Status of the Laser Risk Reduction Program at LaRC Michael Kavaya, Upendra Singh NASA/LaRC Working Group on Space-Based Lidar Winds Sedona, AZ Feb. 1-3, 2005

X-Centric LRRP was R&D-centric and knowledge-centric LRRP was jointly funded by Earth Science Enterprise and Aerospace Technology Enterprise: ~50/50 Jan. 14, 2004 – NASA began Exploration Initiative NASA HQ Reorganization ATE part of LRRP given to Exploration Systems Mission Directorate ESMD held ICP competition: ESTO/LaRC/GSFC proposal accepted – LLTE; funding is 50% x (15%, 42.5%, 42.5%) FY05 – big drop in total funding Now LRRP is Exploration-centric LRRP never has been earth science mission-centric

LRRP LaRC Funding $MFY02FY03FY04FY05FY06FY07Totals ESMD (T), formerly OATE(R) Gross* Procurement CS FTE PBC WYE ** Science/ESTO, formerly OESE(Y)/ESTO Gross* Procurement CS FTE PBC WYE TotalGross* Procurement CS FTE PBC WYE ~ ~ *** Begin NASA’s Exploration Initiative Begin Full Cost Accounting * Different definitions under BAU & FCA ** Was 2.6 until 11/30/04 *** Includes ~ 4 surfeit FTEs Begin Laser/Lidar 4 Exploration Begin Laser Risk Reduction Program

2-Micron Pulsed Transmitter Laser Development Pump Laser Diode Arrays Development, Characterization, & Qualification (792 nm) Wavelength Conversion From 1-Micron to UV, High E Detector/Receiver Advancement For Direct and Coherent Detection at 2-Microns Laser Physics, New Materials LaRC Components Of LRRP, FY02-04

LaRC LRRP Accomplishments Discovered more efficient 2-micron laser material - mitigates large resource req’t of s/c Demonstrated over 1 Joule pulse energy at 2 microns; (world record by order of magnitude) - enables active wind & CO 2 measurement Designed fully conductively cooled 2 micron laser head - mitigates thermal mgmt risk of high-power lasers Developed diode laser characterization and lifetime facilities - to understand failure modes of future solid state lasers Developed innovative UV generation architectures - enablers for trop ozone Developed 2-micron detector characterization facility - to enable better detector fabrication Developed high responsivity detector Built first integrated receiver breadboard for 2-micron coherent lidar - more compact & robust V b1 V b2 GND V cc1 V cc2 Out 1 Out 2 75  m InGaAs Detectors Transimpedance Amplifiers Al 2 O 3 Substrate Capacitor

LaRC Components Of LRRP, FY05-07 Task 1. 2-Micron Pulsed Laser Transmitter 2-Micron Testbed Compact 2-Micron Laser (1a) 12/04 Develop requirements for an engineering hardened 2-micron laser 3/05 Develop conceptual engineering design for a hardened 2-micron laser test bed 8/05 Complete mechanical design 9/05 Critical design review Amplifier Development (1b) 10/04 Complete laser diode coupling efficiency analysis 1/05 Complete thermal and stress analysis 4/05 Complete amplifier head design 8/05 Complete amplifier module design Phase Conjugate Mirror (1c) 12/04 Develop criteria for selecting potential PCM approaches compatible with 2-micron lasers 5/05 Develop and improve amplifier models to optimize the amplifier performance with PCM technology

LaRC Components Of LRRP, FY05-07 Task 1. 2-Micron Pulsed Laser Transmitter (cont.) Tm Fiber Pumped Ho Laser (1d) 3/05 Develop a model to simulate an end-pumped Ho laser 3/05 Characterize the commercial Tm fiber laser 6/05 Complete a design for a CW Ho laser directly pumped by Tm fiber laser 9/05 Complete a continuous wave Ho laser directly pumped by Tm fiber laser Radiation & Contamination Mitigation (1e) 4/05 Define the radiation hardness levels and generate parts list of potential space-bound components 9/05 Develop and design contamination testing station Task 2. Mars Orbiter Lidar Modeling & Requirements (2a) 7/05 Lidar performance model of Mars wind measurement 7/05 Rapidly switched seed source 8/05 Lidar performance model of Mars CO 2 measurement 9/05 Design of orbiting lidar system 9/05 Double-pulsed wavelength-switched injection seeding validation

LaRC Components Of LRRP, FY05-07 Task nm Laser Diode Arrays Characterization and Qualification (3a) 6/05 Develop a setup for measuring package-induced stresses 9/05 Evaluate different LDAs from different suppliers Technology Advancement Addressing Reliability Issues (3b) 1/05 Design and fabricate LDAs with improved geometry 6/05 Fabricate experimental LDAs using advanced composite submount materials Task 4. Detector Development For 2-Micron Direct DIAL 3/05 Develop phototransistors suitable for 2 micron with sensitivity > 1000 A/W at 2 microns, 200 micron diameter collecting area, NEP < 2E-14 W/Hz**0.5, and QE of 80% 4/05 Validate detector performance in subsystem 7/05 Design and build a mask with standard collecting area diameter of 1000 microns

LaRC Components Of LRRP, FY05-07 Task 5. UV Wavelength Conversion Technologies from 1 Micron 6/05 Complete RISTRA OPO and SFG based nonlinear optics setup generating 320 nm wavelength 9/05 Complete the integration of the Nd:YAG pump laser and nonlinear optics setup generating 308 nm wavelength Task 6. Advanced Receiver For 2-Micron Coherent Doppler Lidar 3/05 Design optimized wideband receiver boards (0.5, 1.0, 5.0 GHz) 9/05 Fabricate and test 500 MHz receiver board

Conclusions LRRP is a great idea, but by no means the only thing that needs doing LRRP has survived so far the upheavals at NASA The new form of LRRP will continue to advance technology helpful to the global winds measurement NASA does not appoint a measurement “shepherd” with a budget to oversee theory, modeling, technology devel., technology and technique validation, and space readiness validation related to that one measurement. I wonder if that approach would succeed? Will Mars be a stepping stone to earth?