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, May 2006.
Space Systems Engineering

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
Space Systems Engineering

4. Components of a Parachute System
Behr, V. and Potvin, J., “Parachute Definitions, Nomenclature and Types,” H.G. Heinrich Parachute Systems Short Course, 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. It’s main purpose is to effect an organized deployment
Space Systems Engineering

5. 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.
Space Systems Engineering

6. 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.
Space Systems Engineering

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:
Mercury main chutes
Gemini main chutes
Apollo CM main chutes
Example spacecraft uses:
Pioneer Venus
Galileo
Mercury drogue chutes
Gemini drogue chutes
Apollo CM drogue chutes
Space Shuttle SRB chutes
Image from Mercury program
Image from MER wind tunnel test
Image from Galileo wind tunnel test
Cruz, J.R., “Parachutes for Planetary Entry Systems,” AE8803 / Planetary Entry, Georgia Institute of Technology, Spring 2007.
history.nasa.gov/SP-4001/images/fig18.jpg
Galileo_WindTest.jpg
Space Systems Engineering

8. Successful Parachute Deployment
Here are two videos that demonstrate successful parachute in a spacecraft related context:
Successful drop test from NASA Supersonic Planetary Entry Decelerator Program, SPED-1 (we’ll see some unsuccessful tests from this program a little later) (LV )
Space Shuttle Solid Rocket Booster (SRB) parachute deployment
Space Systems Engineering

9. 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, let’s look at the following potential failure modes:
Mortar doesn’t 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
Space Systems Engineering

10. Space Systems Engineering
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.
Text and images from the Design Fundamentals Lecture by L. Guerra
Space Systems Engineering

11. 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, let’s look at the following potential failure modes:
Mortar doesn’t 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 )
Space Systems Engineering

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, let’s look at the following potential failure modes:
Mortar doesn’t 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 )
Space Systems Engineering

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, let’s look at the following potential failure modes:
Mortar doesn’t 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 )
b. Apollo 15
Space Systems Engineering

14. 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.”
Space Systems Engineering

15. 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, let’s look at the following potential failure modes:
Mortar doesn’t 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…
Space Systems Engineering

16. Example of Wake Recontact
Behr, V. and Potvin, J., “Parachute Definitions, Nomenclature and Types,” H.G. Heinrich Parachute Systems Short Course, May 2006.
Space Systems Engineering