Introduction to Parachute Systems

1
Introduction to Parachute Systems
2
Components of a Parachute System
Canopy the major drag producing member of the
parachute
Vent very upper region of the canopy, open to
airflow
Suspension Lines load bearing members extending
from the canopy to the payload
Radials load bearing member running from the
suspension lines at the skirt to the vent lines
Gore section of a parachute canopy between two
radials
Behr, V. and Potvin, J., Parachute Definitions,
Nomenclature and Types, H.G. Heinrich Parachute
Systems Short Course, 15-19 May 2006.
3
Components of a Parachute System
Pilot Parachute a small parachute which is
attached to a deployment bag or the vent of a
larger parachute and is used to provide the force
required to deploy a larger parachute.
Mars Pathfinder Drop Test
Drogue Parachute a parachute which is attached
to the payload and is used to provide
stabilization or initial deceleration or both.
Usually implies a larger parachute will be
deployed later in the event sequence. Frequently
used as the pilot parachute for the main
parachute.
canopy
suspension lines
riser
backshell
Riser a line connecting a parachute to its
payload. May utilize a single or multi-point
attachment scheme.
bridle
Bridle a means of providing a multi-point
connection to a deployment bag or a vehicle from
a parachute or riser.
MPF lander
Witkowski, A., Mars Pathfinder Parachute System
Performance, AIAA 99-1701.
4
Components of a Parachute System
Behr, V. and Potvin, J., Parachute Definitions,
Nomenclature and Types, H.G. Heinrich Parachute
Systems Short Course, 15-19 May 2006.
Cruz, J.R., Parachutes for Planetary Entry
Systems, AE8803 / Planetary Entry, Georgia
Institute of Technology, Spring 2007.
Deployment Bag a textile container for a
parachute from which the parachute deploys. Its
main purpose is to effect an organized deployment
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Components of a Parachute System
Mortar a deployment device used to eject a
packed parachute from the payload as one mass to
begin the deployment process. Mortars are the
most common method of parachute deployment for
spacecraft planetary entry.
Example Mortar Assembly for the Apollo Drogue
Chute
Knacke, T.W., Parachute Recovery Systems Design
Manual, Para Publishing, 1992.
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Typical Parachute Deployment Sequence
Example from Mars Pathfinder
Cruz, J.R., Parachutes for Planetary Entry
Systems, AE8803 / Planetary Entry, Georgia
Institute of Technology, Spring 2007.
Knacke, T.W., Parachute Recovery Systems Design
Manual, Para Publishing, 1992.
7
Common Type of Parachutes Their Uses
Disk-Gap-Band (DGB)
Ringsail
Ribbon
Example spacecraft uses Viking Landers
Mars Pathfinder Mars Exploration Rovers
Mars Phoenix Huygens
Example spacecraft uses Pioneer Venus
Galileo Mercury drogue chutes Gemini drogue
chutes Apollo CM drogue chutes Space
Shuttle SRB chutes
Example spacecraft uses Mercury main chutes
Gemini main chutes Apollo CM main chutes
Image from Mercury program
Image from Galileo wind tunnel test
Image from MER wind tunnel test
Cruz, J.R., Parachutes for Planetary Entry
Systems, AE8803 / Planetary Entry, Georgia
Institute of Technology, Spring 2007.
http//solarsystem.nasa.gov/multimedia/gallery/ Ga
lileo_WindTest.jpg
http// history.nasa.gov/SP-4001/images/fig18.jpg
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Successful Parachute Deployment
Here are two videos that demonstrate successful
parachute in a spacecraft related context

1. Successful drop test from NASA Supersonic
   Planetary Entry Decelerator Program, SPED-1
   (well see some unsuccessful tests from this
   program a little later) (LV-2007-00059)
2. Space Shuttle Solid Rocket Booster (SRB)
   parachute deployment

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Potential Failures (a partial list)
There are many things that can lead to a
parachute system failure. To help you gain a feel
for the types of failure that may occur, lets
look at the following potential failure modes

• Mortar doesnt fire
• Aerodynamic loads exceed design
• Suspension lines become twisted or tangled
• Recontact with reentry and/or parachute hardware
• Dumping the canopy
• Asynchronous inflation of parachute clusters
• Squidding
• Wake recontact
• And many more

Example Genesis Earth entry
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Genesis Failure
When the Genesis spacecraft returned to Earth on
September 8, 2004, the parachutes failed to
deploy. The spacecraft plunged into the Utah
desert at 200 mph and broke apart. The
redundant sets of switches controlling parachute
deployment failed to respond to reentry
deceleration because both sets were installed
backwards as specified in the Lockheed-Martin
design.
http//www.youtube.com/watch?ve875O0hSces
Text and images from the Design Fundamentals
Lecture by L. Guerra
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Potential Failures (a partial list)
There are many things that can lead to a
parachute system failure. To help you gain a feel
for the types of failure that may occur, lets
look at the following potential failure modes

• Mortar doesnt fire
• Aerodynamic loads exceed design
• Suspension lines become twisted or tangled
• Recontact with reentry and/or parachute hardware
• Dumping the canopy
• Asynchronous inflation of parachute clusters
• Squidding
• Wake recontact
• And many more

Example Drop test. After 1.07 seconds of
operation, a large tear appeared in the cloth
near the canopy apex. This tear was followed by
two additional tears shortly thereafter. As a
result of the damage to the disk area of the
canopy, the parachute performance was
significantly reduced however, the parachute
remained operationally intact throughout the
flight test and the instrumented payload was
recovered undamaged. (LV-2007-00064)
12
Potential Failures (a partial list)
There are many things that can lead to a
parachute system failure. To help you gain a feel
for the types of failure that may occur, lets
look at the following potential failure modes

• Mortar doesnt fire
• Aerodynamic loads exceed design
• Suspension lines become twisted or tangled
• Recontact with reentry and/or parachute hardware
• Dumping the canopy
• Asynchronous inflation of parachute clusters
• Squidding
• Wake recontact
• And many more

Example Drop test. Parachute suspension lines
get twisted because the partially inflated canopy
could not restrict the twisting to the attachment
bridle and risers. (LV-2007-00052)
13
Potential Failures (a partial list)
There are many things that can lead to a
parachute system failure. To help you gain a feel
for the types of failure that may occur, lets
look at the following potential failure modes

• Mortar doesnt fire
• Aerodynamic loads exceed design
• Suspension lines become twisted or tangled
• Recontact with reentry and/or parachute hardware
• Dumping the canopy
• Asynchronous inflation of parachute clusters
• Squidding
• Wake recontact
• And many more

Example a. Drop test. One gore of the test
parachute was damaged when the deployment bag
with mortar lid passed through it from behind
approximately 2 seconds after deployment was
initiated. (LV-2007-00061) b. Apollo 15
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Apollo 15 Main Parachute System Failure
All three main parachutes deployed without
incident at an altitude of 10,000 ft One of the
three parachutes deflated while the Apollo 15
capsule was obscured by clouds between 7,000 ft
and 6,000 ft According to the Apollo 15 Main
Parachute Failure Anomaly Report No. 1
(NASA-TM-X-6835)
The most probably cause of the anomaly was the
burning of raw fuel (monomethyl hydrazine) being
expelled during the latter portion of the
depletion firing and this resulted in exceeding
the parachute-riser and suspension-line
temperature limits.
http//www.hq.nasa.gov/office/pao/History/alsj/a15
/ap15-S71-42217HR.jpg
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Potential Failures (a partial list)
There are many things that can lead to a
parachute system failure. To help you gain a feel
for the types of failure that may occur, lets
look at the following potential failure modes

• Mortar doesnt fire
• Aerodynamic loads exceed design
• Suspension lines become twisted or tangled
• Recontact with reentry and/or parachute hardware
• Dumping the canopy
• Asynchronous inflation of parachute clusters
• Squidding
• Wake recontact
• And many more

16
Example of Wake Recontact
Behr, V. and Potvin, J., Parachute Definitions,
Nomenclature and Types, H.G. Heinrich Parachute
Systems Short Course, 15-19 May 2006.