NASA Technical Reports Server (NTRS) 19980018480: The NASA Hyper-X Program

12 Pages·0.81 MB·English

by  NASA Technical Reports Server (NTRS)

_._ A,,//--/7/_._- 207243
/F91
o 4 y_5_
IAF-97-V.4.07
The NASA Hyper-X Program
D. Freeman, D. Reubush,
C. McClinton, and V. Rausch
NASA Langley Research Center
L. Crawford
NASA Dryden Flight Research Center
48th International Astronautical Congress
October 6-10, 1997/Turin, Italy
Forpermissionto copyorrepublish,contact the International Astronautical Federation,
3-5,RueMario-Nikis,75015Paris,France

The NASA Hyper-X Program
Delma C. Freeman, Jr.,1David E. Reubush, 2Charles R. McClinton, 3Vincent L. Rausch, 4
and J. Larry Crawford 5
Abstract
This paper provides an overview of NASA's Hyper-X Program; a focused hypersonic technology effort designed to
move hypersonic, airbreathing vehicle technology from the laboratory environment to the flight environment. This
paper presents an overview of the flight test program, research objectives, approach, schedule and status. Substan-
tial experimental database and concept validation have been completed. The program is currently concentrating on
the first, Mach 7, vehicle development, verification and validation in preparation for wind-tunnel testing in 1998
and flight testing in 1999_ Parallel to this effort the Mach 5and 10 vehicle designs are being finalized. Detailed
analytical and experimental evaluation of the Mach 7vehicle at the flight conditions is nearing completion, and will
provide adatabase for validation of design methods once flight test data are available.
Introduction among these technologies are airbreathing engines for
hypersonic flight. NASP brought the materials and
The development of reusable launch vehicles holds great design methods for scramjet (supersonic combustion
promise as the key tounlocking the vast potential of ramjet) engines to the point that efficient engines and
space for business exploitation. Only when access to practical vehicles which use them can be developed.
space is assured with asystem which provides routine One of the major requirements to have these technolo-
access with affordable cost will businesses be willing to gies accepted is a flight demonstration. In the spirit of
take the risks and make the investments necessary to real- "Faster, Better, Cheaper" NASA has initiated the
ize this great potential. The current NASA X-33 and X- Hyper-X Program to demonstrate that scramjet engines
34 Programs are steps on the way toenabling the routine, can be designed, constructed, and will operate at the
scheduled access to space. Unfortunately, while agreat high Isp levels necessary for use in access to space vehi-
improvement over current systems, the cost per pound cles as an initial step to this end.
delivered to orbit for currently proposed systems will still
be greater than that needed to exploit space for many The NASA Hyper-X Program employs a low cost
business uses. One of the limiting factors inpotential approach to design, build, and flight test a series of
cost reductions for chemical rockets isthe Isp limit. small, airframe-integrated scramjet powered research
vehicles at Mach numbers of 5, 7, and 10. The research
The use of airbreathing engines holds potential for very vehicles will be dropped from the NASA Dryden B-52,
significant increases inIsp which could result in a sig- rocket boosted to test point by a Pegasus first stage
nificantly lower cost per pound to orbit. The National motor, separated from the booster, and then the scram-
Aero-Space Plane Program (NASP), which was can- jet powered vehicle operated in autonomous flight.
celed in 1995 as unaffordable at that time, was ajoint The Hyper-X Program includes extensive CFD analy-
NASA/U.S. Air Force effort to develop a single-stage- ses and validation, design method verification, and
to-orbit, airbreathing vehicle. However, while the ground testing (to include tests of the actual flight vehi-
NASP was never completed, the NASP program devel- cles for Mach numbers of 5 and 7 inthe Langley 8-
oped asignificant number of technologies which only Foot High Temperature Tunnel). This paper will
await demonstration before they will begin to be describe the Hyper-X Program and will report on the
accepted for use in future aerospace vehicles. Key progress toward construction of the first flight vehicle.
1. Director, Aerospace Transportation Technology Office, NASA Langley Research Center
2. Hyper-X Stage Separation Manager, NASA Langley Research Center
3. Hyper-X Technology Manager, NASA Langley Research Center
4. Hyper-X Program Manager, NASA Langley Research Center
5. Hyper-X Flight Project Manager, NASA Dryden Flight Research Center.
Symbols and Abbreviations M Mach number
AETB Alumina Enhanced Thermal Barrier MDA McDonnell Douglas Aerospace
AIL Aircraft In the Loop NASP National AeroSpace Plane
ALFE Air Launched Hight Experiment NM Nautical Miles
AOA Angle Of Attack PCM Pulse Code Modulated
CST Combined Systems Tests PID Performance Identification
DCM Direct Connect Module psf pounds per square foot
de elevator deflection q dynamic pressure
DFRC Dryden Hight Research Center TPS Thermal Protection System
DFX Dual-Fuel eXperimental TSP Temperature, Strain, and Pressure
EAFB Edwards Air Force Base VAF_ Vandenberg Air Force Base
EMI ElectroMagnetic Interference WTR Western Test Range
FCGNU Flight Control, Guidance, and 8'HTT 8Foot High Temperature Tunnel
Navigation Unit
FMS Force Measurement System
fps feet per second Hypersonic airbreathing propulsion has been studied
by NASA for nearly 60 years. Numerous scramjet
VI'S Hight Termination System tests have been performed in a number of ground
facilities e.g., refs. 1-5. However, these tests have
GASP General Aerodynamic Simulation limitations. For example, allground test facilities
Program have contamination when compared with flight in the
atmosphere. This contamination affects combustion
GVT Ground Vibration Tests (ignition, flameholding and combustion contribution
to engine thrust), boundary layer formation and fuel
HRE Hypersonic Research Engine mixing characteristics. In addition, facility size gen-
erally limits the experiment scale, resulting in sub-
HXLV Hyper-X Launch Vehicle scale or partial simulation of the scramjet flowpath.
For example, no test has been performed on acom-
I-IXRV Hyper-X Research Vehicle plete airframe integrated scramjet. Another limita-
tion is in data measured. Scramjet tests to date focus
HyFlitE Hypersonic Flight Experiment on engine thrust, component efficiencies, and com-
bustion efficiency. Little if any effort is expended,
HySTP Hypersonic Systems Technology for example, on quantification of lift and/or pitching
Program moment contributions from the engine thrust angle or
from the asymmetric nozzles used in this type of
INU Inertial Navigation Unit application. These measurements, and validation of
the prediction of these effects will be important for
Isp Specific Impulse any flight application of scramjet propulsion. Only
through flight tests can these limitations be removed
LaRC Langley Research Center and the promise of scram jets verified.
2
Inthe
United States, scramjet engines have almost operational concept and still demonstrate scramjet pow-
reached flight ontwo occasions. The Hypersonic ered acceleration. In addition, evaluation of operability
Research Engine (I-IRE) project of the 1960's was limits indicated that the scramjet would be operating far
focused on flying an axisyrnmetric scramjet mounted on enough from flameholding and ignition limits so that
the X-15 (fig. 1), but the X-15 project was canceled hydrogen-fueled operation could be achieved. The 12-
before flight of an operating HRE could take place. foot size (with awing span of about 5feet) (fig. 2) was
The NASP andfollow-on HySTP programs of the ultimately selected over a 10foot vehicle because of
1980's and 1990's came close to flying an airframe small performance gains with minimal effect on overall
integrated scramjet. After the demise of NASP and program cost (the increased size did not affect booster
HySTP NASA management, understanding the signifi- selection). The conceptual design for the Hyper-X was
cant potential of airbreathing hypersonic engines for performed between February and May, 1995, by
beth access to space and rapid endoatmospheric flight, McDonnell Douglas Aerospace (MDA) under contract
realized that itwould not be wise to allow the advances to NASA (ref. 6). Shortly thereafter, at the urging of the
made by NASP tobe lost and hypersonic technology NASA Administrator, the Office of Aeronautics and
development enter into another hiatus of 15years like Space Transportation Technology in NASA Headquar-
that at the end ofthe I-IRE program. As aresult, a series ters held an internal agency competition for proposals
of small contracts were issued to examine realistic vehi- which would utilize flight testing to make significant
cles which could be conslructed using the NASP tech- aeronautical advances (ref. 7). Utilizing the results of
nology base, to determine the minimum size flight the studies the NASA Langley Research Center entered
research vehicle (size isa major cost driver), and to the competition with its scramjet flight demonstration
develop aflight test approach todemonstrate the NASP selected as one of the two proposals to be funded (fig.
technology, inparticular, the viability of scramjet 3). To save time after winning the competition NASA
engines in flight. These studies indicated that a 10-12 Langley made use of the Dual-Fuel Airbreathing
foot vehicle could be "smart scaled" from a200-foot Hypersonic Vehicle Design Study (ref. 8) to develop
the preliminary design of the vehicle. This effort was
completed between March and October, 1996 under
contract to MDA. The Hyper-X research vehicle is
essentially photographically scaled from these previous-
lystudied concepts. This allowed utilization of existing
data bases, aswell as rapidly converging to acontrol-
lable flight test vehicle with low trim drag penalty. The
scramjet flowpath, on the other hand, was re-optimized
for engine operability and vehicle acceleration, account-
ing for scale, wall temperature effects, etc. For exam-
ple, the inlet contraction, fuel injector details and com-
bustor length have been modified, rather than simply
photographically scaled. Atthe conclusion of the pre-
liminary design a competition was held for acontractor
Figure 1. X-15 with HRE
Goal: Demonstmta Idvanoed, airframe-Integrated, airbroathlng
hypersonic propulsion system and other key enabling
technologies
vie_:
•Significantly advances the state-of-the-ad
f 12ft. .__
•Acquires crucial data, unavailable Inground tests
•Validates key technologies lind design methods that enable alr-
5ft. breathing aerospace planes for hypersonic cruise and space access
Ao_h :Two-phase, _ prognim
•Phase 1: |lrlrame-lntegnded, dual-mode scramJet
-Four 124oot, uncmwed, expendabie test vehicles
-Flyat Math 5,7,10, 10
•Phase 2builds on Phase I results: • larger-scale, reusable X-plane
(nol afunded program)
-Airlrsme-lntegrated combined-cycle propulsion
-Right envelope expansion from takeoff through hypersonic speeds
Figure 2. Hyper-X Research Vehicle Configuration Figure 3. Hyper-X Program
to develop thefinal design and subsequently fabricate thermal data base development, thermal-structural
the Hyper-X research vehicle. This competition was design, boundary layer analysis and control, flight
won by ateam led by Micro Craft of Tullahoma, Ten- control law development and flight simulation models.
nessee including Boeing -North American of Seal
Beach, California, GASL of Ronkonkoma, New York, The flight test part of the Hyper-X Program focuses
and Accurate Automation of Chattanooga, Tennessee. directly on the advancement of key technology readi-
The team was awarded acontract for Hyper-X design ness levels, elevating them from the laboratory level
and fabrication in March, 1997. At about the same time to the flight environment level required before pro-
Orbital Sciences of Chandler, Arizona was awarded the ceeding with a larger, crewed X-plane or prototype
contract for the Hyper-X launch vehicle which will be a program. In addition, the flight test portion must
modified version of Orbital's Pegasus launch vehicle. advance many flight test techniques.
(See fig. 4for timeline.)
Rather than starting the flight vehicle design on a
clean sheet of paper, the program used the extensive
Prom'am Goals and Aoproach National Aero-Space Plane (NASP) data base, and
follow-on hypersonic mission study programs (ref.
The goal of the Hyper-X Program is to demonstrate 8). Also, to meet budget and schedule, the flight
and validate the technology, the experimental tech- research vehicle is based on existing design data
niques, and computational methods and tools for bases, and off-the-shelf materials and components
design and performance predictions of hypersonic wherever possible. For example, the copper alloy
aircraft with an airframe-integrated, dual-mode engine materials and fabrication methods are similar
scramjet propulsion system. Accomplishing this goal to those used for many experimental wind-tunnel
requires flight demonstration of a hydrogen-fueled, programs, rather than the flight weight actively-
dual-mode scramjet powered, hypersonic aircraft. cooled material systems that will be required for
operational hypersonic aircraft. So in summary, the
The technology portion of the program concentrates Hyper-X program is aimed directly at demonstrating
on three main goals: and flight-validating airframe-integrated scramjet-
1) risk reduction -- i.e., preflight analytical and powered vehicle performance while concurrently
experimental verification of the predicted perfor- continuing the development of design methods and
mance and operability of the Hyper-X flight experimental tools for future vehicle development.
vehicle,
2) flight validation of design predictions, and
3) continued development of the advanced tools Fli2ht Test Program
required to improve scramjet powered vehicle
designs. The flight test portion of the Hyper-X Program con-
This activity includes analytical and numerical meth- sists of four flights. The first, currently scheduled for
ods applied to design the scramjet engine, wind tunnel mid-1999, will be to Mach 7. The second toMach 5
verification of the engine, vehicle aerodynamic and and two subsequent flights to Mach 10 will follow on
an approximately yearly basis (fig. 5). The fLrst
: cv. : C_7
I I
FY 117 II0 90 00 01 02
[_ NASA Flight Domo i ODFA AODFAJAODFAJA DFAJAOOFAJA D A J AO
Selection Te_lm I.lyper-X NAR :
*...'o,,I '.
! I t
! 1 I
1 tGovernment _GGvllmmen_Furnlshtd i i i .1,o
tDeatlin SuReort ti _i ::i i_i i ii _' '._....!._ i!
_It t
NASP -I' i ,
HI"I"_ HlilhTemlurmum Tunn_
HX-LV -- Hyper-X Launch Vehicle
FDCLV-- Hylxw-X_ Veh_
HX-RV -- Hyper-X Research Vehicle
DF -- Dual Fuel Research Vehicle Contract mmv -- Ht_,.x Rmm_mh v_
Figure 4. Timeline leading to Hyper-X Program Figure 5. Hyper-X Program Schedule
4
flight is to Mach 7because that flight will actually be point, the research vehicle will be ejected from the
less difficult than Mach 5. At Mach 7the engine will booster-stack and start the programmed flight test.
be in full scramjet operation and the desired flight Once separated from the booster, the research vehicle
test conditions and Pegasus booster are relatively will establish unpowered conlrolled flight. The
evenly matched. At Mach 5the engine will be in the autonomous flight controller will also determine the
transition from ramjet operation to scramjet operation true flight conditions, which are required tocorrectly
which is a more difficult design problem and the program the fuel system. Following the powered engine
Pegasus booster will most likely require a propellant test and 15seconds of aerodynamic parameter identifi-
off-load to achieve the desired test conditions. The cation maneuvers (refs. 9and 10) the cowl door will be
Mach 10 flights (one cruise flight and one accelera- closed. The vehicle will then fly a controlled decelera-
tion flight) will be last because Mach 10imposes tion trajectory to low subsonic speed. During descent,
much higher loads (heating, etc.) on the vehicle than the vehicle control system will initiate S-turn maneu-
the other flights and the Pegasus booster must vers to dissipate vehicle energy. In the process, short-
approach its performance limits to achieve the duration programmed test inputs will be superimposed
desired test points. It isalso desirable to utilize the onthe control surface motions to aid in the identifica-
results from the Mach 7and 5flights to help opti- tion of aerodynamic parameters. Fully autonomous,
mize the vehicle for these difficult conditions. these vehicles will fly preprogranamed 400-mile routes
inthe Western Test Range (WTR). Air Force Vanden-
All flights will be conducted from NASA Dryden Flight berg, and Navy Point Magu assets will be used for data
Research Center (DFRC) at Edwards, Califomi& The downtinking and tracking. The first flight will be aimed
Hyper-X research vehicle/launch vehicle stack will be due West to avoid disruption of commercial flight corri-
mounted under the wing of the DFRC B-52, carried off dors and any possible damage or injury should the vehi-
the Califomia coast to launch altitude (fig. 6) and cle go out of control. Ifthe first flight isentirely suc-
released. Nominal flight sequence for the Mach 7 flight cessful the Mach 5flight may be aimed down the coast
test isillustrated in figure 7. Following drop from the to achieve a possible landing at Navy facilities on San
B-52 and boost to a predetermined stage separation Nicholas Island (fig. 8).
The desired test condition for the Hyper-X in free
flight is a dynamic pressure of 1000 pounds per
square foot. For the Mach 10tests, launch from the
B-52 will take place at 40,000 feet. For the lower-
speed tests, however, booster launch at lower alti-
tudes will restrain the HXLV from over-accelerating
the Hyper-X. For this same reason, in fact, the boost-
er assembly will also incorporate up to 5tons of bal-
last. For the Mach 5test, the HXLV may even fly
with a reduced propellant load. The research vehicle
will be boosted to approximately 85,000 feet for tests
at Mach 5, 100,000 feet for tests at Mach 7, and
110,000 feet for tests at Mach 10.
Figure 6. Hyper-X Stack Mounted on B-52
/- Pow_Tm S_
Medl7,/ PIO10$e¢$
_,.a, ?
) . %
___ Launchpolnt-_\i/- VAFB_ i
+,.... _._<-..,..<..-_..'+ ,e.',- EAF_B i
% "-- Mission \ _"_-,._ .... J
completion L PI Munu
(Splashl) " :'
o
ol_lc 5wN: -solie -oole_ _...%A.J.J
Figure 7. Hyper-X Nominal Trajectory Figure 8. Hyper-X Range
Vehicle Development (fuel system and internal cavity purge) are contained
in off-the-shelf fiber wound aluminum tanks. Instru-
An industry team led by Micro Craft, Inc., of Tulla- mentation, flight and engine cowl control actuators
homa, Tennessee, has been selected to design and fab- and controllers, and the flight control computer are
ricate the hypersonic vehicles. Micro Craft will build all either off-the-shelf or derivatives of existing units.
the vehicles and provide overall program manage- A high pressure water system is included for engine
ment. GASL Inc., of Ronkonkoma, New York, isthe cowl cooling for the Mach 7and 10flights.
scramjet and fuel system detail designer and builder.
Boeing North American of Seal Beach, California, is Measurements and instrumentation requirements for
providing vehicle aero/thermal/structural design and the Hyper-X flight test vehicle were established by a
analysis, TPS design and fabrication, and guidance, team composed of hypersonic technology "customers"
navigation, and control software and simulations. and flight test personnel. The former are primarily
Accurate Automation Corp. of Chattanooga, Ten- interested in determination of propulsion and vehicle
nessee, is responsible for instrumentation. On asepa- performance and obtaining local measurements for
rate contract, the Chandler, Arizona, Launch Systems validation of design methods (propulsion, aerodynam-
Group of Orbital Sciences Corporation will build the ic, thermal, structures and controls), whereas the latter
Hyper-X launch vehicles---a first stage derivative of are more concerned with monitoring vehicle systems
their Pegasus launch system--that will boost the for safety and understanding how the vehicle per-
Hyper-X vehicles tothe test conditions. In addition, forms, or identifying failure modes. The program
Orbital has major responsibilities for integration with intentionally utilizes proven, reliable instrumentation
the flight test vehicle and flight test support. methods, and a relatively small number of simple
(pressure, temperature and strain gage) measurements
Both contractors have completed Manufacturing to assure program schedule and cost goals. Off-the-
Readiness Reviews and are inthe process of purchas- shelf data system components are utilized to process
ing material and components, and starting manufactur- and telemeter measurements. A schematic of the data
ing. A program schedule, presented as figure 4, shows system ispresented in figure 11. Location/function of
that the Mach 7vehicle will be delivered in March
1998. Subsequent vehicles will be delivered in yearly
cycles. The first flight test isscheduled for July 1999.
The vehicle structural design and preliminary sys-
tems layout are presented in figures 9 and 10. The
vehicle structure utilizes metallic (largely aluminum)
keels, bulkheads and skins, all sized to meet vehicle
hat:
stiffness requirements. Thermal protection consists
of alumina-enhanced thermal barrier (AETB) tiles,
-"_------4 / -I-,. )
which have been fully characterized for the space
shuttle, carbon-carbon wing, tail and forebody nose
tIIri,_ru_ttn_ _ _natl
leading edges. The majority of the wings and tails are
high temperature steel. High pressure gaseous Figure 10. Hyper-X Equipment Layout
hydrogen (fuel), silane (scramjet ignition) and helium
',,_, :
....... ,
Figure 9. Hyper-X Structure, TPS, and Systems Figure 11. Hyper-X Instrumentation System
6
the measurements can be summarized as follows: scramjet can be operated. For safety, the gaseous
hydrogen fuel will be supplied from outside the tunnel
Airframe - surface 64
rather than from the vehicle's on-board fuel system. In
Engine surface 63
addition, data will be transferred using an umbilical
Airframe structure 55
hook-up rather than telemetry. In all other respects the
Fuel system 32
tested systems will be operated as they would be oper-
Control surfaces 10
ated inflight. Specifications call for each vehicle to be
Coolant/purge 17
capable of withstanding at least 10 thermal cycles in
the tunnel. This test also constitutes part of the pre-
02/fire detection 24
flight verification and validation testing checkout.
Inertial and time 17
Attitude 8
Each vehicle, in the interim between the 8' HIT tun-
Voltage/current 8
Miscellaneous 65 nel tests and flight test, will undergo a variety of
component and system preflight tests; first without
Of the 371 measurements, 115 are pressure, 96 are the HXLV (6 months), then with the HXLV (1
temperatures and 37 are strain gauge. The program is month), and finally mated to the B-52 (2 months).
also carrying 40 percent spares for growth potential. These tests include aircraft-in-the-loop (AIL) vehicle
integration, on/off conditions, and integrated engine
system tests, HXRV-HXLV integration, electromag-
Ground Tests of Vehicle netic interference (EMI) and combined systems tests.
Following B-52 mating, additional tests will include
After delivery, each vehicle will undergo extensive ground vibration tests (GVT), EMI, combined sys-
testing. In addition to normal validation and verifica- tems (CST) and taxi tests.
tion testing before flight, and integration and stage
separation tests, the Mach 7 and 5vehicles will be
tested at flight conditions (Mach, pressure and Vehicle Desitm Validation
enthalpy) in the Langley Research Center 8-Foot
High-Temperature Wind Tunnel (8' HTT, see figure Validation of the Hyper-X predicted performance
12). The objective of these tests is to provide propul- will be considered as validation of the design pro-
sive system verification, validate structural integrity, cess, and designs generated using these methods.
and verify operation of various components. This Figure 13illustrates results from the highest level
test provides flight test risk reduction and will allow tools used for design. This Reynolds Average Navier
comparison of the wind tunnel methods and results Stokes solution, produced using the GASP code (ref.
with flight performance. The resulting data will be 11), provides a complete solution of the flowfield of
directly compared with the in-flight measurements, the flight vehicle at the powered test condition, and
but more important, with prediction for the wind tun- was used to verify the performance predicted using
nel and flight environments. normal design tools (ref. 12).
Each vehicle isbeing designed for insertion into the Wind tunnel testing commenced in early 1996 to ver-
tunnel flow for a 30-second period, during which its ify the engine design, develop/demonstrate flight test
Figure 12. Hyper-X Installed in Langley 8-ft. Figure 13. CFD Solution for Powered Hyper-X
High Temperature Tunnel at Mach 7
engine
controls, develop experimental aero-dynamic A preliminary aerodynamic data base was developed
data bases for control law and trajectory development from results of 15 experimental programs on 11 sep-
and support the flight research activities. Mach 7 arate wind-tunnel models utilizing over 1,000 wind-
engine performance and operability was verified in tunnel runs. These tests were performed using 8.33%
reduced dynamic pressure tests of the "DFX" (dual- and 3.0% scale model tests of the Hyper-X research
fuel experimental) engine inthe NASA Langley Arc vehicle (HXRV) and the Hyper-X launch vehicle
Heated Scramjet Test Facility (ref. 1). Figure 14 (HXLV) booster stack models respectively at Mach
illustrates the extent of the full-scale, partial-width numbers of 0.8-4.6, 6and 10. The aerodynamic data
flowpath simulated in those tests. The shaded region base includes boost, stage separation, research vehi-
represents the DFX engine. Preliminary experimen- cle powered flight and unpowered flight back to sub-
tal results for the Mach 5and 10 scramjet combustor sonic speeds. The aerodynamic and propulsion data
design have been obtained using the direct connect base is being filled in with additional wind tunnel
combustor module rig (DCM) and HYPULSE facili- tests. Figures 15 and 16illustrate an 8.33 percent
ty in the reflected shock mode (ref. 13). Additional scale Hyper-X research vehicle model and a3per-
tests will be performed at Mach 7, 5 and 10 using a cent booster stack model respectively, both inthe
partial width, full scale engine segment, which incor- NASA LaRC 20- Inch Mach 6tunnel at Langley.
porates all variable geometry and cooling features of
the Hyper-X flight engine. These tests will include Other work leading up toHyper-X vehicle development
full dynamic pressure and enthalpy, and flight con- contract award included control law development, pre-
trois and/or flight control simulation. liminary trajectory evaluations (including some Monte
Carlo uncertainty analysis, using the methods demon-
strated in ref. 14) and aerothermal loads for the boost,
separation, and flight test portion of the flight. Prelimi-
nary control laws (ref. 15) were developed for feasibili-
tystudies. For the powered part of the trajectory, longi-
tudinal and lateral control laws were developed for
angle-of-attack (AOA) and side-slip control. These
include angle-of-attack and side-slip estimators which
utilize motion data, aerodynamic data and atmospheric
and flight condition data. Preliminary assessments of
N.-7 \
Flight _ flight trajectories and stability margins for the longitudi-
q..olO(X_f
nal control laws, using conservative structural bending
mode filters, demonstrate that the vehicle meets the
AHSTF DFX
flight test requirements. For example, figure 17pre-
*_•_ M1-62 "_Mt2),_ =Mz_,,_-X sents elevator position and angle-of-attack as afunction
_ "
of time, from stage separation through cowl closure.
, Full scale •Truncated forebody Initially the elevator controls are locked, and the vehicle
• Partial width • Truncated aftbody
isassumed to be at the launch vehicle stage separation
Figure 14. DFX Model Compared with Hyper-X condition of zero degrees AOA. Aerodynamic and sep-
Figure 16. Hyper-X 3% Aerodynamic Model
Figure 15. Hyper-X 8.33% Aerodynamic Model of Booster Stack Installed in Langley 20"
Installed in Langley 20" Mach 6 Tunnel Mach 6 Tunnel
8