issajousLunarSunHeliocentricEarth's orbitMars cyclerHeliosynchronousOtherLunar cyclerParametersShapeSizee  Eccentricitya  Semi-major axisb  Semi-minor axisQ, q  ApsidesOrientationi  InclinationΩ  Longitude of the ascending nodeω  Argument of periapsisϖ  Longitude of the periapsisPositionM  Mean anomalyν, θ, f  True anomalyE  Eccentric anomalyL  Mean longitudel  True longitudeVariationT  Orbital periodn  Mean motionv  Orbital speedt0  EpochManeuversBi-elliptic transferCollision avoidance (spacecraft)Delta-vDelta-v budgetGravity assistGravity turnHohmann transferInclination changeLow-energy transferOberth effectPhasingRocket equationRendezvousTransposition, docking, and extractionOrbitalmechanicsAstronomical coordinate systemsCharacteristic energyEscape velocityEphemerisEquatorial coordinate systemGround trackHill sphereInterplanetary Transport NetworkKepler's laws of planetary motionLagrangian pointn-body problemOrbit equationOrb