NASA Space Technology Research Fellow
The University of Texas at Austin
September 2012 – Present
- Developed novel method to compute statistical estimation filter process noise that requires no tuning, enhances navigation performance (lowering errors and improving formal state uncertainty representation), accounts for time and state-dependent dynamical model errors, and can be pre-computed for use in onboard spacecraft computers with limited computational capabilities
- Showed that modern higher order statistical estimation techniques better capture non-linear dynamics and measurement models in challenging mission scenarios about small bodies
- Built Simultaneous Localization and Mapping (SLAM) capability to simultaneously estimate spacecraft state and spin state of a small body, as well as landmarks on small body surface; used this capability to estimate the small body rotational dynamics for range of scenarios, including comet 67P visited by the European Space Agency (ESA) Rosetta mission
- Processed ESA simulated images of a tumbling small body, to evaluate the spin state estimation algorithms previously developed, in partnership with NASA JPL
- Collaborated with researchers at NASA’s Goddard Space Flight Center, Jet Propulsion Laboratory, and Ames Research Center during “visiting technologist experiences” provided by NSTRF
September 2009 – October 2012 (3 years 2 months)
- Primary architect of Maneuver Decision Process for MMS Ground System
- Performed GPS navigation analysis for NASA’s Magnetospheric MultiScale (MMS) mission, including Monte Carlo analysis for Flight Dynamics Subsystem Critical Design Review (CDR) and Mission CDR to ensure all mission navigation requirements were met
- Investigated sensitivity of MMS GPS navigation performance to major error sources, including clock errors and acceleration knowledge error, and wrote conference paper detailing this analysis
- Determined sources of systematic bias seen in navigation Monte Carlo results
- Performed statistical post-processing of navigation results and GPS measurement data
- Wrote 14 official reports for the MMS task detailing various MMS navigation analyses conducted
- Tested and assisted in developing Goddard Enhanced Onboard Navigation System (GEONS) and new GPS measurement simulation software DataGen used for MMS navigation analysis, including fully assessing beta versions of GEONS and DataGen before official release
- Coordinated with GEONS development team to ensure that all enhancements to GEONS needed for navigation analysis were completed in time to meet analysis deadlines
- Collaborated with development team of experimental Navigator MMS GPS Receiver to ensure GPS navigation models used by navigation analysis team aligned with latest Navigator test results
- Created acceleration knowledge error model used for navigation Monte Carlo analysis
- Developed project plans for navigation analysis, integrated with Mission Design team deadlines
- Enhanced Mission Design method of constructing truth trajectories needed for navigation analysis
- Trained new Navigation team members on how to use navigation software such as GEONS
- Participated in Deep Space Working Group and Controls Working Group activities
Graduate Research Assistant
University of Texas at Austin Center for Space Research
August 2007 – May 2009 (1 year 10 months)
- Used Mathematica and Piranha (Italian-built celestial-mechanics-oriented symbolic manipulator) to develop analytic expressions for particular satellite orbit properties
- Worked on projects related to Ice, Cloud and land Elevation Satellite (ICESat)
Outer Planets Navigation Group Intern
Jet Propulsion Laboratory
June 2008 – August 2008 (3 months)
- Created autonomous navigation filter using optical measurements for simulated spacecraft orbiting, hovering, and landing on small bodies (asteroids and comets)
- Employed landmark-based optical measurement system with layered filtering
- Generated and utilized center of brightness based optical measurements
- Implemented “Sliding Window” technique for long duration Batch Filter processing
- Integrated spacecraft maneuver compatibility into navigation simulation
- Built landing scenario with minimum energy Lambert Targeting for analysis of landing navigational accuracy
- Utilized Monte Carlo methods for various simulation profiles
Mission Design and Navigation Group Intern
NASA Goddard Space Flight Center
June 2007 – August 2007 (3 months)
- Performed navigation analysis for potential Terrestrial Planet Finder – Occulter mission using GPS Enhanced Onboard Navigation System (GEONS) software
- Generated spacecraft trajectories using General Mission Analysis Toolkit (GMAT) and STK
- Developed documentation for future users of GEONS and GMAT
International Space Station Instructor
Training Division at NASA Johnson Space Center (JSC)
United Space Alliance
January 2005 – August 2006 (1 year 8 months)
Motion Control Group (MCG) Co-op
- Built and taught International Space Station (ISS) Global Positioning System (GPS) class
- Taught Motion Control System (MCS) Birds Eye View (BEV) class
- Completed MCS Specialist Mastery assessment – test of all ISS GN&C systems
- Completed initial six month instructor certification block in three months
Daily Operations Group and Command & Data Handling (CDH) Group Co-op
- Taught two classes: Operations Local Area Network (LAN) Malfunctions, Operations LAN Data Storage and Management
- Taught 2004 astronaut class, future ISS crewmembers, others
- Rated one of top four instructors in Training Division by 2004 astronaut class
Trulson’s Tae Kwon Do
July 2000 – August 2003 (3 years 2 months)
- Taught students from ages 5 to adult
- Assistant Instructor for 3 years before promoted to Head Instructor
- 3rd Degree Black Belt in Tae Kwon Do
Honors and Awards
- 2012 NASA Space Technology Research Fellowship
- 2012 UT Austin Cockrell School of Engineering / University Recruitment Fellowship – forced to decline
- 2012 UT Austin Thrust 2000 Graduate Fellowship in Engineering
- 2012 UT Austin Graduate Dean’s Prestigious Fellowship
- 2007 CEIA National Co-operative Education Student of the Year – representing University of Texas at Austin Cockrell School of Engineering
- Johnson Space Center Training Division, Motion Control Group Silver Gyro Award
- 2nd Place Graduate Team in NASA’s 2008 National RASC-AL Mission Design Competition
Presentations and Speaking Engagements
- “Spin State Estimation of Tumbling Small Bodies,” AAS/AIAA Spaceflight Mechanics Meeting, January 2015, AAS 15-363.
- “Small Body Autonomous Optical Navigation and Spin State Estimation,” poster and presentation, November, 2014.
- “Small Body Optical Navigation Using The Additive Divided Difference Sigma Point Filter,” AAS/AIAA Spaceflight Mechanics Meeting, January 2014, AAS 14-422.
- “Expected Navigation Flight Performance for the Magnetospheric Multiscale (MMS) Mission,” AAS/AIAA Spaceflight Mechanics Meeting, January 2012. Paper AAS 12-199.
- “Magnetospheric Multiscale (MMS) Mission Navigation Concept,” AIAA Region I Young Professional, Student, and Education Conference, November 2011.
- “Sensitivity of Magnetospheric Multi-Scale (MMS) Mission Navigation Accuracy to Major Error Sources,” AAS/AIAA Spaceflight Mechanics Meeting, February 2011. Paper AAS 11-207.
- “Mission Orbit Navigation Analysis Approach & Modeling Assumptions,” MMS Flight Dynamics Subsystem Critical Design Review (CDR), June 2010.
- “Psychology of Decision Making for Engineers,” a.i. solutions analyst meeting, September 2010.
- “Terrestrial Planet Finder – Occulter: Navigation,” poster and presentation, NASA Goddard Summer Internship Program, August 2007.
- Two-time Panelist, “Why Co-op?” event, panel discussion about UT Co-op Program, 2008 and 2009.