System design overview of the Mars Pathfinder parachute decelerator subsystem

Fallon, Edward

doi:10.2514/6.1997-1511

Cited by 15 publications

(7 citation statements)

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“…The MPF model parachute was a scale model of the same design as that used for the Mars Pathfinder mission. 2 These designs were chosen to explore the tradeoff between drag and static stability (mainly as determined by the statically stable trim angle of attack). All parachute models were 10.55 percent of the full-scale MER parachute at the time the testing was conducted.…”

Section: Parachutes and Backshell Modelsmentioning

confidence: 99%

“…All parachute models were 10.55 percent of the full-scale MER parachute at the time the testing was conducted. This yielded model parachutes with nominal diameter (D 0 ) and area (S 0 ) of 5.225 ft and 21.44 ft 2 , respectively. The model parachutes' nominal diameter was chosen so as to have the same value as the Viking model parachutes previously tested in the TDT.…”

Section: Parachutes and Backshell Modelsmentioning

confidence: 99%

“…The corresponding total porosities for the full-scale MER parachutes at these conditions are given in table 3. For the total porosity calculations the full-scale MER parachutes were assumed to have a D 0 of 49.5 ft and a composite (i.e., combined disk and band) standard fabric permeability of 108 CFM/ft 2 . These values of the total porosities were used to interpolate the drag and static stability coefficients at the corresponding Mars flight conditions.…”

Section: Mars Flight Conditions and Total Porositymentioning

confidence: 99%

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Wind Tunnel Testing of Various Disk-Gap-Band Parachutes

Cruz

Mineck

Keller

et al. 2003

17th AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar

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*Two Disk-Gap-Band model parachute designs were tested in the NASA Langley Transonic Dynamics Tunnel. The purposes of these tests were to determine the drag and static stability coefficients of these two model parachutes at various subsonic Mach numbers in support of the Mars Exploration Rover mission. The two model parachute designs were designated 1.6 Viking and MPF. These model parachute designs were chosen to investigate the tradeoff between drag and static stability. Each of the parachute designs was tested with models fabricated from MIL-C-7020 Type III or F-111 fabric. The reason for testing model parachutes fabricated with different fabrics was to evaluate the effect of fabric permeability on the drag and static stability coefficients. Several improvements over the Viking-era wind tunnel tests were implemented in the testing procedures and data analyses. Among these improvements were corrections for test fixture drag interference and blockage effects, and use of an improved test fixture for measuring static stability coefficients. The 1.6 Viking model parachutes had drag coefficients from 0.440 to 0.539, while the MPF model parachutes had drag coefficients from 0.363 to 0.428. The 1.6 Viking model parachutes had drag coefficients 18 to 22 percent higher than the MPF model parachute for equivalent fabric materials and test conditions. Model parachutes of the same design tested at the same conditions had drag coefficients approximately 11 to 15 percent higher when manufactured from F-111 fabric as compared to those fabricated from MIL-C-7020 Type III fabric. The lower fabric permeability of the F-111 fabric was the source of this difference. The MPF model parachutes had smaller absolute statically stable trim angles of attack as compared to the 1.6 Viking model parachutes for equivalent fabric materials and test conditions. This was attributed to the MPF model parachutes' larger band height to nominal diameter ratio. For both designs, model parachutes fabricated * Aerospace Engineer; Juan.R.Cruz@nasa.gov † Aerospace Engineer; Raymond.E.Mineck@nasa.gov ‡ Aerospace Engineer; Donald.F.Keller@nasa.gov § Aerospace Engineer; Maria.V.Bobskill@nasa.gov This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States. from F-111 fabric had significantly greater statically stable absolute trim angles of attack at equivalent test conditions as compared to those fabricated from MIL-C-7020 Type III fabric. This reduction in static stability exhibited by model parachutes fabricated from F-111 fabric was attributed to the lower permeability of the F-111 fabric. The drag and static stability coefficient results were interpolated to obtain their values at Mars flight conditions using total porosity as the interpolating parameter. SYMBOLS AND ACRONYMS

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Section: Parachutes and Backshell Modelsmentioning

confidence: 99%

Section: Parachutes and Backshell Modelsmentioning

confidence: 99%

Section: Mars Flight Conditions and Total Porositymentioning

confidence: 99%

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Wind Tunnel Testing of Various Disk-Gap-Band Parachutes

Cruz

Mineck

Keller

et al. 2003

17th AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar

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“…All parachutes used in the drop test series were geometrically similar to that used for the Mars Pathfinder mission 7,8 and thus were classified to be of the MPF type. This parachute type is a modified version of that used by Viking.…”

Section: Test Parachutesmentioning

confidence: 99%

“…5 The parachute used by MER is of the Disk-Gap-Band (DGB) design developed for the Viking mission 6 in 1976 and used on several other missions including Mars Pathfinder 7,8 in 1997. As with prior missions, 9 the MER parachute will be deployed by a mortar.…”

Section: Introductionmentioning

confidence: 99%

Opening Loads Analyses for Various Disk-Gap-Band Parachutes

Cruz

Kandis

Witkowski

2003

17th AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar

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Detailed opening loads data is presented for 18 tests of DGB parachutes of varying geometry with nominal diameters ranging from 43.2 to 50.1 ft. All of the test parachutes were deployed from a mortar. Six of these tests were conducted via drop testing with drop test vehicles weighing approximately 3,000 or 8,000 lb. Twelve tests were conducted in the National Full-Scale Aerodynamics Complex 80-by 120-foot wind tunnel at the NASA Ames Research Center. The purpose of these tests was to structurally qualify the parachute for the Mars Exploration Rover mission.A key requirement of all tests was that peak parachute load had to be reached at full inflation to more closely simulate the load profile encountered during operation at Mars. Peak loads measured during the tests were in the range from 12,889 to 30,027 lb. Of the two test methods, the wind tunnel tests yielded more accurate and repeatable data. Application of an apparent mass model to the opening loads data yielded insights into the nature of these loads. Although the apparent mass model could reconstruct specific tests with reasonable accuracy, the use of this model for predictive analyses was not accurate enough to set test conditions for either the drop or wind tunnel tests. A simpler empirical model was found to be suitable for predicting opening loads for the wind tunnel tests to a satisfactory level of accuracy. However, this simple empirical model is not applicable to the drop tests. SYMBOLS AND ACRONYMS INTRODUCTIONThe structural qualification of the parachute for the Mars Exploration Rover (MER) mission 1,2 was conducted through a combination of full-scale lowaltitude drop tests 3,4 and wind tunnel tests in the National Full-Scale Aerodynamics Complex (NFAC) 80-by 120-foot wind tunnel at the NASA Ames Research Center. 5 The parachute used by MER is of the Disk-Gap-Band (DGB) design developed for the Viking mission 6 in 1976 and used on several other missions including Mars Pathfinder 7,8 in 1997. As with prior missions, 9 the MER parachute will be deployed by a mortar. 10The primary objective of the tests discussed herein was to show compliance with the MER parachute's structural qualification requirement. For the MER mission, this requirement stated that the parachute had to withstand a load 25 percent greater than the calculated maximum opening load at Mars without sustaining damage that would affect parachute performance. The maximum predicted opening load at Mars, including various safety factors and allowances for uncertainties, was calculated to be 19,360 lb. This resulted in a peak load qualification requirement of 24,200 lb for the MER parachute. During Mars operation, parachute inflation occurs under near-infinite mass conditions resulting in an almost constant dynamic pressure during the parachute deployment and inflation. As a consequence the peak opening load during Mars operation occurs when the parachute reaches full inflation. Thus, an additional requirement for the structural qualification tests was that the peak opening load ...

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Entry, Descent and Landing Systems

Lingard¹,

Underwood²

2014

The International Handbook of Space Technology

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System design overview of the Mars Pathfinder parachute decelerator subsystem

Cited by 15 publications

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Wind Tunnel Testing of Various Disk-Gap-Band Parachutes

Wind Tunnel Testing of Various Disk-Gap-Band Parachutes

Opening Loads Analyses for Various Disk-Gap-Band Parachutes

Entry, Descent and Landing Systems

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