X-43A Flights 2 and 3 Overview

1
X-43A Flights 2 and 3 Overview

• Luat T. NguyenNASA Langley Research
  CenterAerospace Control and Guidance Systems
  Committee MeetingSalt Lake City, UtahMarch 3,
  2005

2
Background
Air-Breathing Launch Systems Are More Efficient
Air-Breathing Systems Possess Significantly
Higher Propulsive Efficiency
Hydrogen Fuel
Hydrocarbon Fuels
Turbojets
Rocket
Rocket Based Combined Cycle
Specific Impulse
Turbine Based Combined Cycle
Ramjets
Scramjets
Turbojets
Ramjets
Scramjets
Rockets
0
10
20
MACH NUMBER
3
Goals/Objectives ofHyper-X Program
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
_at_ Mach 7 and one Mach 10 - Methods verification -
Scaling confirmation Primary Metric Accelerate
Comparison of Ground Flight Data

• TECHNOLOGY
• OBJECTIVES
• - Vehicle design risk reduction
• - Flight validation of design methods
• Design method enhancement
• Hyper-X Phase 2 and beyond

Wind Tunnel-to- Wind Tunnel Comparison
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X-43 Vehicle Geometry
148"
60"
Length 12'4" (3.7 meters) Width 5'0" (1.5
meters) Height 2'2" (0.6 meters) Weight 3000
lb max
19"
26"
30"
144"
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Approach and Methodology
X-43 Vehicle 1
Rudder
H2O
Fads PPTs
Controller
N2
Actuator
Battery
FMU
H2
SiH4
Wing
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Approach and Methodology
Hyper-X Research Vehicle Key Mission Events
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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
Launch Vehicle
Stage Separation
Research Vehicle

• 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

• 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

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RTF AerodynamicDatabase Enhancement
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X-43A Flight 1 Profile vs. Pegasus
2000
1600
q psf
1200
6/01 Mishap
800
400
0
0
1
2
3
4
5
6
7
8
9
Mach
15
Booster Modification

• Approximately 3,345 lbs of propellant removed

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Propellant Off-Load
Machining Completed
Halfway through Machining
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X-43A Flight Profiles vs. Pegasus
2000
1600
q psf
1200
6/01 Mishap
800
400
0
0
1
2
3
4
5
6
7
8
9
Mach
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Fin Actuation System Upgrade
Electronic Control Unit (ECU)
Actuator

• 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

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Stage Separation Aerodynamics

• 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

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Scramjet Unstart PreventionDurascram

• 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

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Flight Simulations
Boost
Separation
Research Flight

• NRTSim (Orbital)
• Full Stack sim up to separation
• Pegasus heritage
• LV analysis, autopilot design, trajectory analysis

• SepSim (Langley)
• 66 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

Primary
Drop-to-Splash (Dryden)

• Full mission simulation
• NRTSim StepSim RVSim

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

• LVSim-D (Dryden)
• Independent LV sim
• Dryden sim environment
• Independent LV analysis

• Post 2 Sep (Langley)
• 66 DOF sep simulation
• Built on POST2 code
• Independent Sep analysis

Back-Up
End-to-End Sim (Langley)

• Full mission simulation
• NRTSim SepSim RVSim

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

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X-43A Flight 2March 27, 2004
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hyper-x_second_flight .avi
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Flight Objectives MetHigh Quality Vehicle and
Engine Data Obtained Provides Basis for
Extensive Analysis and Research
Thrust predicted to 3
Mach 7 Flight
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Mach 7 Thermal ResultsComparison with Flight Data
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X-43 Free Flight
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Flight 3 / Flight 2 Boost Comparison
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Flight 3 Hardware Configuration
Fillet Assembly - Localized Reinforcement -
Revised Attachment Method - Upgraded Pegasus
TPS - Additional structural composite plies
Wing Assembly - Standard Pegasus - Upgraded LE
TPS - Additional themocouples on the right side
FAS - Dual Motors - Gear train -
Electronics/Batteries - Through-bolted actuator
mount
Bulkhead Mounted Avionics - HXLV Specific
Ballast Assembly - Adjusted for Mach 10 trajectory
NOZZLE - Upgraded TPS
Orion 50S Rocket Motor - Upgraded Pegasus TPS -
No propellant offload
X-43 - Upgraded LE TPS
AFT Skirt Assembly - Aluminum - Upgraded TPS on
Fins LE - Standard Pegasus Fins
Ballast/Avionics Module - Aluminum
Hyper-X Adapter - Strengthened panels, GN2 mod
- Aluminum
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X-43A Mission DetailsFlight 3 versus Flight 2
MACH 9.6
(3 sec)
NONE
110,000 ft
-0.5gs
(3 sec)
2.5gs
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X-43A/Booster Separationat M9.7, h109k feet
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X-43A Flight 3 Data
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X-43A Demonstrated Propulsive Efficiency Required
for Future Launch SystemsSafe, Flexible,
Affordable
Airframe Integrated
Turbojets
X-43 scaled
I
sp
Ramjets
Scramjets
Rockets
0
10
20
MACH NUMBER
33
X-43 2004 Flight Summary

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