1. A GenCorp Company High Thrust In-Space Propulsion Technology Development R. Joseph Cassady Aerojet 22 March 2011

2. 2 Technology Development Needs a Framework Critics attack the technology development efforts because they tend to “wander in the desert” Lack of a defined destination is cited as a flaw by the critics It is important to include ties to examine technologies with a framework that allows their relative merits to be examined in an applied manner – not abstract academic considerations! In this same vein, it is important to look for synergies between technologies. This should be a Figure of Merit (FOM) Elements that serve as building blocks and that are useful to multiple missions / destinations are also desireable – this is another key FOM An Example…

3. 3 Architecture Study Framework L2 Destinations Lunar Orbit or L-2 NEOs Phobos Mars Surface Launch Propulsion Options SDLV (Baseline for Comparison) HC-ORSC Core HC-GG Core H2/O2 Core Solid/Liquid Booster Options Liquid Upper Stage Options In-Space Propulsion Options Crew Cargo LOX/H2LOX/H2 LOX/CH4SEP NTR NTR ISRU Launch and In-Space Phases linked by: Total in-space mass and volume requirements Launch Vehicle/in-space hand-off orbit Launch Manifest Commonality opportunities Mission Phases ‹#›

4. 4 DR=Direct Return O=Option Delivered Mass Requirements for Destinations Multi-Destination Mission Elements enables affordable approach ‹#›

5. 5 In-Space Propulsion Options Only included options which are realistic for next 20 years Performance metrics were defined from already demonstrated ground testing Complete Stage Mass models were developed for each technology to use in the Concepts of Operations ElementPropellantSpecific Impulse, s Thrust Cryogenic Propulsion (1 p.432) LOX/LH245267– 222kN (5-50klbf) descent/ascent thrust was not yet evaluated Soft Cryogenic PropulsionLOX/CH4350 Semi-Cryogenic PropulsionLOX/RP1349 Nuclear Thermal Rocket (2 p.25) LH2900 Hall Thruster Systems ( p.11) Xenon or Krypton300040mN/kW or 32mN/kW Gridded Ion Thruster SystemsXenon600025mN/kW [i] [i] Manzella, David, et. al., “Laboratory Model 50 kW Hall Thruster,” NASA TM-2002-211887, September 2002. [ii] [ii] Herman, Dan, “NASA’s Evolutionary Xenon Thruster (NEXT) Project Qualification Propellant Throughput Milestone: Performance, Erosion, and Thruster Service Life Prediction After 450 kg,” NASA TM-2010-216816, May 2010. [iii] [iii] Aerojet, “NASA Completes Altitude Testing of Aerojet Advanced Liquid Oxygen/Liquid Methane Rocket Engine,” May 4, 2010. [iv] [iv] http://www.astronautix.com/engines/rd58.htm, cited: January 17, 2011. For each propulsion option we established several CONOPS options to trade Crew and cargo split, direct return vs. LEO basing, LMO vs. Phobos, how Orion is used, ISRU, etc IMLEO was then calculated for each CONOPs ‹#›

6. 6 Example CONOPS: Crew Segment of NEO Mission (Reusable Space Habitat Version) ‹#›

7. 7 Example CONOPS: Crew Segment of Phobos Mission ‹#›

8. 8 Conclusions from Architecture Comparison High thrust in-space propulsion options include: –Lox-hydrogen for Earth departure –Lox-methane for landers and ascent vehicles –Nuclear thermal rockets for crew transit Each of these shows benefits by itself, but can also be employed in a way in an overall architecture that enhances the standalone merits Supporting technologies like ISRU (and SEP) provide major combinative benefit Aerojet ProprietaryAerojet Official Use Only

9. 9 Final Comment Selection of one technology as a principal thrust can have ripple impacts From the example: – If ISRU were selected as a key long term investment priority, then a focus on lox-methane for deep space cryo stages (not EDS) would be advised –If NTR is selected as a key long term technology, then CFM for long duration storage of hydrogen would be advised and perhaps use of lox-hydrogen for deep space cryo stages is better Aerojet ProprietaryAerojet Official Use Only Thank you for the opportunity to present