ADVANCED AND UNCONVENTIONAL EARTH-TO-ORBIT TRANSPORTATION CONCEPTS Robert H. Frisbee Soon to be Retired Jet Propulsion Laboratory As of 9-25-09, Home contact info: 4837 Alminar Ave., La Canada CA 91011 (818) 790-0508, FAX (818) 790-9678 [email protected] Presented at the Advanced Earth-to-Orbit Transportation Workshop National Institute of Aerospace Hampton VA 23667 September 3, 2009 OUTLINE • Introduction to the Problem • Focus Categories • Increasing Isp • Reducing system mass • Breakthrough physics • Reducing system costs • Evolutionary (incremental) versus Revolutionary • Infrastructure-Rich Systems • Beamed Energy (Laser, Microwave) • Launch Assist Catapults • Non-Propulsive (Tethers, Skyhooks, Towers) • Breakthrough Physics • Minimal-Infrastructure Systems • Advanced High Energy Density Matter (HEDM) Chemical • Nuclear • Aerial refueling • Summary and Recommendations 1 Introduction THE PROBLEM: LAUNCH COSTS > $10,000/kg GOAL: Reduce Costs Examples from the 1990s 2 Introduction THE PROBLEM: MISSION CAPABILITY GOAL: Enable New / Impossible Missions Mission V vs Propulsion Energy Density Mb /Mo = EXP( –V/Vex ) = EXP( –V/Isp ) You Are Here 2 2 3 2 E = M Vex = M Isp Introduction THE PROBLEM: NEED ADVANCED PROPULSION TECHNOLOGY BUT - IT TAKES TAKES TIME AND $$$ • Typically takes decades to go from concept to flight • Basic research often tied to grad student life cycle (e.g., 4+ years) • Costs dramatically increase over development life • $100K for "paper" studies, basic research -> $100M for space flight demo • Flight demos (e.g., New Millennium DS-1 SEP) critical for acceptance • Project Managers very risk adverse • Nothing succeeds like success - Proposals now being funded for SEP missions (e.g., Dawn SEP) Initial Concept - - > Initial Development - - > Flight Tsiolkovsky Routine Human STS Spaceflight DS-1 Dawn Ion 1903: Znamya Cosmos LO2/LH2 Rocket The Rocket Equation Solar Sails DV = Isp * ln(Mfinal/Minitial) 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year 4 FOCUS CATEGORIES Category Top Ten Enabling Techs Other Enabling Techs Increasing Isp • Nuclear Fission • Pulse detonation • NERVA, PBR • New liquid rocket engine cycles • HEDM • Air-Breathing • RBCC et al. • MHD-Augmented Reducing • Beamed-Energy • Lightweight rocket engines System Mass • Laser, microwave • Launch assist (MagLev) • Ultra-high strength/weight, • Large scale launch assist, Space Elevator smart materials • New materials • Autonomous / remote-piloted flight • Lightweight power Breakthrough • Energy Physics • Propellantless levitation Reducing • Ultra-low-cost • Cryogenic RCS System Cost manufacturing • Self-healing TPS • Low-cost airframe manufacturing • Modeling/simulation • Integrated health management • Reduced turn-around time 5 EVOLUTIONARY (INCREMENTAL) VERSUS REVOLUTIONARY • Sorry folks - Most of these are “product improvement” • All you will ever get is modest, few percent improvements, NOT orders-of magnitude - - - Need new ways of doing “business” Tech. Type Top Ten Techs Other Techs Additional Techs Category Evolutionary Revolutionary Increasing Isp • Nuclear Fission: Upper stages • HEDM: Single-stage to GEO • HEDM: Additives • Nuclear Fission: Orion ETO • Pulse detonation • Aerial refueling • Lightweight rocket engines • Air-Breathing (RBCC et al.) • New liquid rocket engine cycles • MHD-Augmented Reducing • New/advanced materials • Beamed-Energy (Laser, microwave) System Mass • New/advanced engines, Power • Launch assist (MagLev) • Autonomous / remote-piloted flight • Large scale launch assist, Space Elevator • Launch assist combinations Breakthrough • Energy, Propellantless levitation Physics • No love for Wormholes? Reducing • Ultra-low-cost manufacturing System Cost • Cryogenic RCS • Self-healing TPS Infrastructure Rich • Modeling/simulation Minimal-Infrastructure • Integrated health management • Reduced turn-around time 6 ADVANCED / UNCOVENTIONAL REVOLUTIONARY CONCEPTS Focus of this presentation: • Some additions to the list, some already identified • Re-arrange into Infrastructure-Rich versus Minimal-Infrastructure • Top Ten Techs Other Techs Additional Techs • Infrastructure-Rich: Typically reduce system (dry) mass • Beamed-Energy (Laser, microwave) • Launch assist (MagLev) • Large scale launch assist, Space Elevator • Launch assist combinations • Wormholes? • Minimal-Infrastructure: Typically increase (effective) Isp • HEDM: Single-stage to GEO • Nuclear Fission: Orion ETO • Aerial refueling 7 INFRASTRUCTURE-RICH SYSTEMS OVERALL OBJECTIVE • Take the “propulsion system” off of the vehicle and place it on the ground (or in a permanent orbit) - easier to build, maintain • Amortize initial infrastructure investment over many launches State-of-the-Art System Total System Advanced Mass, Technology Cost System Cross-Over Mission “Size” (Payload Mass, V, Number of Missions) MAJOR ISSUE - Who pays for the initial (set-up) “infrastructure” EXAMPLES OF INFRASTRUCTURE-RICH SYSTEMS • Beamed Energy (Laser, Microwave) • Launch Assist Catapults (Cannon, MagLev) • Non-Propulsive (Tethers, Skyhooks, Towers) • Breakthrough Physics 8 INFRASTRUCTURE-RICH SYSTEMS BEAMED ENERGY AS A SPACE POWER GRID The Vision - - BUT - - Who pays for the Infrastructure ? 9 INFRASTRUCTURE-RICH SYSTEMS EARTH-TO-ORBIT BEAMED ENERGY PROPULSION • Use laser (visible or near-IR) or microwave beamed energy • Transmission "Station" can be ground- or space-based • Use energy to heat on-board and/or atmospheric propellant • Potential to reduce launch cost, more frequent launches • Potential for very large infrastructure (big, high-power laser "Station") • ~1 MW beam power per kg of vehicle mass Space-Based Beamed-Energy Station / Transmitter THE VISION PRIOR RESEARCH Laser-Supported AIR FORCE PHILLIPS LAB, NASA, RPI Propulsion 8” LASER LIGHTCRAFT Ground-Based Beamed-Energy Station / Transmitter Earth 10 INFRASTRUCTURE-RICH SYSTEMS BEAMED ENERGY CONCEPTS SUMMARY • No capability for LEO missions within 10 years • Transmission through atmosphere seems doable • Thermal blooming not an issue at beam intensities (W/m2) required for space transportation/power applications • Correct for atmospheric turbulence with adaptive optics and “cooperative” target feedback • Major concern over infrastructure (beam transmission station) due to high beam powers required for Earth launch (~ MW/kg) • Pulsed GW-class microwave further along than lasers (but need big optics for microwave systems) • High powers not needed for orbital transfers • Suggests a possible technology ''growth'' roadmap: Solar Thermal Orbit Laser Thermal OTV Laser / Microwave L/V Transfer Vehicle (OTV) (Beam P ~1-10 MW (Beam P ~ 1-100 GW) • In the far-term, even if technical obstacles can be overcome, economic feasibility a strong function of launch rate • Must be a demand for large numbers of payloads to amortize infrastructure 11 INFRASTRUCTURE-RICH SYSTEMS LAUNCH ASSIST CATAPULT CONCEPTS The classic Jules Verne approach 12 INFRASTRUCTURE-RICH SYSTEMS LAUNCH ASSIST CATAPULT CONCEPTS COMPARISON - CAPABILITY VERSUS REQUIREMENT - All the You good are stuff’s here here 13 INFRASTRUCTURE-RICH SYSTEMS LAUNCH ASSIST CATAPULT CONCEPTS SUMMARY • No capability for LEO missions within 10 years • Marginal capability for suborbital launch with cannons and light gas guns within 5 years • Cannons (e.g., HARP): Cost, complexity, and limited size (mass and volume) of high-gee payloads and on-board prop. systems may outweigh any potential launch cost savings • Light Gas Guns: Can scale up for big, modest-gee payloads, but at added cost) • MagLifter may enable SSTO rocket by reducing rocket’s V • Potentially “easiest” launch assist catapult for reasonable-sized payloads (including human) - smallest leap from existing MagLev train technology • BUT - Need SSTO vehicle • In the far-term, even if tech. obstacles can be overcome, economic feasibility a strong function of launch rate • Must be a demand for large numbers of payloads to amortize infrastructure 14 INFRASTRUCTURE-RICH SYSTEMS NON-PROPULSIVE CONCEPTS (TETHERS, TOWERS, SPACE ELEVATOR) • Major paradigm shift in the concept of ''launch vehicle'' • Use momentum instead of rockets • Potential for really large infrastructure (Space Elevator) Geoff Landis (NASA GRC): IAF-95-V.4.07, AIAA-98-3737 15 INFRASTRUCTURE-RICH SYSTEMS HYBRID SUBORBITAL LAUNCH + ROTATING LEO TETHER MAY ENABLE SSTO ISSUE • Space Elevator (SkyHook) potentially lowest “launch” cost ($/kg) • BUT most demanding cable materials (unobtanium) • AND potentially largest infrastructure of all, • AND who pays to build the entire Interstate Highway system before the first $ of revenue is collected??? (Sound familiar?) POSSIBLE HYBRID SOLUTION • Combine suborbital launcher (catapult launcher, high-altitude hypersonic airplane) with LEO-based rotating tether • Match altitude and horizontal velocity at top of suborbital trajectory to the tip speed and altitude of rotating tether (Bolo) to “fling” payload to LEO velocity • Dramatically lessens requirements compared to “pure” system • SSTO launch vehicle only suborbital (lower V) • Launch assist catapult lower muzzle velocity • Rotating tether rather than full Space Elevator • Extreme limit: Use ultra-tall tower + rotating tether (Bolo) • Still fairly large infrastructure 16 INFRASTRUCTURE-RICH SYSTEMS NON-PROPULSIVE CONCEPTS SUMMARY • Capability for LEO orbit raising already demonstrated (TSS-1), but no capability for ETO missions within 10 years • SkyHooks require C-C nanotubes (bare minimum) or diamond (better) cables • Nanotubes progressively growing in length, approaching