A Review of United States Air Force and Department of Defense Aerospace Propulsion Needs (2006) / Chapter Skim
Currently Skimming:
1 Overview
1 Overview
Pages 11-66
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 11... ...
development plans. The recommendations in this report may shape DoD engine development planning for the next 15 years and, possibly, military capabilities beyond that.
|
From page 12... ...
. · Identify technical gaps and suggest rough order of magni tude (ROM)
|
From page 13... ...
If this were the real-world case, the committee's datagathering efforts would have been relatively straightforward. However, the committee members assigned this task found, with a few exceptions, neither well-defined capabilities nor realistic technology transition planning.
|
From page 14... ...
and Air Force Space Command (AFSPC) personnel, it became obvious that this strategy was not the determinant of their marching orders and was considered to be only one out of several strategies in play.
|
From page 15... ...
to replace low reliability parts; · Utilize evolutionary programs to develop reliable, efficient, low cost turbine engines; and · Minimize total life cycle cost. Cross-cuttingCapabilities/Needs · Stealth/survivability; -- Inlet/exhaust integration and flow control · Increased ranges and payloads; · Increased size of operational envelopes (missiles and air-breathing)
|
From page 16... ...
The committee's judgments are based specifically on data gathered about propulsion technology devel
|
From page 17... ...
However, the committee fears that basing important analyses of alternatives on less than fully considered cost and schedule realities does not serve decision makers well. Propulsion research It is clear to the committee that unless additional emphasis is placed on propulsion, the technological lead the United States has enjoyed for so long, and perhaps taken for granted, will cease to exist.
|
From page 18... ...
The overall DoD investment in PR from FY04 to FY07 remains fairly flat at around $400 million to $410 million except for a spike to $440 million in FY05.3 The flatness of the numbers does not give a true picture, however, particularly for 6.2 work, where the budgets in gas turbine technology from FY02 to FY06 were fairly flat but cover AFRL payroll and administration costs. While the amounts for in-house R&D remained fairly flat, the amounts for industrial R&D fell precipitously over the FY02-FY06 period.
|
From page 19... ...
The committee's Judgment The study statement of task required the committee to "identify technical gaps and suggest rough order of magnitude (ROM) , specifically applied S&T investments in these areas of propulsion." The committee based its ROM estimates on its collective judgment, which, in turn, was based on the members' extensive experience and expertise in aerospace propulsion.
|
From page 20... ...
Two main types of propulsion systems not in operation today will be required to provide this speed capability: gas turbine engines (GTEs) that operate in the Mach 3.6 to 4.2 range and ramjets/scramjets that operate in the Mach 4.0 to 16 range.
|
From page 21... ...
· "Disruptive" challenges require propulsion systems to power vehicles for directed-energy weapons or to counter directed-energy weapons. Propulsion technologies such as integrated thermal and power management, high-heat-sink fuels, and large electrical generating capacity are required to meet these threats.
|
From page 22... ...
Gas turbine engines will continue to play a dominant role in propulsion in future warfare. Their performance can be improved enough (15-20 percent)
|
From page 23... ...
To accelerate the development of new engine technologies, the Air Force gas turbine S&T funding should be increased significantly, from approximately $100 million annually to a level that reflects buying power at the time when the F-15 and F-16 engines were being developed. Top priority should be given to overcoming the technology barriers that will have the largest impact on future weapons systems: · Compressor discharge temperature limits, · Turbine inlet temperature limits, · High-temperature, high-heat-sink fuels for thermal management, · Lightweight structures, and · Signature control.
|
From page 24... ...
Current DoD funding for gas turbine S&T is much less than in the 1990s, and if it is not increased, the United States will probably lose its GTE technical advantage, as has happened in civil aviation. IHPTETandVAATEDemonstratorandResearchPrograms Since turbine engines are so critical to the capabilities of military aircraft, DoD has pioneered many advances through demonstrator and research programs such as its preeminent turbine engine research programs IHPTET and VAATE.
|
From page 25... ...
VAATE will also have similar spin-off benefits for turbine engines used in marine, ground transportation, and powergeneration applications. The original VAATE program, which would have allowed robust tech development, demonstration, and transition capability, was scheduled to be funded at $145 million in FY06 and $149 million in FY07.
|
From page 26... ...
recommendation 3-3. DoD should restore gas turbine S&T funding under the VAATE program to the original planned level.
|
From page 27... ...
27 on dorF ter Car member staff C NR to AFRL, urns,By Larr omfr communication ersonalP CE: AFRL/WS06-0065.yb SOUR ust. eleaser thr public engine for in edvo ess ogrrP pprA 1-1 2006.
|
From page 28... ...
Near-term opportunities exist to incorporate existing GTE technologies into this fleet to significantly reduce the cost of sustainment and decrease the amount of fuel burned. The committee saw many examples where CIPs, derivative engine programs, and engine capability enhancement programs (ECEPs)
|
From page 29... ...
This reduced cost and shorter time for development mitigates the cost and schedule risks of weapons system development. Small gas Turbine Engine Programs This section reflects the committee's views on the status, requirements, and anticipated plans for small (500-15,000 shaft horsepower (SHP)
|
From page 30... ...
DemonstrationPrograms Past science and technology programs have demonstrated significant advances in the capabilities of turboshaft engines. Specific improvements are expected to lead to smaller, lighter, more affordable rotorcraft and UASs.
|
From page 31... ...
Two new small military gas turbine engines -- 3,000-SHP and 10,000-SHP class -- are needed to meet the mission requirements of all the military services.
|
From page 32... ...
Given the criticality of the high Mach number cruise missile, DoD should support the success of these system demonstrations by funding programs to ensure the availability of high-temperature materials. other Technology Programs for aerospace Propulsion There is a general perception that aeropropulsion is a mature, plateau technology.
|
From page 33... ...
RamjetandScramjetEnginePrograms Scramjet propulsion is crucial for standoff strikes on time-critical and hardened targets, boost-phase intercept, and flexible access to space using airplanelike operations. Although the first patent on ramjet propulsion (René Lorin)
|
From page 34... ...
, to be used on a liquid hydrocarbon scramjet engine with a solid booster, and (2) the Falcon, to be used on a hydrogen scramjet engine with a rocket motor.
|
From page 35... ...
There are alternative solutions for both time-critical, hardened targets and flexible space warfare, and these should also be studied and compared with the scramjet solution. rockET ProPuLSIon SYSTEMS For accESS To SPacE anticipated Military Spacelift Propulsion needs and Identification of critical Technologies In early 2005 the U.S.
|
From page 36... ...
The committee does not believe that the Air Force will be able to reliably and cost-effectively transform U.S. military space transportation capabilities by focusing on pushing high-thrust rocket propulsion technologies to their limits.
|
From page 37... ...
The RS-68 was ultimately selected to power the Delta family of evolved, expendable launch vehicles (EELVs) developed for the Air Force by the Boeing Space Systems Company.
|
From page 38... ...
AerojetRocketBoosterforAtlasVLaunchVehicle The solid rocket strap-on booster motor for the Lockheed Martin Astronautics Atlas V EELV has been developed, flight qualified, and produced by Aerojet. This new generation of solid rocket motors provides
|
From page 39... ...
The Atlas V family of launch vehicles will use from one to five strapon solid rocket motors depending on the mission and the launch trajectory requirements. The solid rocket motors are ignited at liftoff and burn for over 90 sec; each motor provides a thrust in excess of 250,000 lbf.
|
From page 40... ...
Responsive spacelift is shown in the DoD space transportation roadmap, Figure 4-1. It was thought that two or three small launch vehicles would be flown in the demonstration phase, 2004 through 2009.
|
From page 41... ...
Its overall goal is to develop and validate in-flight technologies that will enable both near-term and far-term capabilities to execute time-critical, prompt, global-reach missions while at the same time demonstrating affordable and responsive spacelift. The technical underpinning of the FALCON program was that a common set of technologies could be matured in an evolutionary manner that would provide a near-term (circa 2007-2010)
|
From page 42... ...
DARPA should continue to fund and monitor this company to completion of the FALCON program objectives. The Air Force should evaluate the propulsion technologies to be demonstrated for the air-launched FALCON vehicle and include them in total system studies of options for ORS vehicles.
|
From page 43... ...
Finding 4-6. Configurations for candidate launch vehicles (including parallel boosters or strap-on combinations)
|
From page 44... ...
Integral to the total systems engineering process is verifying that the design criteria for all proposed critical technologies have been validated. This is the main thing that allows objective evaluations of development engineering schedule and cost risks and of propulsion systems' operational and life-cycle cost risks.
|
From page 45... ...
To proceed confidently with competitive conceptual designs for the vehicle prototype starting in 2005 and then implement a selected configuration development program starting in 2006, the selection of propulsion technologies might have benefited, from a total systems engineering perspective, from incorporating those technologies in existing qualified propulsion elements or those with extensive validating data. The committee found no sign of any transformational or revolutionary technologies that were mature enough to be considered for ARES, so they would presumably not be used in the full-scale vehicle that is expected to emerge from the subscale demonstrator.
|
From page 46... ...
Initiatives for developing new aerospace Propulsion Technology NationalAerospaceInitiative The NAI began in 2001 as a joint technology program by DoD and NASA. It is not to be thought of as a system development or acquisition program (NRC, 2004)
|
From page 47... ...
It is a joint government-industry effort focused on affordable technologies for revolutionary, reusable, and/or rapid-response, global-reach military capabilities. It addresses sustainable strategic missiles, long life or increased maneuverability, spacecraft capability, launch vehicle propulsion, and high-performance tactical missile capability.
|
From page 48... ...
In general, the development of rocket propulsion technology by the United States for all spaceflight applications has significantly lagged development by the rest of the world since the initial certification of the space shuttle. This lack of progress in rocket propulsion technologies over such a long period has resulted in several deficiencies in the nation's space program.
|
From page 49... ...
ability to meet DoD's propulsion needs for a new ORS family of vehicles starting with ARES in about 2015. Basically, the nation's current capabilities in space propulsion and space transportation are but a fraction of the capabilities that were evolved starting in 1954 for the ICBM program and culminating in the early 1970s with the end of the Apollo program.
|
From page 50... ...
for a new operationally responsive family of spacelift vehicles, starting with ARES in 2010 and ORS in 2015. DoD and Air Force commitment to fully develop these new robust launch vehicles might help rejuvenate the U.S.
|
From page 51... ...
current Propulsion Technologies ChemicalPropulsion The conventional chemical liquid propellant propulsion systems now in use are either monopropellants or bipropellants. Liquid bipropellant systems are better performers but are more complex and deliver a fuel and oxidizer mixture that reacts chemically in the combustion chamber.
|
From page 52... ...
. Historically the PPU has been the dominant cost driver for electric propulsion systems because it calls for heavy power converters and thermal management systems.
|
From page 53... ...
OVERVIEW 53 current Propulsion research In 1994, DoD, the Air Force, and NASA established the IHPRPT program. This joint government and industry effort includes developing technologies for extending the life of spacecraft and for in-space maneuvering of various assets.
|
From page 54... ...
ElectricPropulsion Electric propulsion projects already carried out or in progress under IHPRPT include the following: · Orbit insertion: 4.5-kW Hall-effect thrusters, 25-cm xenon ion thruster, 20-kW Hall-effect thrusters, and XOCOT (type of pulsed plasma thruster)
|
From page 55... ...
Velocity changes of hundreds of feet per second could be achieved in minutes to hours, permitting position changes of thousands of miles per day. A third way to implement large, rapid station changes would be to have a space tug with either high-performance electric propulsion for slow strategic moves or high-thrust, modest-performance chemical propulsion for responsive maneuvers.
|
From page 56... ...
Most of the IHPRPT funding for solid rocket technology has been for strategic sustainment to maintain some level of capability and industrial base. For one reason or another, none of the few advanced propulsion technologies that have demonstrated significant improvements has been transitioned into an operational system to date.
|
From page 57... ...
However, as already stated, these technologies have not yet been transitioned into any operational system. current IHPrPT research Missile propulsion technology work under IHPRPT is divided into three categories: solid propellant motors, hybrid rocket motors, and gelled propellant motors.
|
From page 58... ...
Thrust profiling for either ground- or airborne-launched missiles can be provided by using solid propellant motors with a variable area nozzle, hybrid solid fuel with gelled storable oxidizer, or gelled storable liquid propellants. HybridRocketMotors Lockheed Martin Michoud Operations has worked on hybrid propulsion technologies since 1989.
|
From page 59... ...
The Air Force and DoD should sponsor a detailed system engineering study of using the MMMV air-based launch system for medium-sized missiles in combination with the air-based vertical launch study for various types and sizes of missiles called for in Recommendation 5.5, thereby ensuring that both studies are focused on the Air Force/DoD optimization criterion "mission success." The studies would identify the propulsion technologies (modifications or new concepts) that should be evolved in order to take full advantage of such air-based launch platforms for operationally responsive missions.
|
From page 60... ...
This limits the accomplishments of propulsion improvement efforts and minimizes the opportunity to train the next generation of designers and production specialists. Personnel demographics indicates that many individuals with critical skills in the development and production of large missiles and launch vehicles will retire in the same time frame.
|
From page 61... ...
Since the DoD production base is not large, these new material technologies only become economical if there are commercial applications. This presents an opportunity for realistically planned ManTech programs that will provide baseline manufacturing technology for high-performance defense systems and also leverage requirements of the nondefense aerospace sector (DSB, 2006)
|
From page 62... ...
A small share of the savings in sustainment and fuel costs of existing aircraft generated by IHPTET could be allocated to properly fund VAATE, which requires approximately $300 million per year focused on warfighter needs if the United States is to maintain its lead in gas turbine propulsion. The legacy fleet, which will make up over 80 percent of the 2018 warfighting capability (if the Joint Strike Fighter is included)
|
From page 63... ...
For example, propulsion systems for the F-16 and F-15 aircraft underwent spiral development programs to improve their thrust and reliability, a very cost-effective way to increase their warfighting capability.The main derivative programs for these engines (e.g., F100-220 and -229 versus the F100-100) bundled technology packages from IHPTET or IR&D programs to markedly enhance performance.
|
From page 64... ...
2003. Air Force Space Command Strategic Master Plan FY06 and Beyond.
|
From page 65... ...
U.S. Space Transportation Policy.
|
From page 66... ...
66 AREVIEWOFAEROSPACEPROPULSIONNEEDS chapters 2-7 and appendixes a-E are reproduced on the cd-roM that contains the full report but are not included in the printed report.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.