page_title: Retrograde and prograde motion
hierarchical_section_title: Retrograde and prograde motion
caption_attribution_description: English: Retrograde orbit
context_page_description: Retrograde motion in astronomy is, in general, orbital or rotational motion of an object in the direction opposite the rotation of its primary, that is, the central object. It may also describe other motions such as precession or nutation of an object's rotational axis. Prograde or direct motion is more normal motion in the same direction as the primary rotates. However, "retrograde" and "prograde" can also refer to an object other than the primary if so described. The direction of rotation is determined by an inertial frame of reference, such as distant fixed stars.
  In our Solar System, the orbits about the Sun of all planets and most other objects, except many comets, are prograde, i.e. in the same direction as the Sun rotates. Except for Venus and Uranus, planetary rotations are also prograde. Most natural satellites have prograde orbits about their planets. Prograde satellites of Uranus orbit in the direction Uranus rotates, which is retrograde to the Sun. Nearly all regular satellites are tidally locked and thus have prograde rotation. Retrograde satellites are generally small and distant from their planets, except Neptune's satellite Triton, which is large and close.
context_section_description: Retrograde motion in astronomy is, in general, orbital or rotational motion of an object in the direction opposite the rotation of its primary, that is, the central object (right figure). It may also describe other motions such as precession or nutation of an object's rotational axis. Prograde or direct motion is more normal motion in the same direction as the primary rotates. However, "retrograde" and "prograde" can also refer to an object other than the primary if so described. The direction of rotation is determined by an inertial frame of reference, such as distant fixed stars.
  In our Solar System, the orbits about the Sun of all planets and most other objects, except many comets, are prograde, i.e. in the same direction as the Sun rotates. Except for Venus and Uranus, planetary rotations are also prograde. Most natural satellites have prograde orbits about their planets. Prograde satellites of Uranus orbit in the direction Uranus rotates, which is retrograde to the Sun. Nearly all regular satellites are tidally locked and thus have prograde rotation. Retrograde satellites are generally small and distant from their planets, except Neptune's satellite Triton, which is large and close. All retrograde satellites are thought to have formed separately before being captured by their planets.
  Most low-inclination artificial satellites of Earth have been placed in a prograde orbit, because in this situation less propellant is required to reach orbit when launching in a prograde direction.
caption: Retrograde orbit: the satellite (red) orbits in the direction opposite to the rotation of its primary (blue/black)