HLV Crew Abort Assessment - SpaceRefimages.spaceref.com/news/2009/hlv.abort.pdf · 2012. 12. 26. · HLV Crew Abort Assessment July 21, 2009 Doug Whitehead / NASA JSC EG5 [email protected]

Pre-decisional. For Internal use only. 1

HLV Crew Abort Assessment

July 21, 2009Doug Whitehead / NASA JSC EG5

[email protected]

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mailto:[email protected]

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Objective

• Objective

• Review HLV Abort Assessment Team activities

• Abort separation

• Thermal effects of LAS motor on the ET

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Agenda

• Team Charter

• Team Members

• Technical Approach

• Issues Addressed

• Technical Results

• Other Technical Comments

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Team Charter

• Objective

• Develop and analyze abort trajectories for a Crewed HLV. Define realistic environments, define the aerodynamics, and define the abort modes from Liftoff to MECO.

• Goal

• Provide preliminary abort summary and potential abort modes. Define any mandatory changes to Orion or the LAS by July 21.

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Name Org Tech Area Office Email

Doug Whitehead NASA JSC Team Lead 281.483.4699 [email protected]

Doug Pesek Boeing Houston Trajectory 281.244.4074 [email protected]

Justin Kerr NASA JSC Orbiter Rep 281.244.5071 [email protected]

Tri Nguyen NASA JSC Engineering Rep 281.483.0468 [email protected]

Phil Stuart NASA JSC Aerodynamics 281.483.6106 [email protected]

Ed Gonzalez NASA JSC Mission Ops Rep 281.483.1927 [email protected]

Steve Scotti NASA LaRC Aerodynamics 757.864.5431 [email protected]

Bret Picka USA Houston USA Rep 281.282.2859 [email protected]

Ray Gomez NASA JSC Aerodynamics 281.483.6108 [email protected]

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Technical Approach

• Identify Orion/HLV abort modes

• Compared to Orion/Ares

• Define critical HLV abort modes that cannot be implemented as they are on Ares

• Evaluate critical HLV abort modes

• Make recommendations for Orion and/or HLV changes to improve abort approach

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Orion/HLV Abort Modes

Mode Ares HLV

One (1) LAS abort on pad thru LAS jettisonLAS abort on pad through first ATO capability (~160 sec) [Performance based criteria]

Two (2) Untargeted Abort Splashdown (Mode 2 UAS) [No SM ∆V] Same

Three (3) Retro Targeted Abort Landing (Mode 3 RTAL) [SM ∆V] Same

Three (3) Targeted Abort Landing (Mode 3 TAL) [SM ∆V] Same

Four (4) Abort to Orbit (Mode 4 ATO) [SM ∆V] Same

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Issues Addressed

• On-pad abort thermal effects on ET

• Abort at Mach 1.25

• For this quick study the team assumed that this covers Max q and Max drag case

• Abort at Mach 2.0

• ET bow shock interaction with Orion

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At Mach 2.0, the ET bow shock impacts the Orion CM, producing a negative pitching moment

Mach 2.0 Pressure Distribution

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On Pad Abort Thermal Impacts

to ET

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Pre-decisional. For Internal use only.

Evaluation of Effects of Thermal Loading on the HLV External Tank for Orion Abort

byVince Cuda ATK Space

Stephen ScottiNASA Langley Research Center

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Overview•Issue: During abort, and in particular pad abort, provide an assessment of the plume heating on the ET

• Approach

– Groundrule: Provide short turnaround estimate without impacting Orion team

– Evaluate existing LAM data to understand physics and to bound loads

– Quantify ET thermal response to bounding heat load

LAS Motor Test Firing ST-1

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LAS Motor Plume – 1Flowfield Characteristics

* Ref: MSFC memo ER43(06-015) “ER43 Memorandum for Record: Results and Insight Gained via ER43’s Analysis of the CLV’s LAS for the Smart Buyer Team Study.”

• LAS Motor Plume is very collimated at low Mach and plume expands later in the trajectory

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LAS Motor Plume – 2Surface Heating Characteristics on Orion 604

* Ref: MSFC memo ER43(07-008) “Summary of results from computation fluid dynamics analysis of 25° and 30° canted abort motor nozzles for Lockheed’s 604q_mod6 launch abort system.”

• LAS Motor Plume heating increases as plume expands to engulf structure

• Except for localized heating from shock-shock interactions and direct impingement

• Plume heating, CFD predicts majority of surface heating is below 100 Btu/ft2-sec

Mach 2.0 Mach 2.8 Mach 3.5

Max. Surface Heating: 10 Btu/ft2-sec 50 Btu/ft2-sec 150 Btu/ft2-sec

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Orion/HLV Geometry with “Collimated Plumes”

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Thermal Loads

• Detailed flowfield and heating predictions are require for accurate evaluation of HLV ET heat flux

• The highly collimated jet at pad abort conditions is expected to bypass the ET surface (see prior figure)

• Heating quickly drops off as the gas expands

• For initial evaluation of heating on the ET, a surface heating of 150 Btu/ft2-sec from Orion CFD chosen to bound heating effects

LAS Heating Profile on OrionMach 3.5

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Plume Exposure Time

• The LAS Motor burn time is about 3 seconds

• In three seconds the motor has traveled 1448 feet (10G Pad abort assumed)

• The highly collimated jet will yield an exposure footprint of a few feet

• Upon examination of the abort trajectory, the expected exposure time for any surface is estimated to be less than 1 second.

LAS

Mot

or T

hrus

t

Motor Burn Time (seconds)

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Thermal Analysis

•Analysis Approach

• Determine the duration of the thermal pulse

• Determine the thermal loads applied to the ET

• Estimate the ablation rate of the NCFI 24-124 insulation

• Determine the thermal buildup of the Aluminum 2195 structure of LOX tank.

External Tank Layup

NCFI 24-124 insulation

Aluminum 2195

Heat Load

Adiabatic wall boundary

1.0”

0.2”

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External Tank NCFI 24-124 Ablation Rate

•How long does the insulation protect the substructure?

• The ablation rates were extracted from the “External Tank ALWT Thermal Databook”* and applied to the 1” thick NCFI 24-124 foam adjacent to the ET Oxygen tank.

• The ablation rate for a 150 Btu/ft2-sec heating rate yields about 1.5 seconds of protection.

* Ref: “EXTERNAL TANK ALWT THERMAL DATA BOOK”, 80900200102, REVISION F, NOVEMBER, 1999

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Aluminum 2195 Thermal Buildup

•Thermal Analysis• A 1-Dimensional transient finite

difference thermal analysis was performed on a 0.2” thick Aluminum 2195 structure with no insulating foam assumed.

• The initial condition assumed that the wall was at the LOX boil-off temperature and that the back wall was adiabatic (i.e., no credit for LOX on backwall).

• A conservative three second load was applied to the wall.

• Results showed that the final wall temperature was about 356 F.

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Conclusions

•The LAS motor total burn time is less than 3 seconds and the expected exposure time for the External Tank is estimated to be less than one second.

•The insulating foam should provide about 1.5 second of protection which exceeds the expected exposure time of the exhaust jet to the external tank wall.

•Even if the foam provided no protection, the Aluminum substructure would experience a thermal buildup near its thermal design limit of 350 F.

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Mach 1.25 and2.0 Abort Separation

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Side-Mount Heavy-Lift / LAV Separation Analysis

Dr. Lisa LingNASA JSC

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Objectives• Concern: In a launch abort, adverse pitching

moment induced by shock impingement on the Launch Abort Vehicle (LAV) may lead to re-contact between the LAV and the external tank (ET) of the side-mount heavy-lift launch (SMHL) vehicle.

• Objective: Perform 6-DOF simulation to determine separation of the LAV from the launch vehicle and its pitching motion following abort initiation at:

• Mach = 1.25

• Mach = 2.0

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Approach• Analysis tool: Simulation for Prediction of Entry Article

Demise (SPEAD)

• Models implemented:

• LAV mass properties

• Aerodynamics

• LAV aero

• Abort motor thrust increment aero

• Separation dynamics increment aero

• Propulsion

• Abort motor 4-nozzle model

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CFD Analysis at Mach 2

Mach 2, α = -2° plume off solutions

Source: Email from Ray Gomez, Subject: SMSDLV AbortAerodynamics Data, July 9, 2009

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CFD Analysis at Mach 1.25

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Post-Abort Separation Distance

Source for CLV/LAV sep dist plots: Raney, Proud, McFarland, Bendle, “D3T2_LASAbort_JBendle_V2_20090202_controller.ppt”, Project Orion

Mach 1 abort Max Q abort

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Angle-of-Attack Profiles

• +α : LAV steers away from LV• LAV clears the nose of ET at ~ 15 m separation distance:

• t = 0.85 sec for M = 1.25• t = 0.38 sec for M = 2

• +α is maintained prior to clearance of LV in separation

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Pitching Moment Profiles

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Aero Pitching Moments at Mach 2

• Cmc.g. = CmLAV + CmΔAM + CmΔsep + Ctransfer

• CmΔsep = CmCFD_sep – CmCFD_LAVonly

• Ctransfer = (CNLAV+Δ dxmrc – CALAV+Δ dzmrc ) / Lref

• CNLAV+Δ = CNLAV + CNΔAM + CNΔsep

• CALAV+Δ = CALAV + CAΔAM + CAΔsep

• dxmrc = xcg - xmrc

• dzmrc = zcg - zmrc

Time (sec) CmLAV CmΔAM CmΔsep CNLAV+Δ CALAV+Δ Ctransfer Cmc.g.

0 -0.02422 -0.00213 -0.00869 0.261709 0.624976 0.069207 0.034178

0.01 -0.0242 -0.00454 -0.01555 0.274214 0.595262 0.071705 0.027412

0.02 -0.02419 -0.00713 -0.01933 0.283919 0.564658 0.07354 0.022886

0.03 -0.02418 -0.00958 -0.02313 0.293327 0.53564 0.075328 0.018442

0.04 -0.02417 -0.01179 -0.02692 0.302214 0.509257 0.077031 0.014145

0.05 -0.02417 -0.01367 -0.03071 0.310352 0.486676 0.078612 0.010063

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Conclusions

• Adverse aero pitching moment on LAV at abort initiation does not cause LAV to veer towards the ET for re-contact during separation.

• Favorable factors include:

• Location of c.g.

• Offset in abort motor thrust direction from centerline

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Other Technical Comments

• Pad Abort

• Pad abort trajectories should be similar to Orion/Ares

• No need to “steer away” from the ET for the initial separation

• Slightly lower initial altitude for HLV

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Other Technical Comments

• ET Plume Impingement

• No overpressure analysis performed

• Mach 1.25 and Mach 2.0 separation

• Initial separation (up to 2 sec.) looks good

• No analysis of post-LAS burnout separation

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Follow On Activities

• Pad Abort

• Analyze ability to reach ocean from a pad abort

• Plume interactions on ET

• More detailed analysis on thermal and pressure effects

• Separation clearances

• More work needed to look at separation after 2 sec. and HLV stack viability post separation

• LAS jettison time

• Look at impacts to crew escape

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Conclusions

• Looked at two issues related to HLV / Orion aborts

• No issue with LAS plume thermal environments

• No issue with initial separation distance for Mach 1.25 and 2.0 cases

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Recommendations

• No mandatory changes identified for Orion and LAS

• Keep team working on issues identified

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Backup Slides

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Coordinate Systems

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+XSPEAD

+XCLV

+XLAV

-ZCLV

+YCLV

+ZCLV

-YCLV

-YSPEAD

+ZSPEAD

+YSPEAD

-ZSPEAD

13.3°

CLV to LAV frametransformation matrix

LAV to SPEAD body frametransformation matrix

LAS nose out of pageφ

Source: “Orion Vehicle Simulation Data Book”, CEV-MA-08-046.pdf, Jan 8, 2008

LV(not to scale)

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LAV Mass Properties

• LAV loaded mass = 37404.4 lbm• LAV loaded c.g. = (653.5, 0.7, -2.6) inches in CLV

frame• LAV loaded MOI and POI about c.g. in CLV frame

• Ixx = 21052 slug-ft2 Ixy = 249 slug-ft2

• Iyy = 212639 slug-ft2 Iyz = -251 slug-ft2

• Izz = 211499 slug-ft2 Ixz = -2587 slug-ft2

• c.g. and inertia tensor were transformed to SPEAD body frame

•


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Abort Motor Characteristics

• 4-nozzle model with 7% scaled down thrust profile• Clock angles from +Z towards +Y axis in LAV frame:

• Nozzle #1: 45°• Nozzle #2: 135°• Nozzle #3: 225°• Nozzle #4: 315°

• Cant angle = 25°• Nozzle exit area = 320.47 in2

• Thrust offset angle = 0.7° (can be 0.6° – 1.7°) produced by varying nozzle throat areas, thus varying nozzle thrust magnitude which is modeled by thrust scale factors:

• Nozzle #1 scale factor: 0.96294562722• Nozzle #2 scale factor: 1.03705437278• Nozzle #3 scale factor: 1.03705437278• Nozzle #4 scale factor: 0.96294562722

• Thrust action point: • x = 422.608” in CLV frame• radius = 56.887” from centerline

• Atmosphere pressure correction made to vacuum thrust

Sources: 1. “Orion Vehicle Simulation Data Book”, CEV-MA-08-046.pdf, Jan 8, 20082. “AM_Thrust Reduction_Cclayton_20080422.xls”, #0000573310 created Jun 6, 2008 in Windchill3. “cev_las_escape_7per_red_70FNominal.d”, from ANTARES in /vobs/cev/sims/Modified_data/las_propulsion in AGDL

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ACM Characteristics

• 8-nozzle model with omnidirectional vacuum thrust of:• Tvac = 7000 lbf 0 – 7 sec• Tvac = 2500 lbf 7 – 27 sec• Tvac = 0 lbf > 27 sec

• Clock angles from +Z towards +Y axis in LAV frame:• Nozzle #1: 22.5° Nozzle #5: 202.5°• Nozzle #2: 67.5° Nozzle #6: 247.5°• Nozzle #3: 112.5° Nozzle #7: 292.5°• Nozzle #4: 157.5° Nozzle #8: 337.5°

• Nozzle exit area = 9.51 in2• Thrust action point:

• x = 239.968” in CLV frame• radius = 16.055” from centerline

• Atmosphere pressure correction made to vacuum thrust

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LAV Aero Properties• LAV aero: CA, CY, CN, Cl, Cm, Cn at Mach = 1.25, 2

• 2-D interpolation in:

• alpha = -180 to 180 deg

• beta = -90 to 90 deg

• Abort motor aero increment: CA, CY, CN, Cl, Cm, Cn at Mach = 1.25, 2

• 3-D interpolation in:

• alpha = -25 to 25 deg

• beta = 0 to 25 deg

• thrust coefficient = 0, 1.49, 2.58, 3.63, 5.52, 7.47, 10.57, 12.26, 14.36

• Separation aero increment: CA, CY, CN, Cl, Cm, Cn at Mach = 1.25, 2

Sources: 1. “Orion Vehicle Simulation Data Book”, CEV-MA-08-046.pdf, Jan 8, 2008 2. “Orion Aerodynamic Databook”, Ver 0.53, Volume 2, NASA CXP-72167, May 2009

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Launch Vehicle Ascent Trajectory• Altitude, relative velocity, flight path angle, and angle-of-attack

were extracted at Mach = 1.25 and 2 as initial conditions for simulation

• Altitude from SMHL ascent trajectory used to calculate SMHL/LAV separation distance

Source: Email from Mike Tigges, Subject: SMHL ascent trajectory tabulation, Jun 25, 2009

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• ACM firing calculated based on constraint of ±5° angle-of-attack limit

•

• Fired ACM # 1 and 8 if α2 > 5°

• Fired ACM # 4 and 5 if α2 < -5°

• αerror = α2 - αlim

• Mcorrect = Iyy αerror / Δt2

• TACM = Mcorrect / dxACM (where dx = x distance from action point to c.g.)

• TACM is corrected for atmosphere pressure and bounded by the ACM thrust limit

Simplified Attitude Control Model

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Documents

HLV Crew Abort Assessment - SpaceRefimages.spaceref.com/news/2009/hlv.abort.pdf · 2012. 12. 26. · HLV Crew Abort Assessment July 21, 2009 Doug Whitehead / NASA JSC EG5 [email protected]