Horizontal_Launch_-_a_Versatile_Concept

Tec hnolo g y Tr ades

SummaryResults of theoftradesTechnologyshowed Trademixed resultsResults. As shown in Tables 9 through 11, certain tech- nology insertions could achieve increased payloads without significant cost increases; or conversely, costs could decrease without a decrease in payload. Benefits of varying degrees were predicted for aerial fueling, ACES, aluminum-lithium tank materials (Al2195 and Al2050), composite tank materials and out-of-autoclave fabrication, shape memory actuators, and adap- tive manufacturing. The remaining technologies were not strong drivers of increased payload within the constraints of this study and drive up overall lifecycle costs in almost all circum- stances. Many of these technologies will certainly be valuable in other applications, but this set of constraints—specifically, a campaign of 120 total flights—limits their cost effectiveness for horizontal launch.

WiththeexceptionofaerialfuelingandACES,allofthetechnologiestradedinthecurrentstudy were as applicable to vertical launch and other aerospace systems as they were to horizontal launch. Aerial fueling and ACES were specific to horizontal launch and have the potential to yield substantial payload increases at lower costs per pound of payload. Aerial fueling was especially powerful because there was little added cost to employ the technique in any hori- zontal launch operation.

The technology for ACES promises an effective increase in payload, although at higher cost and greatertechnicalriskascomparedtoaerialfueling.ImplementationofACESwillrequiredesign changes on both the carrier aircraft and the launch vehicle, while aerial fueling of the carrier aircraftcouldbeincludedinabaselinevehicleconceptimmediately.Eitherorbothtechnologies could be added as block upgrades with only moderate impact to an operational system.

Because low launch rates forced the use of expendable launch vehicles in this study, it was diffi- cult to find many technologies that could “buy their way” into the point designs. Some tech- nologies that were expected to have significant advantages did not demonstrate improvements in this analysis. Among these were improved rocket engines, other advanced propulsion tech- nologies, and improved propellants. Although the model predicted increased payloads for these technologies, the model also predicted very high costs.

Chapter 5

Table 9 Technology Trade Results as Applied to PD-1—Solid rocket system

(Each trade made separately against the system baseline)

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Tec hnolo g y Tr ades

Table 10 Technology Trade Results as Applied to PD-2—RP/LH2 system

(Each trade made separately against the system baseline)

Chapter 5

Table 11 Technology Trade Results as Applied to PD-3—2-stage LH2 system

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Tec hnolo g y Tr ades

Chapter 6

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CHAPTER 6

FLIGHT TEST SYSTEM CONCEPTS

The study team determined the critical development risks for the proposed system concepts and identified flight demonstrations as mitigation strategies. Two flight test system concepts (FTs) were developed to define design requirements and program costs. The results of this exercise serve to quantify the next steps required for the development of a national horizontal launch capability.

FlightTheflightTesttestSystemconceptsConceptwerederivedConfigurationsbymodifyingexistingexpendable,verticallaunchvehicles to produce horizontal launch vehicles. Two existing launch vehicles were used as baselines, and modified for horizontal launch. (See Table 12.) The carrier aircraft for both was the 747-100 SCA-905. As modified, this aircraft was assumed to have a total length of 231 ft, a wingspan of 196 ft, and a design payload capacity of 192,000 lb.

The analysis followed the same methods as for the point designs to determine weight, develop- ment costs, and reliability. Flight test costs were based on current production costs, operations costs, and an estimate of government and contractor flight test support requirements based on pastprograms.

Table 12 Summary of Flight Test System Concepts

Flight Test Demonstrator 1

MAIN WING

CASTOR 120

Solid Rocket Motor (ATK)

INTERSTAGE

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PAYLOAD

Deliver payload to target circular LEO at 100 nmi altitude and 28.5° inclination

Performance data is shown for due East launch from 28.5° latitude

747-100SCA-905carrieraircraft/4-stagesolidlaunchvehicle

FT-1consisted of the 747-100 SCA-905 carrier aircraft and a multistage solid launch vehicle. This approach was selected to minimize

DDT&E costs. The launch vehicle configuration was a Taurus XL rocket modified for the demonstration vehicle. It consisted of a Castor 120 stage, an Orion

50S XLG stage, an Orion 50XL stage, and an Orion 38 kick stage, for a total of four stages. The wing and empennage were attached to the first stage with a strongback. Structural modifications are required to adapt the exisitng attachment hardware, designed specifically for the Space Shuttle Orbiter, to the demonstration vehicle. All interstages, fairings and aerodynamic surfaces were composite materials. Power and attitude control subsystems were based on existing systems.

Flight Test Demonstrator 2

MAIN WING

MERLIN 1C ENGINE

SpaceX

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