aedc arc jet test support to mars science lab tps development documents/meeting... · aedc arc jet...

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AEDC ARC JET TEST SUPPORT

TO MARS SCIENCE LAB TPS

DEVELOPMENT

D. Mark Smith Aerospace Testing Alliance (ATA)

Arnold Air Force Base, TN

AIAA HYTASP Technical Committee Meeting

January 9, 2012

Air Force Materiel Command

Arnold Engineering Development Center

Arnold Air Force Base, TN 37389


AEDC ARC JET TEST SUPPORT TO MARS

SCIENCE LAB TPS DEVELOPMENT 9 JANUARY 2012

D. MARK SMITH

AEROSPACE TESTING ALLIANCE

ARNOLD AFB, TN [email protected]


INTRODUCTION

• NASA’s Mars Science Laboratory planetary probe was launched November 25th.

The mission's rover, Curiosity, will land on Mars in August 2012 to study an

intriguing area of Mars. The rover will investigate local environmental conditions

and look for evidence of possible microbial life.

• NASA's Jet Propulsion Laboratory, a division of the California Institute of

Technology in Pasadena, manages the Mars Science Laboratory Project for the

NASA Science Mission Directorate, Washington.

• Mars Science Lab incorporates the largest-ever space vehicle heat shield ever

built for a planetary mission (including Apollo). The aeroshell is designed to

encapsulate and protect Curiosity from intense heat and friction generated during

descent through the Martian atmosphere.

• The heat shield for Mars Science Laboratory's flight will use tiles made of phenolic

impregnated carbon (PICA) ablator. The heat shield and back shell, which together

form the spacecraft’s aeroshell, have a diameter of 4.5 meters (nearly 15 feet).

• MSL heat shield testing was conducted in the AEDC H2 arc tunnel at the request

of NASA Ames Research Center, Moffett Field, CA. AEDC testing complemented

extensive MSL and Orion TPS tests in the NASA IHF/AHF and ARMSEF TP-2 arc

jets.


OUTLINE

• Scope and objectives

• Facility and test article configuration

• Test results

• Photos and videos

All MSL Images courtesy of JPL website

http://marsprogram.jpl.nasa.gov/msl/

MSL „Curiosity‟ heat shield assembly w/

stowed rover in top shroud

Aviation Week H2 CEV TPS test article


http://marsprogram.jpl.nasa.gov/msl/

OVERVIEW

• Program: NASA MSL and CEV/Orion (Joint) • Sponsor: NASA Ames Research Center, Moffett Field, CA • Scope (MSL Tests): 1 validation run, 5 test runs* • Test Conductors: Robin Beck (NASA), Bill Willcockson (L-M) • Primary Data

• Facility operating conditions • Flow total enthalpy, pressure, power

• Flow calibration data • Stagnation heat flux and pressure • Wedge heat flux and pressure • 15- and 20-deg wedge angles

• TPS material response on “pilot” test samples • Digital surveillance videos to monitor ablation phenomenology • IR camera imaging • Radiometer (brightness temperature)

* Conducted as part of the larger 25-run NASA Orion TPS Advanced Development Program testing in H2


OBJECTIVES AND APPROACH

Objectives

• Demonstrate a suitable test point for high-shear materials testing of thermal protection system (TPS) candidates for the NASA Orion/CEV and Mars Science Lab (MSL) space vehicles

• Obtain flow-field calibration data defining the test point(s) selected

• Obtain initial evaluation of TPS thermal-structural response for SLA (Lockheed‟s legacy “Super Lightweight Ablator”) and PICA TPS test samples*

* Aeroheating conditions provided by H2 for thjis test are severe relative to MSL requirements, and provide material response parameters at „worst case‟ ablation conditions

Approach

• Reconfigure the H2 arc heater for maximum enthalpy at low mass flow rate. Maximum enthalpy was needed for the best possible match of shear stress and heat flux with MSL trajectory heating.

• A validation test was completed to explore operation of the H2 arc tunnel with the highest enthalpy possible in the 15 to 20-atm pressure regime using existing facility hardware in short-cathode configuration


DAC2 Qdot vs Local Pressure, Rev.4 Margin Policy

Archive and Predicted Stagnation TP adjusted to 4" Iso-Q FC Surface

0

200

400

600

800

1000

1200

0 10 20 30 40 50 60 70 80 90 100

Surface Pressure (kPa)

Tota

l H

eat

Flu

x (

W/c

m2)

LDR ISS TP2_CEV IHF_CEV IHF171_r4iQ IHFn6_data

IHFn13_data IHFn21_data TP2_Orbiter AHFn7u AHFn12_data AHFn24_data

IHFn8c IHFn8_AA IHFn13c IHFn13_AA IHFn21c Blk2P2

env_LR_skp env_ISS_skp ARMSEF_c Orbiter_5505

CEV Risk

Concern Area #1

#2 #3 #4

CEV/MSL FORWARD HEAT SHIELD TPS RISK AREAS

CEV envelope courtesy of

Raiche, NASA/ARC (2008)

H2 nominal test points from

Smith, AEDC (2008)

#2

#4

MSL

MSL RISK AREA Target Conditions

qdot = 260 W/cm^2

t = 480 Pa

Psurf = 39 kPa


WHY H2?


Current

ARC IHF

Heat F

lux,

W/c

m2

Surface Pressure, kPa

Current

ARC AHF

Reactivated 7”

AHF Nozzle

0

100

200

300

400

500

600

700

800

0 10 20 30 40 50 60 70 80 90 100

JSC

TP2

(1 atm)

Flight envelopes

LDR Ballistic ISS Ballistic LDR Skip ISS Skip

#1

#2

#2 (D, NC)

M=3.4 PCH=30 atm

20-deg wedge

Qdot ~280 w/cm2

Psurf ~100 kPa

T wall ~ 900 Pa

#1 (D, C)

M=4.4 PCH=33 atm

20o wedge

Qdot ~ 60 w/cm2

Psurf ~ 18 kPa

T wall ~ 250 Pa

#3 (ND, NC)

M=3.4 PCH=20 atm

15o wedge

Qdot ~ 240 w/cm2

Psurf ~ 60 kPa

T wall ~ 590 Pa

#4 (ND, NC)

M=3.4 PCH=34 atm

10-deg wedge

Qdot ~220 w/cm2

Psurf ~ 76 kPa

T wall ~ 710 Pa

#4

Possible AEDC H2 Wedge Flow

Test Points for CEV High-Shear Key: D –Demonstrated run condition

ND—Run condition not demonstrated

C—Flow calibration data taken

NC—Calibration data not available

#A (D, C)

M=3.4 PCH=15 atm

15o wedge

Qdot ~ 210 w/cm2

Psurf ~ 45 kPa

T wall ~ 560 Pa

#3

ARC/JSC envelopes fr. Raiche, et al

MSL

MSL RISK AREA Target Conditions

qdot = 260 W/cm^2

t = 480 Pa

Psurf = 39 kPa

#A

OUTLINE



• Test results

• Photos and videos MSL aeroshell backstructure


SUMMARY OF TEST CONDITIONS

SUMMARY: HEAT-H2 ARC HEATER AND FLOW-FIELD CONDITIONS

H2-025-003 (Validation Run)

H2-025-010 to -011 (SLA TPS Ablation Runs)

RUN NO. RUN DATE PCH ARCI ARCV PWR EFF MIX/WA MDOT RUN TIME HOB HoINF* QDOToHW** Po'

H2-025 TYPE (atm) (amp) (Kvolt) (MW) (%) (%) (lb m /s) (sec) (Btu/lb m ) (Btu/lb m ) (Btu/ft2-sec) (atm)

-003 Facility Validation 4/30/07 15.9 3,100 3.72 11.5 65 0.0 2.10 204.0 3500 4,968 2,000 2.0

-010 TPS Ablation (SLA) 8/14/07 16.8 3,073 3.96 12.2 68 0.0 2.12 136.0 3800 4,601 1,900 2.1

-011 TPS Ablation(SLA) 8/16/07 14.8 3,109 3.67 11.4 66 0.0 1.88 126.0 3900 4,969 1,930 1.9

NASA MSL Facility Validation and TPS Testing

*Nominal centerline inferred enthalpy ** Stagnation heat flux on a 0.25"R hemisphere calorimeter ***Average bulk enthalpy for runs -010 to -011.

Additional PICA and SLA samples were

tested for MSL on Runs -012, -013, and -014.


OUTLINE



• Test results

• Photos and videos MSL aeroshell w/ mock heat shield in place


H2 WEDGE FLOW PROPERTIES

DMS 8-17-07

Run Facility PCH Wedge > Mfs Hr Vfs Me Me/Mfs Ue*

H2-025 atm deg Btu/lbm ft/sec Btu/ft2-sec w/cm

2 atm kPa M ft/sec lb/ft2 Pa

-001 H2 23.0 15 3.4 5000 11,920 320 362 0.61 61.8 2.04 0.60 7152 14.2 711

20 3.4 5000 11,920 400 452 0.72 72.8 1.90 0.56 6675 16.6 829

-002 H2 23.0 15 3.4 4200 11,200 280 316 0.61 61.8 2.04 0.60 6720 13.9 696

20 3.4 4200 11,200 340 384 0.72 72.8 1.90 0.56 6272 15.8 788

-003 H2 16.0 15 3.4 4600 11,520 200 226 0.43 43.0 2.04 0.60 6912 9.3 467

20 3.4 4600 11,520 260 294 0.50 50.7 1.90 0.56 6451 11.3 566

-010 H2 16.8 10 3.4 4600 11,520 180 203 0.31 31.6 2.14 0.64 7373 9.0 448

-011 H2 14.8 15 3.4 4800 11,720 210 237 0.40 40.4 2.14 0.60 7032 9.6 478

NASA-MSL H2 Test Points

Qcw Psurf

H2-025 Tests

Gas Wall Shear

Note: Runs -001 and -002 were Orion facility validation runs.

AEDC wedge and stagnation sweep probes

Additional PICA and SLA samples were tested

for MSL on Runs -012, -013, and -014.

Typical Test Points for NASA MSL H2 Arc Jet Tests


PRETEST PHOTOS--PICA

Acreage PICA—0-deg fiber 20-deg fiber—away from the flow 40-deg fiber—away from the flow

RTV-fillled 0.100 gap. Fiber

orientation +/- 10 deg on gap sides RTV-fillled 0.100 gap. Fiber orientation

+/- 20 deg on gap sides


Ref. Beck, et al, “Quick Summary of CEV/MSL PICA Shear Tests at AEDC, NASA QLDR, Jan., 2008.

POSTTEST PHOTOS--PICA

Acreage PICA—0-deg fiber 20-deg fiber—away from the flow 40-deg fiber—away from the flow

RTV-fillled 0.100 gap. Fiber orientation

+/- 10 deg on gap sides RTV-fillled 0.100 gap. Fiber orientation

+/- 20 deg on gap sides

RTV-fillled 0.100 gap. Fiber

orientation +/- 0 deg on gap sides


Ref. Beck, et al, “Quick Summary of CEV/MSL PICA Shear Tests at AEDC, NASA QLDR, Jan., 2008.

RECESSION COMPARISON—PICA VARIANTS

Acreage PICA (Variant AA-46-206N) ___

Surface Densified PICA (Shear 1-Appr-B)

Distance From Front of the Sample (mm)

Su

rfa

ce

Re

ce

ssio

n (

mm

)

20-deg wedge (PICA acreage)

20-deg

wedge

(CEV ADP

Entry I)

20-deg

wedge

(CEV ADP

Entry II)

Average PICA Recession Comparison—Entry I and II


Ref. Beck, et al, “Quick Summary of CEV/MSL PICA Shear Tests at

AEDC, NASA QLDR, Jan., 2008.

PRETEST PHOTOS--SLA

Sample # 4

Flow

Flow

Flow Sample # 5

Sample # 2


ARC-ON PHOTOS--SLA

Sample # 4

Flow

Flow

Flow Sample # 5

Sample # 2


H2 TEST VIDEO (TYPICAL)

H2 Test Video--Typical CEV/MSL Run

Test article indexes in @ t=32 sec


Typical CEV-MLS Test Video (H2-030-005).avi




MSLAnimFull.wmv

POSTTEST PHOTOS--SLA

Sample # 4

Flow

Flow

Flow Sample # 5

Sample # 2


MATERIAL FAILURE SITES--SLA

Sample # 4

Flow

Flow

Sample # 5


CONCLUSIONS

• Relative performance of PICA variants and SLA TPS were evaluated in

H2 high-shear ablation tests and in comparative testing at NASA ARC

and JSC

• FMI’s PICA material (also of interest at the time for CEV applications)

exhibited good high-shear thermal performance for acreage and gap

seals at the test conditions of interest

• The legacy SLA TPS material exhibited inadequate thermostructural

integrity when tested at the maximum-shear conditions anticipated for

MSL planetary entry on the forward heat shield

• Posttest ablative honeycomb site vacancies were observed in both the H2 arc tunnel

at max shear and at NASA AHF/IHF arc jets in testing under moderate-shear

conditions with add-air (mixing air)

• Existing material response models were inadequate to predict material response

with appropriate survivability margins at elevated shear levels

NASA selected PICA as MSL forward heat shield TPS material

SLA-561 V was selected as backshell TPS material for MSL


OUTLINE



• Test results

• Photos and videos


MSL PHOTOS Ref. Link: MSL “Curiosity” images from JPL website:

http://mars.jpl.nasa.gov/msl/multimedia/images/

DHS Spirit = ~8.5 ft.

DHS Apollo = ~13.0 ft.

DHS MSL = ~15.0 ft.

DHS MPCV = ~16.5 ft.

Curiosity rover in “stowed” configuration MSL Mars entry aeroshell

MSL payload arrving at launch pad

Finishing touches on the stowed rover


http://mars.jpl.nasa.gov/msl/multimedia/images/

JPL MSL VIDEO

JPL MSL Animation

THAT’S ALL, FOLKS

Entry/landing sequence concludes @ t=1:30

“Thanks again on behalf of MSL for helping us test and helping us to ascertain that we

really did need to switch heatshield materials.”

Dr. Helen Hwang, MSL TPS Project Manager

NASA Ames Research Center



MSLAnimFull.wmv

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