Reusable Booster System Review and Assessment (2012) / Chapter Skim
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2 Air Force EELV-Class Launch Requirements and Approaches
2 Air Force EELV-Class Launch Requirements and Approaches
Pages 10-22
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From page 10... ...
2.1 SUMMARY Evaluation of alternative launch and upper stage options for Evolved Expendable Launch Vehicle (EELV) -class missions is the focus of this report, and nominal EELV mission frequencies and payload masses were briefly cited in Chapter 1.
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From page 11... ...
As discussed in Chapter 1, the RBS concept involves a reusable first stage (or two first stages in the heavy-lift variant shown in Figure 2.1) , which separates from one or more expendable upper stages at velocities between Mach 3.5 to 7 and then returns to the launch base by a "rocketback" maneuver using one of the first-stage rocket engines.
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From page 12... ...
Note that the RBS launching of Evolved Expendable Launch Vehicle heavy payloads requires the added complexity of parallel staging of the first stage boosters. SOURCE: Air Force Space and Missile Systems Center, "Reusable Booster System Costing, SMC Developmental Planning," presentation to the committee, February 15, 2012.
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From page 13... ...
FIGURE 2.3 Comparison of the vehicle life cycle and recurring cost. For the Air Force projected launch rate of 8 to 12 per year, the reusable booster system recurring costs projected by the Air Force Space and Missile Systems Center are approximately $40 million less per launch than the costs with expendable launchers.
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From page 14... ...
These include risks associated with the rocketback maneuver, staging of asymmetric or parallel vehicles, first- and second-stage hardware developments, additional operations, achievement of desired operational efficiencies, and projected costs. 2.3 RBS TECHNICAL PROGRAM SUMMARIES This section and those that follow it will provide brief descriptions of major technical elements of the baseline RBS program, including flight operational vehicles, research and development (R&D)
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From page 15... ...
occurs 83 nmi downrange at altitudes between 200,000 and 250,000 ft. In general, typical staging velocities are between Mach 3.5 and 7 as lower staging velocities tend to require very large upper stages, and higher staging velocities subject the first stage to atmospheric heating and structural dynamic environments that demand increased thermal protection, more stringent structural requirements, and higher operating costs.
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From page 16... ...
However, higher separation vector editable velocities drive requirements for thermal protection on the reusable first stage, which increases stage mass and significantly degrades ground operational efficiencies. After staging, the expendable upper stages deliver the payloads to appropriate orbits.
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From page 17... ...
27 Futron Corporation, "Design Reliability Comparison for SpaceX Falcon Vehicles," November 2004. 28 Pratt and Whitney Rocketdyne, "Reusable Hydrocarbon Rocket Engine Maturity for USAF RBS," presentation to the Committee for the Reusable Booster System: Review and Assessment, February 16, 2012.
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From page 18... ...
Unlike the EELVs, the first-stage booster will require its own avionics; but the LES software functions will be similar to those for EELV upper stages. 2.3.1.4 Operations The RBS baseline operations requirement is efficient accommodation of an average of eight launches per year from the Cape Canaveral Air Force Station (CCAFS)
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From page 19... ...
2.3.2.2 RBD Demonstrator Flight Vehicles The RBD is a step between the RBS Pathfinder and the operational RBS and is presently less well defined than RBS Pathfinder. Its primary purpose is to demonstrate the rocketback and RTLS maneuvers with a vehicle more closely representing the full-scale RBS booster and to demonstrate rapid ground processing operations for 42 AFSMC, "Reusable Booster System Costing, SMC Developmental Planning," 2012.
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From page 20... ...
However, the present RBS Pathfinder program would downselect to a single contractor after completion of the Phase 1 effort described above.50 The number of suppliers for major operational RBS elements is presently unknown, but the available costing data for the baseline RBS program do not assume multiple suppliers of those systems. This suggests that at the conclusion of a successful RBS program, the industrial base for RBS EELV-class missions would resemble that supporting the present EELV program.
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From page 21... ...
The upper stages of the RLVs were designed to be recoverable, which implies they must accommodate very stressing reentry environments. Relative to the RBS vehicle approach, this adds complexity and mass to the upper stages and, in practice, increases ground operation requirements and costs.
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From page 22... ...
Lockheed NASA Y Total SSTO LEO Y SSTO Martin vehicle Linear Aerospike Engine X-33 Thrust Modulated TVC EMA Kistler Multiple Y 1st and TSTO LEO to Y Reusable TSTO K-1 2nd stages GEO Land Recovery SpaceXd Multiple Y 1st and TSTO LEO to N Falcon 9 2nd stages GEO RBS Air Force N 1st stage TSTOe LEO to N Reusable LO2/RP-1 ORSC rocket engine only GEO Rocketback Maneuver RTLS Ground Processing Operations a Booster vehicle designed for potential transport of crew. b Solids recovered down range.
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