Technology Input Formats and Background Appendix B

Technology Readiness Levels (Mankins, 1995) Technology Readiness Levels Summary TRL 1 Basic principles observed and reported TRL 2 Technology concept and/or application formulated TRL 3 Analytical and experimental critical function and/or characteristic proof- of-concept TRL 4 Component and/or breadboard validation in laboratory environment TRL 5 Component and/or breadboard validation in relevant environment TRL 6 System/subsystem model or prototype demonstration in a relevant environment (ground or space) TRL 7 System prototype demonstration in a space environment TRL 8 Actual system completed and “flight qualified” through test and demonstration (ground or space) TRL 9 Actual system “flight proven” through successful mission operations

Research & Development Degree of Difficulty (R&D 3 ) (Mankins, 1998) “A measure of how much difficulty is expected to be encountered in the maturation of a particular technology is needed to complement the existing Technology Readiness Levels (TRLs) metric.” R&D 3 Summary R&D 3 – I A very low degree of difficulty is anticipated in achieving research and development objectives for this technology. Probability of Success in “Normal” R&D Effort 99% R&D 3 – II A moderate degree of difficulty should be anticipated in achieving R&D objectives for this technology. Probability of Success in “Normal” R&D Effort 90% R&D 3 – III A high degree of difficulty anticipated in achieving R&D objectives for this technology. Probability of Success in “Normal” R&D Effort 80% R&D 3 – IV A very high degree of difficulty anticipated in achieving R&D objectives for this technology. Probability of Success in “Normal” R&D Effort 50% R&D 3 – V The degree of difficulty anticipated in achieving R&D objectives for this technology is so high that a fundamental breakthrough is required. Probability of Success in “Normal” R&D Effort 20%

Description Laser interferometric ranging system for vector range determination on multiple spacecraft. HeNe laser on host spacecraft and retroreflector on daughter spacecraft. Benefits Optimized for closed loop operation fully radiation-tolerant design for continuous operation can function with or without estimator on low power embedded processor 12 kg on host, 0.1 kg on daughter Performance, Power, and Mass: 10 nm, 10 Hz data rate 10 W avg power, 25 W peak 5 yr expected lifetime Projected Cost and time to TRL 10 nm: $12.5M, 4 yrs Projected Cost and time to TRL 3 nm: $32M, 9 yrs Challenges laser phase stability stray light problems from sun ensuring reliability beyond 6 months TRL: 2 (concept formulated) Analytical critical function demonstrated (refs.), but experimental function and/or characteristic proof-of-concept not demonstrated (ref. 2). References 1.Smith J., “A Formation Flying Laser Ranging System,” AIAA Paper XXXX-XXXX. 2.Jones, T., “A laboratory demonstration of precision formation flying,” AIAA GN&C Conf, Aug R&D 3 : IV (very high) Requires dramatic extrapolation of existing capability to reduce the reduce the phase stability by an order of magnitude Fine laser ranging system Relative navigation and metrology sensors, algorithms, and systems Example Hardware

Description Algorithm for precise formation control near Earth-Sun L2 point. Range of validity depends upon performance required. Benefits Accounts for fully nonlinear dynamics Robust to variations and uncertainties in the dynamics Adapts to non-catastrophic failures Demonstrated in laboratory environment with ranging system in the loop to 0.1 mm 3  performance with uncertain dynamics and 1  m precision measurements Projected Cost and time to TRL 6 for 6 spacecraft system: $1.5M, 1.5 yrs Challenges for high precision applications, verification at very fine levels can push to limits in machine hardware guaranteeing convergence for significant uncertainties TRL: 4 (component lab validation) Validated closed loop (ref. 1), for 2 spacecraft system. Has not achieved full system demonstration with real spacecraft processor or significant processing limitations. Current thruster technology limitations have not been incorporated at high fidelity. References 1.Smith J., “A Formation Flying Control Algorithm,” AIAA Paper XXXX-XXXX. 2.Jones, T., “A laboratory demonstration of precision formation flying,” AIAA GN&C Conf, Aug R&D 3 : II (moderate) Complexity of implementation grows with number of spacecraft. Precision requirements may dictate significant computational power. Robust, nonlinear formation control algorithm near Earth-Sun L2 point Formation Control actuators, algorithms, and systems Example Algorithm