After more than fifty years since the Apollo program, we are encountering a revived, second Space Race. However, this time, international space agencies are not only seeking to return humans to the Moon, but to further establish a sustainable human presence. For this goal, NASA and the ESA have conceptualized the initial framework for a GPS-like constellation for the Moon to provide continuous navigation and communication services for future lunar missions. To ensure reliable services, these future lunar systems will require precise time synchronization. However, given the stringent Size, Weight, and Power (SWaP) requirements for the lunar environment, we investigate the design of a SmallSat-based constellation with an inexpensive, low-SWaP onboard clock, which harnesses terrestrial GPS signals to maintain continuous, precise timing on the lunar satellites. We demonstrate that with low-SWaP clocks, the lunar constellation can provide low ranging of < 10 meter errors to enable future lunar exploration missions. 

Related Publications:

• M. Cortinovis, T. Mina, and G. Gao, “Assessment of single satellite-based lunar positioning for the NASA Endurance mission,” in IEEE Aerospace Conference, Big Sky, MT, Mar. 2024, accepted.

• S. Bhamidipati, T. Mina, A. Sanchez, and G. Gao, “Satellite constellation design for a lunar navigation and communication system,” NAVIGATION, Journal of the Institute of Navigation, vol. 70, no. 4, 2023. [paper] [video]

• S. Bhamidipati, T. Mina, and G. Gao, “A case study analysis for designing a lunar navigation satellite system with time-transfer from Earth-GPS,” NAVIGATION, Journal of the Institute of Navigation, vol. 70, no. 4, 2023. [paper] [video]

• S. Bhamidipati, T. Mina, and G. Gao, “Time transfer from GPS for designing a SmallSat-based lunar navigation satellite system,” NAVIGATION: Journal of the Institute of Navigation, vol. 69, no. 3, 2022. [paper] [video]

• S. Bhamidipati, T. Mina, and G. Gao, “Lunar navigation: A case study analysis,” Inside GNSS, vol. 17, no. 6, pp. 40–47, Nov.–Dec. 2022. Cover Story. [article]

• S. Bhamidipati, T. Mina, A. Sanchez, and G. Gao, “A lunar navigation and communication satellite system with Earth-GPS time transfer: Design and performance considerations,” in Institute of Navigation (ION) GNSS+ Conference, Institute of Navigation, Denver, CO, Sep. 2022, pp. 537–553. Best Presentation of the Session Award. [paper] [slides] [video]

• S. Bhamidipati, K. Iiyama*, T. Mina*, and G. Gao, “Time-transfer from terrestrial GPS for distributed lunar surface communication networks,” in IEEE Aerospace Conference, Big Sky, MT, Mar. 2022, pp. 1-15. [paper] [slides]

• S. Bhamidipati, T. Mina, and G. Gao, “A case study analysis for designing a lunar navigation satellite system with time-transfer from Earth-GPS,” in Institute of Navigation (ION) International Technical Meeting (ITM) Conference, Long Beach, CA, Jan. 2022, pp. 407–419. [paper] [slides] [video]

• S. Bhamidipati, T. Mina, and G. Gao, “Design considerations of a lunar navigation satellite system with time-transfer from Earth-GPS,” in Institute of Navigation (ION) GNSS+ Conference, St. Louis, MO, Sep. 2021, pp. 950–965. Best Presentation of the Session Award. [paper] [slides] [video]