Lunar Resonance Orbits

NASA’s Interstellar Boundary Explorer (IBEX) mission was recently maneuvered into a unique long–term stable Earth orbit. By synchronizing the satellite’s orbital period to integer fractions of the Moon’s sidereal period, PM = 27.3 days (e.g., PM/2=13.6 days, PM/3= 9.1 days), and phasing apogee to stay away from the Moon, very long–term stability can be achieved. While probably not permanently stable, these IBEX–like orbits represent a new class of Earth orbits that are effectively stable for decades, lasting far longer than typical satellite lifetimes. These orbits provide cost–effective and nearly ideal locations for long–term space weather observations from spacecraft that can remotely image the Earth’s magnetosphere from the outside while simultaneously providing external (solar wind or magnetosheath) observation over most of their orbits. Utilized with multiple–spacecraft, such orbits would allow continuous and simultaneous monitoring of the magnetosphere in order to help predict and mitigate adverse space weather–driven effects.

References:

McComas, D.J., J.P. Carrico, B. Hautamaki, M. Intelisano, R. Lebois, M. Loucks, L. Policastri, M. Reno, J. Scherrer, N.A. Schwadron, M. Tapley, and R. Tyler, A new class of long–term stable lunar resonance orbits: Space weather applications and the Interstellar Boundary Explorer, Space Weather, 9, S11002, doi: 10.1029/2011SW000704, 2011.