X-43A Flights 2 and 3 Overview

Luat T. NguyenNASA Langley Research Center

Aerospace Control and Guidance Systems Committee MeetingSalt Lake City, Utah

March 3, 2005

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Air-Breathing Launch Systems Are More EfficientAir-Breathing Systems Possess Significantly Higher Propulsive Efficiency

Turbojets

Scramjets

Ramjets

TurbojetsRamjets

Scramjets

Hydrocarbon Fuels

Hydrogen Fuel

0 10 20MACH NUMBER

SpecificImpulse

RocketRocket Based Combined Cycle

Turbine Based Combined Cycle

Rockets

Background

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Wind Tunnel-to-Wind TunnelComparison

Comparison ofGround

& Flight Data

GOALS: Demonstrate, validate and advance the technology, experimental techniques, and computational methods and tools for design and performance predictions of a hypersonic aircraft powered with an airframe-integrated, scramjet engine.

FLIGHT OBJECTIVES:- Three flights: two @ Mach 7 and one Mach 10- Methods verification- Scaling confirmation Primary Metric: Accelerate

TECHNOLOGYOBJECTIVES:- Vehicle design & risk reduction- Flight validation of design methods- Design method enhancement- Hyper-X Phase 2 and beyond

Goals/Objectives ofHyper-X Program

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148"

30"

19" 26"

144"

60"Length: 12'4" (3.7 meters)Width: 5'0" (1.5 meters)Height:: 2'2" (0.6 meters)Weight: 3000 lb max

X-43 Vehicle Geometry

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X-43 Vehicle 1

Rudder N2 Controller Fads PPTs H2O

Wing H2Battery

FMU Actuator

SiH4

Approach and Methodology

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Hyper-X Research Vehicle Key Mission Events

Approach and Methodology

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B-52 and X-43 Ground Track

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X-43 Mach 7 Flight 1 Trajectory

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First Flight MishapJune 2, 2001

• Nominal flight to launch point

• Drop of booster stack and ignition at 5 seconds after drop nominal

• At ~13 seconds after drop booster departed controlled flight -- right fin broke off, followed, within one second, by left fin and rudder

• Wing broke off at 15 seconds

• Booster data stream lost at 21 seconds

• At 48.5 seconds, FTS initiated by Navy Range Safety Officer while booster was within cleared corridor – no hazard to civilians on ground or air crews

• X-43 data stream lost at 77.5 seconds

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Mishap Description

ORIG_F1.avi

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MIB Findings

• Modeling deficiencies causing over-prediction of autopilot stability margins– Fin Actuation System– Aerodynamics– Mass/Geometry Characteristics

• Over-prediction of fin actuator torque margin– Misprediction of aerodynamic hinge moments

• Other areas for improvement– Validation/Cross Checking/Reviews– Documentation– Workforce

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X-43A RTF Risk ReductionMajor Actions

• Higher fidelity models– Aerodynamics– Actuators– Structures– Autopilot

• Actuator upgrade for greater torque capability

• Lower loads trajectory: booster propellant off-load

• Autopilot trades/optimization

• Independent simulation

• Higher fidelity models

• Additional separation mechanism testing

• Control law refinements for robustness

• Independent simulation

• Higher fidelity models

• Increased AOA for flameout robustness and greater thrust

• Upgraded engine control logic for unstart robustness

• Adapter fluid systems improvements

• Redesign of wing control horns

• Aircraft-in-the-loop timing tests

• Independent simulation

Launch Vehicle Stage Separation Research Vehicle

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RTF AerodynamicDatabase Enhancement

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0

400

800

1200

1600

2000

0 1 2 3 4 5 6 7 8 9

Mach

qpsf 6/01

Mishap

X-43A Flight #1 Profile vs. Pegasus

X-43A Flt. #1

Pegasus

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Booster Modification

• Approximately 3,345 lbs of propellant removed

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Propellant Off-Load

Machining CompletedHalfway through Machining

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0

400

800

1200

1600

2000

0 1 2 3 4 5 6 7 8 9

Mach

qpsf 6/01

Mishap

X-43A Flight Profiles vs. Pegasus

X-43A Flt. #1

X-43A Flt. #2

Pegasus

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Fin Actuation System Upgrade

• Objective: To increase the FAS hinge torque capability from 1850 ft-lbs to 3000+ ft-lbs

• Modifications:– Add second motor in torque summing arrangement– Fabricate new gears to handle higher loads– Change housing material from aluminum to stainless steel– Add two additional batteries– Redesign the power and pre-driver boards in the ECU

Electronic Control Unit (ECU) Actuator

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Ejector Piston Force

Tail Surface Deflection

• Independent time accurate, N-S CFD w/ coupled 3DOF trajectory simulation performed by CFD Research Corp. as part of RTF risk reduction

• Results indicate excellent agreement with NASA SepSim tool and CFD results

• Coupled time accurate simulation predicts clean, controlled separation (no re-contact) trajectory

Stage Separation Aerodynamics

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• Unstart occurs when pressure from combustion causes isolator shock train to propagate forward into the inlet causing massive flow spillage

• Actively controlling fuel flow via isolator pressure feedback (Durascram) to enhance unstart robustness

Scramjet Unstart Prevention:Durascram

Flight Simulations

NRTSim (Orbital)• Full Stack sim up to

separation

• Pegasus heritage

• LV analysis, autopilot design, trajectory analysis

Boost Separation Research Flight

SepSim (Langley)• 6+6 DOF sim of LV & RV

during separation

• Built on MSC/ADAMS code

• Sep analysis, sensitivity studies, collision detection

RVSim (Dryden)• RV flight from post separation

to splash

• Dryden sim environment

• RV analysis, autopilot design, sensitivity studies

• Full mission simulation• NRTSim + StepSim + RVSim

• Manual linking of sims• Validation of individual sim phases/integrated flight

Drop-to-Splash (Dryden)

LVSim-D (Dryden)• Independent LV sim

• Dryden sim environment

• Independent LV analysis

Post 2 Sep (Langley)• 6+6 DOF sep simulation

• Built on POST2 code

• Independent Sep analysis

• Full mission simulation• NRTSim + SepSim + RVSim

• Single user interface, automated linking/integration• Validation of Drop-to-Splash & individual sims

End-to-End Sim (Langley)

Prim

ary

Bac

k-U

p

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X-43A Flight 2March 27, 2004

hyper-x_second_flight .avi

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Flight Objectives Met:High Quality Vehicle and Engine Data Obtained –

Provides Basis for Extensive Analysis and Research

Mach 7 Flight

Thrust predicted to ~3%

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Mach 7 Thermal ResultsComparison with Flight Data

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X-43 Free Flight

Flight 3 / Flight 2 Boost ComparisonAlpha Comparisons

Time, sec

Dynamic Pressure Comparisons

q(lb/ft2)

Time, sec

Mach Comparisons

M

Time, sec

Engine Cowl HeatingParameter Comparisons

HeatingParameter(Btu/ft2sec)

Time, sec

Engine Cowl Heating Parameter Comparisons

AFT Skirt Assembly - Aluminum - Upgraded TPS on Fins LE - Standard Pegasus Fins

Orion 50S Rocket Motor - Upgraded Pegasus TPS - No propellant offload

Ballast/Avionics Module - Aluminum

Bulkhead Mounted Avionics - HXLV Specific

Ballast Assembly- Adjusted for Mach 10 trajectory

X-43 - Upgraded LE TPS

Hyper-X Adapter - Strengthened panels, GN2 mod - Aluminum

Wing Assembly - Standard Pegasus - Upgraded LE TPS - Additional themocouples on the right side

Fillet Assembly - Localized Reinforcement - Revised Attachment Method - Upgraded Pegasus TPS - Additional structural composite plies

FAS - Dual Motors - Gear train - Electronics/Batteries - Through-bolted actuator mount

Flight 3 Hardware Configuration

NOZZLE - Upgraded TPS

X-43A Mission DetailsFlight 3 versus Flight 2

MACH 9.6 (3 sec)

110,000 ft

(3 sec)

NONE

-0.5g’s

2.5g’s

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X-43A/Booster Separationat M=9.7, h=109k feet

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X-43A Flight #3 Data

31

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X-43A Demonstrated Propulsive Efficiency Required for Future Launch Systems

Safe, Flexible, Affordable

Turbojets

Scramjets

Ramjets

0 10 20MACH NUMBER

Isp

Rockets

X-43 scaled

Airframe Integrated

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X-43 2004 Flight Summary

• All program objectives were met– A wealth of high quality flight data substantiates

hypersonic vehicle and engine design tools and scalingmethodologies

+ Stability and control, aerodynamics, boundary layer transition,vehicle structure, TPS, and internal environment performedas predicted

– Proved in flight that an airframe-integrated scramjetworks well - engine performance was very close topreflight predictions

+ X-43 accelerated at Mach 6.83+ X-43 cruised at Mach 9.68, the design condition

– Proved that non-symmetrical high q/high Mach stage separation is very doable, leading the way to future safe staged launch systems

– Paved the way for future systems

• Why were we successful?– Exceptional teamwork across multiple government and industry organizations– Thorough understanding of what we wanted to do and how we were doing it from an

integrated systems perspective– Rigorous processes for design, development, testing, and checking