 Lightning and Electromagnetic
Effects (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.
MDA SBIR Phase II Prime
2005 Award for Research
CL-180 1/25 model
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide 9
ASRC Aerospace
Lightning and EM Hazards Protection Designs:
ASRC Aerospace and NASA
ASRC Aerospace is the NASA Kennedy
Space Center Prime Contractor and
Consultant for lightning mitigation.
MDA SBIR Phase II Subcontractor
2005 Award for Research
Currently, ASRC Aerospace personnel are
designing the lightning protection system
for the ARES 1 - scheduled to replace the
aging Shuttle fleet in 3 years.
The work under the MDA SBIR
is directly applicable
to this project as well.
Artist Concept Drawing
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.
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide 10
ASRC Aerospace
Stratospheric Electrical Environments Applicable
To Photovoltaic Arrays On HAA Platforms
MDA – STTR Phase II Current Research
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.
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide 11
ASRC Aerospace
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.
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide 12
Summary
ASRC Aerospace
Why is electrical discharge of concern for near space platform development?
Systems and subsystems behave differently when subjected to electrical discharges.
Through a Phase I and Phase II MDA SBIR, Lightning Technologies and ASRC
Aerospace are pursuing research concurrent to platform and vehicle development.
We are using NASA and other ground-breaking research into the near space
electrical regime to characterize and classify electrical events, and how these
impact operations in many ways. The three failure scenarios under investigation
affect various systems and components in many ways, and are hard to predict
accordingly.
For further questions:
Dr. Pedro Medelius Associate PM,
Chief Scientist SBIR Phase II
ASRC 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
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide 13
References
ASRC Aerospace
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.
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide 14
ASRC Aerospace
BACK UP SLIDES
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Backup Slide 1
ASRC Aerospace
Large airship size
804 ft long, 135 ft. dia.
200k m3 or 7M ft3 gas
Mooring ~ 165 ft. high
The Hindenberg at Lakehurst 1936
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide B-1
Backup Slide 3
ASRC Aerospace
Schmitt_UpperAtmosphericElectricalDischarges_NearSpace_26Apr07.ppt
Slide B-2