John Christian
Georgia Institute of Technology
Seminar Information
Optical navigation (OpNav) is one of the principal forms of navigation for interplanetary spacecraft. This talk explores the origin and history of OpNav---from before the space age to the present---and motivates the new problems facing spacecraft navigators today. Against this backdrop, a number of recent OpNav experimental results are presented, with a focus on the 2023 Lunar Flashlight OpNav experiment called LONEStar. Operated by Georgia Tech, the Lunar Flashlight mission was launched in December 2022 and ejected from the Earth-Moon system by a May 2023 flyby of Earth. After leaving the Earth-Moon system, and while in heliocentric space, the Georgia Tech team commanded the Lunar Flashlight spacecraft to collect images of the Earth, Moon, Mercury, Mars, Jupiter, and Saturn. These images were used for a number of novel navigation experiments, including the first-ever demonstration of interplanetary navigation using only optical sightings of distant planets. Results from these experiments will be presented.
Dr. Christian is a professor at the Georgia Institute of Technology, where he is also the AE School's Associate Chair for Graduate Programs. He is director of the Space Exploration Analysis Laboratory (SEAL) and is an expert in astrodynamics, image-based spacecraft navigation, and estimation theory. Prior to joining the faculty at Georgia Tech, Dr. Christian held faculty appointments at West Virginia University and Rensselaer Polytechnic Institute. Prior to his positions in academia, he was an aerospace engineer at the NASA Johnson Space Center in the GNC Autonomous Flight Systems Branch. Dr. Christian develops algorithms for extracting information from space sensor data. He is most well-known for his contributions in the use of space imagery for celestial optical navigation (OpNav), planetary terrain relative navigation (TRN), and star/asterism identification. He has supported navigation activities for the Space Shuttle, International Space Station (ISS), Orion/Artemis, Lunar Flashlight, and other space exploration missions. His algorithms have been incorporated into numerous other space exploration missions. He is author of the graduate-level textbook "Fundamentals of Spacecraft Optical Navigation." Dr. Christian is an AAS Fellow and an AIAA Associate Fellow. He is an associate editor of the AAS Journal of the Astronautical Sciences. He holds a Ph.D. in aerospace engineering from the University of Texas at Austin.