© The Aerospace Corporation 2011

NRC Workshop on NASA Technology Roadmaps

TA01 - Launch Propulsion Systems

Randy Kendall

General ManagerLaunch Systems DivisionThe Aerospace Corporation

23 March 2011

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What technologies should NASA invest in?

• What is the mission?– Safe, reliable, affordable access to LEO

– Enabling exploration missions

– Point-to-point suborbital transportation

• What is the timeframe?– Near-term

– Mid-long term

• What are the figures of merit?– Potential for game-changing transformational capabilities

– Synergy with National Security Space missions

– Encouraging commercial market

– Strengthening industrial base

– International partnerships

3Launch, Strike & Range / Development Planning & Architectures

Near Term Needs

• Cost reduction is critical to all NASA, NSS and commercial objectives • Current access to LEO is safe and reliable, but expensive• Significant cost reduction requires increased flight rate of reasonably

sized payloads• NASA exploration initiative also requires new capabilities:

– Current baseline to meet large up-mass requirement accomplished by large expendable (80 to 120 MT) heavy-lift launch vehicles

• Complementary or alternative approaches include:– On-orbit propellant storage and transfer technology (either LV-to-LV

transfer or depots) to greatly increase lift capacity over single launch– Reducing need for heavy lift (esp. for unmanned & unoccupied elements)– Advanced in-space propulsion such as 200+ kW Solar Electric Tugs

• Key to routine, low-cost, reliable space access is reusability and operability

Reusability, robust infrastructure supported by in-flight propellant transfer and high performance in-space propulsion should be a key

focus

4Launch, Strike & Range / Development Planning & Architectures

Launch Technologies to Enable Partial Reusability

• 2003 USAF Operationally Responsive Spacelift AOA showed reusable booster stage optimal for reducing launch cost and improving routine space access

– Reusable Booster System (RBS) is AF solution– RBS addresses major subset of technology base for full reusable system

• RBS offers direct benefits to NASA, NSS, and Commercial Space– For payloads up to 77,000 lbs to LEO RBS reduces launch cost by 50%• Satisfies launch needs of NSS, commercial, and non-exploration NASA missions

• Approximately 50-70% of NASA Exploration launch mass is propellant that could be launched in increments

• Many exploration elements can launched (dry) as originally designed or (re)packaged within this capability

– For remaining payloads that exceed 77,000 lbs dry:• Additional RBS boosters could be employed or RBS family scaled to meet needs.

– For crew, potential for significantly improved reliability and safety due to inherent features of reusable system

RBS is key element of infrastructure to support routine low cost space access; NASA should look for partnership opportunities to better leverage RBS effort

5Launch, Strike & Range / Development Planning & Architectures

Key Propulsion Technologies to enable RBS Capability

• Hydrocarbon staged combustion engine– AFRL has initiated Advanced Hydrocarbon Boost Program to develop

technologies for long life, highly operable, reusable engine to support RBS– Potentially also a replacement for RD-180 on Atlas V

• Other supporting propulsion technologies:– Integrated vehicle/propulsion system aerodynamics and control – New LOX/LH2 second stage engine • Potentially modernized derivative of J2S used for Apollo third stage

– Long life components and systems– Fuel delivery, mixing, and combustion– VMS/IVHM sensors - nonintrusive propulsion and system level– Propellant Management - slosh analysis and control– Non-Toxic RCS - including methane/GOX, and non-toxic hypergols

 

No. 1 Priority is Advanced Hydrocarbon Booster Engine

6Launch, Strike & Range / Development Planning & Architectures

Key Launch Propulsion Technologies - Mid to Far Term

• Aerospace IR&D study looking at most promising technologies for “Beyond Next Generation” access to space

• Beyond RBS, fully reusable two stage to orbit (TSTO) further reduces cost, increases flexibility

– If flexible access to LEO is critical, vertical takeoff horizontal landing (VTHL) TSTO solutions appear best

• Booster stage based on RBS design

• Orbiter stage either fully reusable rocket or higher-performing but more technically advanced rocket based combined cycle (RBCC)-powered stage

– For hypersonic cruise, horizontal takeoff turbine-based combined cycle (TBCC) and Pulse Detonation Engine (PDE) solutions most promising

– For integration to traditional airport runway operations and air traffic control, concepts employing air collection and enrichment systems (ACES) look most attractive

• No quantity-distance issues as they take off with no onboard oxidizer

• They can live within existing runway limits

• ACES-based systems also show merit with mid-term air-breathing designs

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7Launch, Strike & Range / Development Planning & Architectures

Summary

• Launch cost reduction, without sacrificing reliability, is critical to enabling all future space operations objectives

• Reusability is key to both lower cost and reliability

• Critical near-term technologies for RBS– Hydrocarbon booster engine– Integrated vehicle/propulsion system aerodynamics and control – New LOX/LH2 second stage engine

• High leverage mid-far term technologies for full reusability– VTHL TSTO with RBS and RBCC

– HTHL with PDE and TBCC

– HTHL with ACES

8Launch, Strike & Range / Development Planning & Architectures

Backup

9Launch, Strike & Range / Development Planning & Architectures

Other Propulsion Technologies to Enable Mid-Far Term

• Thermal management (coatings, active, passive, materials)– PDE has advantages in this area due to time-averaged heat load

• High-temp seals and actuators (barn doors)– Including leak prevention and isolation

• Fuel delivery, mixing, and combustion • Mode transition and transient operation (single and parallel flow paths)• VMS/IVHM sensors (non-intrusive propulsion and system level)• Airframe integration/system integration• Rapid vehicle turn and operability technologies (leak-free joints, IVHM,

access provisions, robust designs, minimum fluid types, etc.)• Advances in CFD modeling for internal and external flowfields• Application of Carbon nanotube based structures to propulsion elements

A wide range of generic technologies are required to support the range of mid to far term launch options; however these generic technologies have significant concept specific differences/challenges that cannot be ignored in any focused development effort.