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Dr. Todd A. Ely

Principal Navigation Engineer

About

Bio

Since 1999, Dr. Ely has been at the Jet Propulsion Laboratory developing and implementing navigation systems and architectures for many projects – big and small – including the Mars Network, the Electra radio, JPL’s MONTE navigation software, the Constellation Program, and the Altair lunar lander. In 2011, he became the principal investigator for the DSAC Technology Demonstration Mission that completed operations in September 2021. Dr Ely’s current focus is on lunar and Mars navigation, space based VLBI, and the advancement of atomic clock and autonomous navigation technologies. He is also a former professor and Air Force Officer.

Education

  1. PhD in Aeronautics and Astronautics, Purdue University, 1996
  2. MS in Aeronautics and Astronautics, Purdue University, 1988
  3. BS in Aeronautical and Astronautical Engineering, Purdue University, 1986

Achievements

Awards & Recognitions

  • NASA Award | NASA Outstanding Public Leadership Medal (2020)
  • JPL Award | JPL Magellan Award (2020)
  • JPL Ranger Award (2012)
  • JPL Principal Designation | 392K - Mission Design And Navigation System Engineering (2007)

Publications

Journal Articles

  1. Y. Bar-Sever et al., “Architectures and Technology Investment Priorities for Positioning, Navigation, and Timing at the Moon and Mars,” Interplanetary Network Progress Report, vol. 42, no. 237, pp. 1–60, May 2024.
  2. T. Ely, Z. Towfic, and D. Sorensen, “Formulation and Characterization of One-Way Radiometric Tracking with the Iris Radio Using a Chip-Scale Atomic Clock,” navi, vol. 71, no. 1, p. navi.633, 2024, doi: 10.33012/navi.633.
  3. F. De Marchi et al., “Testing the gravitational redshift with an inner Solar System probe: The VERITAS case,” Phys. Rev. D, vol. 107, no. 6, p. 064032, Mar. 2023, doi: 10.1103/PhysRevD.107.064032.
  4. M. M. Rybak, P. Axelrad, C. LeDesma, D. Z. Anderson, and T. Ely, “Application of shaken lattice interferometry based sensors to space navigation,” Advances in Space Research, p. S0273117722011668, Dec. 2022, doi: 10.1016/j.asr.2022.12.050.
  5. D. P. Lubey and T. A. Ely, “Anomaly Detection in Autonomous Deep-Space Navigation via Filter Bank Gating Networks,” Applied Sciences, vol. 12, no. 21, p. 11161, Nov. 2022, doi: 10.3390/app122111161.
  6. J. Seubert, T. A. Ely, and J. Stuart, “Results of the Deep Space Atomic Clock Deep Space Navigation Analog Experiment,” Journal of Spacecraft and Rockets, pp. 1–12, Jul. 2022, doi: 10.2514/1.A35334.
  7. T. A. Ely, S. Bhaskaran, N. Bradley, · T Joseph, W. Lazio, and T. Martin-Mur, “Comparison of Deep Space Navigation Using Optical Imaging, Pulsar Time-of-Arrival Tracking, and/or Radiometric Tracking,” The Journal of the Astronautical Sciences, vol. 69, no. 2, pp. 385–472, Apr. 2022, doi: 10.1007/S40295-021-00290-Z.
  8. M. M. Rybak, P. Axelrad, J. Seubert, and T. Ely, “Chip Scale Atomic Clock–Driven One-Way Radiometric Tracking for Low-Earth-Orbit CubeSat Navigation,” Journal of Spacecraft and Rockets, vol. 58, no. 1, pp. 200–209, Oct. 2021, doi: 10.2514/1.A34684.
  9. T. A. Ely, J. Seubert, N. Bradley, T. Drain, and S. Bhaskaran, “Radiometric Autonomous Navigation Fused with Optical for Deep Space Exploration,” The Journal of the Astronautical Sciences, vol. 68, no. 1, pp. 300–325, 2021, doi: 10.1007/s40295-020-00244-x.
  10. E. A. Burt et al., “Demonstration of a trapped-ion atomic clock in space,” Nature, vol. 595, no. 7865, pp. 43–47, 2021, doi: 10.1038/s41586-021-03571-7.
  11. C. Zhai et al., “Accurate Ground-based Near-Earth-Asteroid Astrometry Using Synthetic Tracking,” The Astronomical Journal, vol. 156, no. 2, p. 65, Jul. 2018, doi: 10.3847/1538-3881/aacb28.
  12. T. A. Ely, E. A. Burt, J. D. Prestage, J. M. Seubert, and R. L. Tjoelker, “Using the Deep Space Atomic Clock for Navigation and Science,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 65, no. 6, pp. 950–961, Jun. 2018, doi: 10.1109/TUFFC.2018.2808269.
  13. R. L. Tjoelker et al., “Mercury Ion Clock for a NASA Technology Demonstration Mission,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 63, no. 7, 2016, doi: 10.1109/TUFFC.2016.2543738.
  14. T. A. Ely, “Transforming Mean and Osculating Elements Using Numerical Methods,” The Journal of the Astronautical Sciences, vol. 62, no. 1, pp. 21–43, Jun. 2015, doi: 10.1007/s40295-015-0036-2.
  15. T. A. Ely, “Mean Element Propagations Using Numerical Averaging,” The Journal of the Astronautical Sciences, vol. 61, no. 3, pp. 275–304, Dec. 2014, doi: 10.1007/s40295-014-0020-2.
  16. T. A. Ely, M. Heyne, and J. E. Riedel, “Altair Navigation During Translunar Cruise, Lunar Orbit, Descent, and Landing,” Journal of Spacecraft and Rockets, vol. 49, no. 2, pp. 295–317, Mar. 2012, doi: 10.2514/1.52233.
  17. E. G. Lightsey, A. E. Mogensen, P. D. Burkhart, T. A. Ely, and C. Duncan, “Real-Time Navigation for Mars Missions using the Mars Network,” AIAA Journal of Spacecraft and Rockets, vol. 45, no. 3, pp. 519–533, 2008, doi: http://dx.doi.org/10.2514/1.30974.
  18. T. A. Ely and E. Lieb, “Constellations of elliptical inclined lunar orbits providing polar and global coverage,” Journal of the Astronautical Sciences, vol. 54, no. 1, pp. 53–67, 2006.
  19. R. X. Li et al., “Initial results of rover localization and topographic mapping for the 2003 mars exploration rover mission,” Photogrammetric Engineering and Remote Sensing, vol. 71, no. 10, pp. 1129–1142, 2005.
  20. T. A. Ely, “Stable constellations of frozen elliptical inclined lunar orbits,” Journal of the Astronautical Sciences, vol. 53, no. 3, pp. 301–316, 2005.
  21. R. C. Hastrup et al., “Mars network for enabling low-cost missions,” Acta Astronautica, vol. 52, no. 2–6, pp. 227–235, 2003, doi: Pii S0094-5765(02)00161-3.
  22. T. A. Ely, “Eccentricity impact on east-west stationkeeping for global positioning system class orbits,” Journal of Guidance Control and Dynamics, vol. 25, no. 2, pp. 352–357, 2002.
  23. T. P. Crain, R. H. Bishop, and T. A. Ely, “Event detection and characterization during autonomous interplanetary navigation,” Journal of Guidance Control and Dynamics, vol. 25, no. 2, pp. 394–403, 2002.
  24. C. D. Edwards et al., “Strategies for telecommunications and navigation in support of Mars exploration,” Acta Astronautica, vol. 48, no. 5–12, pp. 661–668, 2001.
  25. T. A. Ely and K. C. Howell, “East-west stationkeeping of satellite orbits with resonant tesseral harmonics,” Acta Astronautica, vol. 46, no. 1, pp. 1–15, 2000.
  26. T. A. Ely, R. H. Bishop, and T. Crain, “Adaptive interplanetary navigation using genetic algorithms,” Journal of the Astronautical Sciences, vol. 48, no. 2–3, pp. 287–303, 2000.
  27. T. A. Ely, W. Crossley, and E. A. Williams, “Satellite constellation design for zonal coverage using genetic algorithms,” Journal of the Astronautical Sciences, vol. 47, no. 3–4, pp. 207–228, 1999.
  28. T. A. Ely and K. C. Howell, “Dynamics of artificial satellite orbits with tesseral resonances including the effects of luni- solar perturbations,” Dynamics and Stability of Systems, vol. 12, no. 4, pp. 243–269, 1997.
  29. T. A. Ely and K. C. Howell, “Long-term evolution of artificial satellite orbits due to resonant tesseral harmonics,” Journal of the Astronautical Sciences, vol. 44, no. 2, pp. 167–190, 1996.