NRC Workshop on NASA Technology Roadmaps TA01 - Launch Propulsion Systems

1. NRC Workshop on NASA Technology RoadmapsTA01 - Launch Propulsion Systems Randy Kendall General Manager Launch Systems Division The Aerospace Corporation 23 March 2011

2. 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

3. 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

4. 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

5. 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

6. LH TBCC LH TBCC LH ACES LH RBCC LH Rocket LH RBCC LH Rocket RP RP LH RP LH LH RP LH LH RP RP 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

7. 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

8. Backup

9. 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.